Sharmin has agreed to help out on the RASC Toronto Centre web site as content editor. Woo hoo. We spent some time today with our computers reviewing processes. It's going to be great having her on the team.
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It was disappointing to see Safari on her MacBook generate 406 Not Acceptable errors. Not good, at all...
Sunday, February 27, 2011
heavy
I heard that the Canadarm, if it were on Earth, would not be able to lift its own weight. Not an issue in microgravity.
Wait a sec'! How did they test it?!
Amazing. Amazing contribution.
Wait a sec'! How did they test it?!
Amazing. Amazing contribution.
Saturday, February 26, 2011
synchronicity
Weird. As the crews of the space shuttle and the space station waited for the large relative motions from docking to dampen out, my clothes washing machine started oscillating...
home in time for docking
Caught the approach and soft dock of the shuttle to station. As Discovery readied for the back-flip, shadows from the solar arrays fell over the fuselage.
And then the snout, as the west coast of South America slid past.
After the RPM, the shuttle sped up to position itself for approach. Coasting around behind the JAXA external experiments rack.
Docked! Look at that. The Dextre robot, Canadarm2, JAXA lab, JAXA H-II (gold), and the NASA space truck. Canadian, Japanese, and American partners all together.
Gear not shown: Russian Soyuz and Progress craft and European ATV.
And then the snout, as the west coast of South America slid past.
After the RPM, the shuttle sped up to position itself for approach. Coasting around behind the JAXA external experiments rack.
Docked! Look at that. The Dextre robot, Canadarm2, JAXA lab, JAXA H-II (gold), and the NASA space truck. Canadian, Japanese, and American partners all together.
Gear not shown: Russian Soyuz and Progress craft and European ATV.
beautiful Earth
We've only got one...
Somewhere around the NH rendezvous rocket firing, I caught the Discovery shuttle hovering over our little blue world.
Somewhere around the NH rendezvous rocket firing, I caught the Discovery shuttle hovering over our little blue world.
Friday, February 25, 2011
not supported
Oh. That explains a few things.
I learned today, after reading a post by Matthew Gates, that the Stellarium app for the iPhone is not a product released by main Stellarium crew. It is a port by a third party. As such the main Stellarium team does not support it.
This explains why the product is so limited, that there's been little progress on it. It is essentially a different application.
I learned today, after reading a post by Matthew Gates, that the Stellarium app for the iPhone is not a product released by main Stellarium crew. It is a port by a third party. As such the main Stellarium team does not support it.
This explains why the product is so limited, that there's been little progress on it. It is essentially a different application.
Thursday, February 24, 2011
good read
I decided to test the MallinCam "green" cable, recently received.
Borrowed Denis's mini TV with its 12v CLA power cord and composite video cable. Also snagged one of his female-to-female RCA adapters. Grabbed my custom 120VAC-12VDC power supply. MallinCam Hyper Color, its BNC-RCA video cable, and power supply.
Hooked the camera to the monitor to verify signal. After setting the monitor to VIDEO 1 input and applying power to the camera, my mistyped title, from the summer, appeared on the screen.
There was a serial cable already attached to the back of John Smallberries. It terminated in a 25-pin male DB connector. I looked around for a female 25-to-male 9 to attach to the green cable. Unable to tag a simple adapter, I grabbed my old Laplink cable. Knowing it was wired for DTE termination, I located a null modem adapter. Plugged the crazy chain of cables and adapters together and launched the MallinCam Control program by Stephan. Tried a few things but nothing seemed to be working. Removed the null modem. No joy.
Crawled under the desk and discovered another link in the cable madness. Oh boy. This was very messy. Who knows what was connected to what. It was at this point that I realised the RS-485 adapter was but 9 pin. What gender I wondered. Ah ha! Female. It should bolt directly to the computer.
Tossed aside all the other cables and adapters. Hit the Read From button...
Yellow indicator. Joy!
Entered some text (in lower case no less) and pushed it into the camera. Red indicator. w00t! This is gonna make life so much easier...
Next step will be to test it with a serial-USB adapter.
Borrowed Denis's mini TV with its 12v CLA power cord and composite video cable. Also snagged one of his female-to-female RCA adapters. Grabbed my custom 120VAC-12VDC power supply. MallinCam Hyper Color, its BNC-RCA video cable, and power supply.
Hooked the camera to the monitor to verify signal. After setting the monitor to VIDEO 1 input and applying power to the camera, my mistyped title, from the summer, appeared on the screen.
There was a serial cable already attached to the back of John Smallberries. It terminated in a 25-pin male DB connector. I looked around for a female 25-to-male 9 to attach to the green cable. Unable to tag a simple adapter, I grabbed my old Laplink cable. Knowing it was wired for DTE termination, I located a null modem adapter. Plugged the crazy chain of cables and adapters together and launched the MallinCam Control program by Stephan. Tried a few things but nothing seemed to be working. Removed the null modem. No joy.
Crawled under the desk and discovered another link in the cable madness. Oh boy. This was very messy. Who knows what was connected to what. It was at this point that I realised the RS-485 adapter was but 9 pin. What gender I wondered. Ah ha! Female. It should bolt directly to the computer.
Tossed aside all the other cables and adapters. Hit the Read From button...
Yellow indicator. Joy!
Entered some text (in lower case no less) and pushed it into the camera. Red indicator. w00t! This is gonna make life so much easier...
Next step will be to test it with a serial-USB adapter.
presentation notes up
Put my presentation notes online in the RASC Toronto Centre web site. Along with the month-at-a-glance calendar as a PDF file for download.
http://toronto.rasc.ca/content/tstm1102a.shtml
http://toronto.rasc.ca/content/tstm1102a.shtml
caught the launch
My class finished early. I jumped into the Spaceflight Now web site.
Godspeed Discovery!
Godspeed Discovery!
more applicants
I was expecting one or two but ending up accepting another 4 applicants into my Stellarium course. Sweet. Consequently, these people have filled the first session to the maximum limit of 12 I had set. I'm pleased at the show of interest.
Wednesday, February 23, 2011
delivered TSTM Feb 11
Delivered my The Sky This Month presentation to the RASC Toronto Centre at the Ontario Science Centre. Went fairly well although the "presenter console" in Open Office did not work! Grrr. Got lots of thumbs up. Had 80 handouts--more than enough.
Leslie spotted some typos in the calendar. I wasn't surprised. Working on it at 5:00 AM before coffee was asking for trouble.
Leslie spotted some typos in the calendar. I wasn't surprised. Working on it at 5:00 AM before coffee was asking for trouble.
occultation suggestion
Guy asked me if I wanted to record the Ludmilla occultation coming up on midnight of Mar 7-8. He said that he and Tom are trying for it: Guy's going to observe from The Forks; Tom is going to observe from home (I believe the Cobourg area). He suggested I observe from Long Sault. But I'd need to find a way to get there...
Tuesday, February 22, 2011
meeting handout for Ralph
As Charles was out of town, I asked Ralph if he wanted me to assemble (and photocopy) the meeting presentation handout. He sent over the final version of the PowerPoint file and I grabbed all the copy.
Once again I noticed an issue with the slide layouts. Most of the title and text slides were not formally designated as such. I had to switch them first before the text would export. After that it went fairly smoothly. Stupid Microsoft.
Once again I noticed an issue with the slide layouts. Most of the title and text slides were not formally designated as such. I had to switch them first before the text would export. After that it went fairly smoothly. Stupid Microsoft.
no data on Lem (Toronto)
Tried to record the occultation of asteroid Lem. But I ran into some equipment trouble.
Got everything connected and working but there was a lot of distortion with the StellaCam3 camera. Bright bands flickering and rolling up the screen. These bands were as bright as the star! The entire screen was fading and brightening at a slow frequency. On the tiny display on the camera, I could not clearly see the star in the non-integrated mode.
Seemed strange to me with such a bright target star... Despite fiddling with the Gain and the Gamma.
I wasn't too upset. I was off the path. It was a low probability event. It was treating the evening as a test. But still, it was a little discouraging to see such poor quality. And the distortion, wherever it is coming from, needs to be identified. This was the worst I had seen.
Got everything connected and working but there was a lot of distortion with the StellaCam3 camera. Bright bands flickering and rolling up the screen. These bands were as bright as the star! The entire screen was fading and brightening at a slow frequency. On the tiny display on the camera, I could not clearly see the star in the non-integrated mode.
Seemed strange to me with such a bright target star... Despite fiddling with the Gain and the Gamma.
I wasn't too upset. I was off the path. It was a low probability event. It was treating the evening as a test. But still, it was a little discouraging to see such poor quality. And the distortion, wherever it is coming from, needs to be identified. This was the worst I had seen.
Monday, February 21, 2011
cable arrived
I don't know if it arrived Friday or Monday but I found a package from Zengineering when I got home.
Now I can test it with our MallinCam Hyper Color camera...
Now I can test it with our MallinCam Hyper Color camera...
Sunday, February 20, 2011
slide scans
My sister is capturing her 3800 film slides via the slide scanner I gave her a few Christmas seasons back. She's been sending me samples.
Pukaskwa National Park, Lake Superior, 1991. Bear country.
Algoma Provincial Park, Lake Superior, 1989.
She really does have a great eye. Beautiful work.
Copyright © 2011. D. Nancarrow. All Rights Reserved.
Pukaskwa National Park, Lake Superior, 1991. Bear country.
Algoma Provincial Park, Lake Superior, 1989.
She really does have a great eye. Beautiful work.
Copyright © 2011. D. Nancarrow. All Rights Reserved.
Saturn and our Moon (Blue Mountains)
12:58 AM. Justed finished observing with Tony.
It was -9°C but felt like -16°C with the wind chill.
We viewed Saturn. C ring. Shadow on rings. Two moons nearby. Fairly good seeing. 18mm in C14. 3mm in TV101. Equatorial belt obvious. Could not see any mottling in the north hemisphere.
We viewed the Moon. With an adjustable polariser! I didn't know we had that! Spent time on Crisium. Picard and other large crater. Watch shadows lengthen. Enjoy the double peak complex in Langrenus.
Used Lunar Republic to ID the larger craters.
We were seeing down to 5 or 6 km craters.
Back to Saturn. 10mm in C14. Remarkably good.
Very clear! Horizon to horizon. The CSC was totally wrong.
Too bad the Moon was so bright.
Tony was cold and I was yawning.
The GBO roof continues to work flawlessly.
It was -9°C but felt like -16°C with the wind chill.
We viewed Saturn. C ring. Shadow on rings. Two moons nearby. Fairly good seeing. 18mm in C14. 3mm in TV101. Equatorial belt obvious. Could not see any mottling in the north hemisphere.
We viewed the Moon. With an adjustable polariser! I didn't know we had that! Spent time on Crisium. Picard and other large crater. Watch shadows lengthen. Enjoy the double peak complex in Langrenus.
Used Lunar Republic to ID the larger craters.
We were seeing down to 5 or 6 km craters.
Back to Saturn. 10mm in C14. Remarkably good.
Very clear! Horizon to horizon. The CSC was totally wrong.
Too bad the Moon was so bright.
Tony was cold and I was yawning.
The GBO roof continues to work flawlessly.
Saturday, February 19, 2011
ISS pass captured (Blue Mountains)
5:45 PM. I set up for ISS pass. Was hoping to record it with Denis's occultation rig and camcorder. Could not use the flip mirror on the TV 'scope. Made focussing a challenge...
7:53 PM. Tony and I observed ISS pass. Attempted video recording with StellaCam3 but the image was rather small in TV101 with SC3 focal reducer. Low and short.
I forgot to properly activate the camcorder. Doh!
Meanwhile, Tony watched in C14 at low power. We could see detail, some shape.
He did an afocal shot!
Photo by Tony. Sony point-and-shoot. f/2.8 at 1 sec. ISO 320. Exp. comp. +2.
I removed the reducer but could not reach focus at all.
We forgot to observe the NanoSail a few minutes later.
§
Once again this shows that (assuming we have good, accurate TLE data) that the GBO telescope and mount work well.
I'm looking forward to getting some stills and video over the spring and summer.
7:53 PM. Tony and I observed ISS pass. Attempted video recording with StellaCam3 but the image was rather small in TV101 with SC3 focal reducer. Low and short.
I forgot to properly activate the camcorder. Doh!
Meanwhile, Tony watched in C14 at low power. We could see detail, some shape.
He did an afocal shot!
Photo by Tony. Sony point-and-shoot. f/2.8 at 1 sec. ISO 320. Exp. comp. +2.
I removed the reducer but could not reach focus at all.
We forgot to observe the NanoSail a few minutes later.
§
Once again this shows that (assuming we have good, accurate TLE data) that the GBO telescope and mount work well.
I'm looking forward to getting some stills and video over the spring and summer.
Friday, February 18, 2011
brief observing (Blue Mountains)
We (Trevor, Tony, and I) tried to do a bit of observing before the bright Moon rose. I still had the StellaCam3 connected to the telescope.
It was cold and a little cloudy.
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This view is showing a lot of sky: approx. 1°9' x 0°56'. I must have moved the StellaCam over to the Tele Vue 101 'scope and reinstalled the focal reducer. The view is rotated (as I wasn't using the mirror). N is down and right; E is up and right. NGC 1977 is at the bottom-right of the image; NGC 1980 is near the top-left. You can see θ2 (theta-2) Orionis just about the bright centre of the nebula,
It was cold and a little cloudy.
§
This view is showing a lot of sky: approx. 1°9' x 0°56'. I must have moved the StellaCam over to the Tele Vue 101 'scope and reinstalled the focal reducer. The view is rotated (as I wasn't using the mirror). N is down and right; E is up and right. NGC 1977 is at the bottom-right of the image; NGC 1980 is near the top-left. You can see θ2 (theta-2) Orionis just about the bright centre of the nebula,
couldn't see the target (Blue Mountains)
Wanted to make a video recording of the (16) Psyche occultation. But the mag 12 star GSC 01275-1410 (aka 2UCAC 38564170) was so dim against the bright sky that I could not see it, visually, nor in the CCD camera view. It'd didn't help having the C14's aperture. It'd didn't help having the extremely accurate Paramount ME.
A few moments later, I could see stars on the monitor.
Maybe it's not a good idea to try for asteroid occultations when the Sun has just set...
§
The T-Point model for TheSky6 is off a little. Doesn't really matter for our visual astronomy activities. Perhaps we can refine it, or make a new one, that is much better. Then if I try a similar exercise, choosing a star without seeing it, I can trust that it will be in the field...
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The opposite is not necessarily true, that is, if I am interested in an occultation near sunrise. In darkness, I can acquire the star. Assuming I have good tracking and the camera can detect the star then let the recording happening.
A few moments later, I could see stars on the monitor.
Maybe it's not a good idea to try for asteroid occultations when the Sun has just set...
§
The T-Point model for TheSky6 is off a little. Doesn't really matter for our visual astronomy activities. Perhaps we can refine it, or make a new one, that is much better. Then if I try a similar exercise, choosing a star without seeing it, I can trust that it will be in the field...
§
The opposite is not necessarily true, that is, if I am interested in an occultation near sunrise. In darkness, I can acquire the star. Assuming I have good tracking and the camera can detect the star then let the recording happening.
serendipitous Sun (Blue Mountains)
Needed to focus the StellaCam3 in anticipation of the asteroid Psyche occultation. What to choose in daylight? Ah, the Sun, of course. After strapping on the white light filter, I targeted the Sun.
Ha! Look at that. I spotted sunspots!
§
That is spot 1158.
Ha! Look at that. I spotted sunspots!
§
That is spot 1158.
Thursday, February 17, 2011
I knew it I knew it I knew it I knew it
I knew I still had my old Map of the Moon! I found it! Yeah. Damn it.Rand McNally Map of the Moon and Map of the Planets.
Check out the price on the thing!
Inside it shows The Straight Wall. They also feature the Explorer I, Vanguard, and Jupiter-C rockets!
I was flying this thing in the 70s while I was in high school. But I don't remember where it came from or how I got it. Probably handed down from a grandparent. Oh! I found the copyright date: MCMLVIII. Ha ha.
I knew it! I knew I had it.
Wednesday, February 16, 2011
cable in transit
I heard from Alex, regarding my order.
Your Green Led Cable went out in the shipping run on Friday the 11th. International Shipping can take anywhere from 7-14 days... Thank you...Exciting. Looking forward to connecting it to our MallinCam.
Tuesday, February 15, 2011
a stitch in time
Well, I missed it. I had to do more than 9 stitches to re-affix the Velcro hook pad to the end of the elastic dew wrap strap. Shoddy work by Kendrick. A lemon?
The 2" heater for large eyepieces is ready for service again. Just in time for the CAO...
The 2" heater for large eyepieces is ready for service again. Just in time for the CAO...
so what are they for?
There is something rather curious about SkyTools 3 and Visual Sky Simulation (VSS) window. Greg says it is for visual astronomers. The imagers shouldn't use it. Of course, with the 3 main panels, the Naked Eye, Finder, and Eyepiece views, it is clearly for people to get to an object quickly. And while he mixes his terminology a bit, Greg is, I believe, trying to preach a new way of getting to a target versus the old, classic method of star hopping (in little jumps). He wants you to use the 3 panels to:
This is not hopping. This is warping!
The only gotcha that I see to all this is that I don't think enough stars are showing in some of the panels.
The VSS window is completely dynamic! Greg is trying, as accurately as possible (he purports), to present how you will see the sky at each of these levels. He takes into consideration atmospheric extinction, Moonlight, your iris size, and the quality of your observing location sky. "Many variables that have to be tamed." And, curiously, he offers no controls here. He's the first to say, if you wanna change the atlas appearance, you need to use the Interactive Atlas instead. But then, no more 3 panels.
Maybe it is because I'm an experienced observer but I can see way more stars than he shows in the VSS. See the irony? The view he's encouraging us to use, as the New Way to rapidly get to targets, abandon your ancient star hopping techniques, burn your All About Telescopes, use the Visual Sky Simulation window, he is making broad assumptions on, completely automating the generation processes, to the point where I (and others) can't use it. Invariably, when I look at the Finder panel, it is empty.
Tell me that's not intimidating to rookies.
I found a way to hack it. Set your location's Sky brightness at zenith setting to a crazy high value. I live in Toronto. My porch overlooks the street with cobra lights and oblivious neighbours. But when I set it to a Bortle Scale value to 1 (i.e. 21.90 mag/arcsec2), I see a better representation of my urban skies.
That's better.
- face in the right direction to begin with
- centre on the object with the finder
- view the object in the telescope
- face in the right direction to begin with (Naked Eye panel)
- zoom in a little (not too much)
- note where the finder is positioned roughly
- aim your telescope in this general area
- transition to the Finder panel comparing views
- centre on the object with the finder (Finder panel)
- use the reference stars and objects to verify your location (using the outer circle)
- centre the finder on target, i.e. shift the telescope a little
- transition to the Eyepiece panel comparing views (using the inner circle)
- view the object in the telescope (Eyepiece panel)
- use the reference stars and objects to verify your location
- shift the telescope a little, if nec.
- rotate the field of view circle, if nec.
This is not hopping. This is warping!
The only gotcha that I see to all this is that I don't think enough stars are showing in some of the panels.
The VSS window is completely dynamic! Greg is trying, as accurately as possible (he purports), to present how you will see the sky at each of these levels. He takes into consideration atmospheric extinction, Moonlight, your iris size, and the quality of your observing location sky. "Many variables that have to be tamed." And, curiously, he offers no controls here. He's the first to say, if you wanna change the atlas appearance, you need to use the Interactive Atlas instead. But then, no more 3 panels.
Maybe it is because I'm an experienced observer but I can see way more stars than he shows in the VSS. See the irony? The view he's encouraging us to use, as the New Way to rapidly get to targets, abandon your ancient star hopping techniques, burn your All About Telescopes, use the Visual Sky Simulation window, he is making broad assumptions on, completely automating the generation processes, to the point where I (and others) can't use it. Invariably, when I look at the Finder panel, it is empty.
Tell me that's not intimidating to rookies.
I found a way to hack it. Set your location's Sky brightness at zenith setting to a crazy high value. I live in Toronto. My porch overlooks the street with cobra lights and oblivious neighbours. But when I set it to a Bortle Scale value to 1 (i.e. 21.90 mag/arcsec2), I see a better representation of my urban skies.
That's better.
fake 'scope
Here are the details of the "telescope" and "eyepiece" I put into SkyTools3 to help me simulate the view through the polar axis finder scope.
aperture: 20mm
telescope focal length: 108mm
eyepiece focal length: 18mm
apparent field of view: 48°
The aperture I found noted on a couple of web sites. And I measured it with my ruler.
The magnification number (6) and true field of view (8) also came from the web. I'm hoping they are correct.
I took the polar axis scope apart, that is I removed the eyepiece from the little scope shaft. Spotted the reticule cross hair plate thing. Sitting in a field stop. Ah ha! That field stop was 15mm in diameter.
I calculated the telescope focal length by multiplying the field stop by the magic number 57.3 (found at Tele Vue) and divided by the TFOV: 108mm (rounding up).
AFOV comes from the product of the mag and TFOV.
While I was goofing around with the tiny telescope, quite by accident I beamed the clear image of the reticule onto my desk. So I grabbed a piece of paper and did a rough tracing. Then I measured the inner circle to the outer field: 5 times. Like what I guessed yesterday.
So, I'm pretty happy with all these numbers. It's close enough for my improved polar alignments.
The key thing now is that I can know where the NCP is, in advance.
§
Huh.
You can still buy it... In a kit. Looks like there's bits for different models of telescopes. Not cheap.
aperture: 20mm
telescope focal length: 108mm
eyepiece focal length: 18mm
apparent field of view: 48°
The aperture I found noted on a couple of web sites. And I measured it with my ruler.
The magnification number (6) and true field of view (8) also came from the web. I'm hoping they are correct.
I took the polar axis scope apart, that is I removed the eyepiece from the little scope shaft. Spotted the reticule cross hair plate thing. Sitting in a field stop. Ah ha! That field stop was 15mm in diameter.
I calculated the telescope focal length by multiplying the field stop by the magic number 57.3 (found at Tele Vue) and divided by the TFOV: 108mm (rounding up).
AFOV comes from the product of the mag and TFOV.
While I was goofing around with the tiny telescope, quite by accident I beamed the clear image of the reticule onto my desk. So I grabbed a piece of paper and did a rough tracing. Then I measured the inner circle to the outer field: 5 times. Like what I guessed yesterday.
So, I'm pretty happy with all these numbers. It's close enough for my improved polar alignments.
The key thing now is that I can know where the NCP is, in advance.
§
Huh.
You can still buy it... In a kit. Looks like there's bits for different models of telescopes. Not cheap.
math homework
Eeewww.
Just reviewing all the basic math calculations... Remember to treat everything in consistent units, millimetres or inches, whichever. The slash symbol (/) is used in these notes of course to mean divide or division.
One of the common ones people want to know. "What power is that?"
eyepiece power or magnification
= telescope focal length / eyepiece focal length
Simple calculation you can often do quickly, crudely in the field. E.g. 2000 mm SCT with a 25 mm eyepiece is 80x (or 80 times or 80 power).
Focal length of a telescope is fairly easy to calculate for a refractor but gets increasingly complicated with reflectors and compounds. Eyepiece focal length is hopefully printed or stamped on the ocular itself. You can't tell just by looking, in general.
When I started serious observing, I needed to know how much an eyepiece-telescope combination showed of the sky. It was startling to finally, accurately calculate it.
eyepiece true field of view
= eyepiece apparent field of view / magnification
Now this one can be a little tricky to do, especially with older eyepieces, where the information was not sometimes published. In modern times, an eyepiece company will tell you all the specs. E.g. a Tele Vue 9mm (focal length) Type 6 Nagler has an AFOV of 82 degrees (°). If used at 222x, then the TFOV is 0.37°. I.e. you're seeing less than ½ a degree of sky. That's a circle no bigger than the disk of the Moon.
If you cannot determine the AFOV of an eyepiece, you can compute it "backwards" by doing "drift timings" with your telescope (assuming you have all the other numbers and you're OK with doing some trig!). That's a discussion for another day.
There is another way to calculate TFOV but it requires you know the eyepiece field stop diameter size.
eyepiece true field of view
= ( eyepiece field stop / telescope focal length ) * 57.3
Another interesting number is exit pupil. That's the size of the light cone emitted from the eyepiece. If it is significantly large than your iris (taking into account your dark adaptation, age, and other factors), you might experience a degraded image. Conversely, an extremely small exit cone is simply hard to see. You have to bob and weave to catch the image.
exit pupil
= telescope aperture / magnification
Aperture is the size of the opening at the "front" of the telescope. Often this is simply the clear glass in a refractor or the size of the mirror in a reflector or compound.
You would calculate exit pupil values when eyepiece shopping to ensure you don't get something that's inappropriate for your telescope configuration and your visual acuity.
If you want to know the "speed" of your telescope, then you need the focal ratio number.
focal ratio number
= telescope focal length / telescope aperture
Simply put, how long is it compared to how wide. This is usually shown as f followed by a slash and a number, e.g. f/5. The classic 8 inch (203 mm aperture) telescope with a 2000 mm focal length is an f/10 'scope. If you have experience with SLR cameras and interchangeable lenses, then you know something of aperture and lens speed.
Years ago I built an Excel spreadsheet to crunch all these numbers. Then I redid that in my Psion Sheet application so I had all the numbers in my pocket.
Found a handy calculator (the TEC) on the web too. There are lots. But the TEC let's you load in a set of eyepieces vs. one at a time.
Just reviewing all the basic math calculations... Remember to treat everything in consistent units, millimetres or inches, whichever. The slash symbol (/) is used in these notes of course to mean divide or division.
One of the common ones people want to know. "What power is that?"
eyepiece power or magnification
= telescope focal length / eyepiece focal length
Simple calculation you can often do quickly, crudely in the field. E.g. 2000 mm SCT with a 25 mm eyepiece is 80x (or 80 times or 80 power).
Focal length of a telescope is fairly easy to calculate for a refractor but gets increasingly complicated with reflectors and compounds. Eyepiece focal length is hopefully printed or stamped on the ocular itself. You can't tell just by looking, in general.
When I started serious observing, I needed to know how much an eyepiece-telescope combination showed of the sky. It was startling to finally, accurately calculate it.
eyepiece true field of view
= eyepiece apparent field of view / magnification
Now this one can be a little tricky to do, especially with older eyepieces, where the information was not sometimes published. In modern times, an eyepiece company will tell you all the specs. E.g. a Tele Vue 9mm (focal length) Type 6 Nagler has an AFOV of 82 degrees (°). If used at 222x, then the TFOV is 0.37°. I.e. you're seeing less than ½ a degree of sky. That's a circle no bigger than the disk of the Moon.
If you cannot determine the AFOV of an eyepiece, you can compute it "backwards" by doing "drift timings" with your telescope (assuming you have all the other numbers and you're OK with doing some trig!). That's a discussion for another day.
There is another way to calculate TFOV but it requires you know the eyepiece field stop diameter size.
eyepiece true field of view
= ( eyepiece field stop / telescope focal length ) * 57.3
Another interesting number is exit pupil. That's the size of the light cone emitted from the eyepiece. If it is significantly large than your iris (taking into account your dark adaptation, age, and other factors), you might experience a degraded image. Conversely, an extremely small exit cone is simply hard to see. You have to bob and weave to catch the image.
exit pupil
= telescope aperture / magnification
Aperture is the size of the opening at the "front" of the telescope. Often this is simply the clear glass in a refractor or the size of the mirror in a reflector or compound.
You would calculate exit pupil values when eyepiece shopping to ensure you don't get something that's inappropriate for your telescope configuration and your visual acuity.
If you want to know the "speed" of your telescope, then you need the focal ratio number.
focal ratio number
= telescope focal length / telescope aperture
Simply put, how long is it compared to how wide. This is usually shown as f followed by a slash and a number, e.g. f/5. The classic 8 inch (203 mm aperture) telescope with a 2000 mm focal length is an f/10 'scope. If you have experience with SLR cameras and interchangeable lenses, then you know something of aperture and lens speed.
Years ago I built an Excel spreadsheet to crunch all these numbers. Then I redid that in my Psion Sheet application so I had all the numbers in my pocket.
Found a handy calculator (the TEC) on the web too. There are lots. But the TEC let's you load in a set of eyepieces vs. one at a time.
old dog
There ya go. Learn somethin' every day.
For some reason, I thought the gap between Polaris and the North Celestial Pole was increasing. Nope.
The polar axis 'scope has the inner circle etched at 48 arc-minutes. It was made in the late 80s or early 90s.
I found a little table in the EQ6 documentation.
So the 40' to 41' I was getting last night was in fact correct.
This made me go back and check if all that work I put into a custom Polaris reference guide plate was correct. Yes. But now I see it is out of date again! Ha ha.
For some reason, I thought the gap between Polaris and the North Celestial Pole was increasing. Nope.
The polar axis 'scope has the inner circle etched at 48 arc-minutes. It was made in the late 80s or early 90s.
I found a little table in the EQ6 documentation.
year | xxxxx | distance in arc-min |
| 2000 | 45 | |
| 2002 | 44 | |
| 2004 | 44 | |
| 2006 | 43 | |
| 2008 | 43 | |
| 2010 | 42 | |
| 2012 | 42 | |
| 2014 | 41 | |
| 2016 | 40 | |
| 2018 | 40 | |
| 2020 | 39 |
So the 40' to 41' I was getting last night was in fact correct.
This made me go back and check if all that work I put into a custom Polaris reference guide plate was correct. Yes. But now I see it is out of date again! Ha ha.
polar specs
Found a note on a store site about the Vixen polar axis 'scope. Now, it is specifically for the GPD2 model...
"Polar Axis Scope:
6x20mm
wide 8 degree field of view"
Seems to match my numbers. I tuned SkyTools for this.
"Polar Axis Scope:
6x20mm
wide 8 degree field of view"
Seems to match my numbers. I tuned SkyTools for this.
bad seeing (Toronto)
I wasn't expecting a lot. Still, I thought I'd meet with a bit more success. It proved to be a bit frustrating this session. Atmospheric conditions? High wind (er, high winds high up)? My eyes? Observing over hot rooftops and chimneys? All of the above?
12:24 AM. I tried my hand-made Bahtinov focus-mask. One word: amazing! It's true. It is outstanding. Unmistakable. I'm a convert. I'm a disciple. It makes it so easy to focus! There is no doubt now when focusing. This will be so useful for photography.
Now, all that said, it's a bit of a hassle with the dew shield installed. I had to flex the disk and wriggle it down the shield. It is partly because the plastic shield is tapered at the front. It is also slightly tighter on the inside now that I've installed the flock paper.
I wonder if it might be easier to do focusing first, before you've installed the dew shield. Will need to noodle on this a bit. If a focus change is required more than once in a session, it will be fiddly. Perhaps this is an advantage to "draping" the mask on the front of the 'scope. Huh. I could try it in front of the dew shield...
Regardless, it was astonishingly easy to focus.
OK. Official observing time now!
Looked through the large gap in the trees to the west. Orion was setting, Sirius was just above the treeline. Monoceros should be above. SkyTools3 suggested double star J 717 A. I tried starhopping from Sirius via β (beta) Mon but couldn't do it in time. Struggled a bit with the ST3 software; refused to use Stellarium to help. Damn faint stars in The Unicorn. In the end, it was too low a target. OK. Something high up then!
I'm still really struggling with how ST3 presents the "telescope" 3 panel view. This is probably the view I should use when starhopping but, tonight, for me, it is useless. It is not showing nearly the number of stars I need. I abandoned it and just worked with the Interactive Atlas and Context Viewer windows.
I heard a different note from the mount motor. Normally, when the clutch is disengaged, there is a light chatter from the motor. When it is under load, the chatter goes away, leaving only a whir or soft electric grind sound. Now it was making a chattering noise all the time. It made me think, at first, that the clutch was not tight. It was engaged. I wondered if it was increased loading due to the cold temperature. Made me wonder at the condition of the grease in the old beast. Maybe I should freshen it up...
1:37. I tried to split SAO 16732, aka Σ3125, in Ursa Minor, off the bottom edge of the pot. Successfully starhopped to the target starting at γ (gamma) UMi. ST3 showed a gaggle of stars, along the route, around RA 15 14 39, dec +68 21 28, but I didn't see anything. I also saw the wide double Σ1958 nearby (mag 9.58 and 10.3 stars about 29.6" apart). But I could not split 3125. ST3 said they were mag 10.31 and 10.3 and 2.1" apart. Ooh. Tight. I tried the baader planetarium 36mm, Celestron 26mm, and Tele Vue 9mm eyepieces (56x, 77x, and +200x respectively) without luck.
1:47. Viewed Saturn. It was delicious in the baader Hyperion-Aspherical ocular with its wide field. The planet was very bright. Cloud bands could be easily seen. The northern region seemed a homogeneous tan. Couldn't pick off any variations.
Noted a medium bright point just over 1 ring-width to the right, a very faint point less than 1 rw on the left, and a very bright point further left. ST3 informed me they were Rhea (east), Dione, and Titan (west). A couple of bright stars below.
Dione came and went. As the seeing changed, I'd lose sight of the mag 10.5 moon. It was easy to spot with the Tele Vue Nagler Type 6.
My feet were a little sore. I wanted to sit at the eyepiece. I hadn't done so with any of the targets so far (expect when working with Polaris). It was a tight fit, given the spot I had selected for the the tripod, beside the BBQ and the tripod. I had to wriggle up to the mount and then pull the chair in behind me. But it proved futile. Kept touching the tripod with my left leg. The chair was very slippy with ski pants. So I kept sliding forward.
That reminded me that I never got round to the adding the sawdust layer to the seat! Damn. Shoulda done it as soon as I collected the stuff from the CAO last summer! Now I had no idea where the Spar Varish was... Loser.
My feet were bothering me. I needed a place to sit. Ideally, a chair at the kitchen table would have been perfect. When I clear it of renovation bits and tools, it will be great for this. I pulled a lawn chair into the kitchen and plopped down. Aah. Warmed up a light as I played with ST3.
Kept returning to Saturn. It wasn't a great view. It was almost impossible to see the Cassini Division. I tried and tried to tag Enceladus and Tethys on the right side of the rings. The 222 magnification was a little soft.
2:49. I split HD 129600 aka Σ1871 in Boötes. But it was not easy. Yes, it was another tight double at 2" separation but probably accomplished due to their brightness. I thought them equal brightness and a bluish colour, both, similar. ST3 said the mags were 7.26 and 8.16.
I wondered if the conditions were off. Was the seeing poor?
And then the Velcro end on the eyepiece heater strap broke off. Damn. It finally went.
Took another look at Saturn and then threw in towel.
And, finally, did my "quick" shutdown. Removed all the wires and tossed them in a chair. Dismounted the OTA and laid it in the kitchen. Removed the mount and laid it in the kitchen. Brought the tripod, intact, extended from the porch. Did not knock anything over. Done.
Thought briefly about leaving the 'scope outside at ambient temperature to again speed future use.
Trundled to bed.
§
Only 5 objects were viewed for the evening, including Polaris. Huh. Not a lot.
The view of Saturn was a little murky.
The focus-mask testing proved the highlight of the evening!
Oh. And the tracking was bang on. Despite the burden on the motor. That was pretty cool.
12:24 AM. I tried my hand-made Bahtinov focus-mask. One word: amazing! It's true. It is outstanding. Unmistakable. I'm a convert. I'm a disciple. It makes it so easy to focus! There is no doubt now when focusing. This will be so useful for photography.
Now, all that said, it's a bit of a hassle with the dew shield installed. I had to flex the disk and wriggle it down the shield. It is partly because the plastic shield is tapered at the front. It is also slightly tighter on the inside now that I've installed the flock paper.
I wonder if it might be easier to do focusing first, before you've installed the dew shield. Will need to noodle on this a bit. If a focus change is required more than once in a session, it will be fiddly. Perhaps this is an advantage to "draping" the mask on the front of the 'scope. Huh. I could try it in front of the dew shield...
Regardless, it was astonishingly easy to focus.
OK. Official observing time now!
Looked through the large gap in the trees to the west. Orion was setting, Sirius was just above the treeline. Monoceros should be above. SkyTools3 suggested double star J 717 A. I tried starhopping from Sirius via β (beta) Mon but couldn't do it in time. Struggled a bit with the ST3 software; refused to use Stellarium to help. Damn faint stars in The Unicorn. In the end, it was too low a target. OK. Something high up then!
I'm still really struggling with how ST3 presents the "telescope" 3 panel view. This is probably the view I should use when starhopping but, tonight, for me, it is useless. It is not showing nearly the number of stars I need. I abandoned it and just worked with the Interactive Atlas and Context Viewer windows.
I heard a different note from the mount motor. Normally, when the clutch is disengaged, there is a light chatter from the motor. When it is under load, the chatter goes away, leaving only a whir or soft electric grind sound. Now it was making a chattering noise all the time. It made me think, at first, that the clutch was not tight. It was engaged. I wondered if it was increased loading due to the cold temperature. Made me wonder at the condition of the grease in the old beast. Maybe I should freshen it up...
1:37. I tried to split SAO 16732, aka Σ3125, in Ursa Minor, off the bottom edge of the pot. Successfully starhopped to the target starting at γ (gamma) UMi. ST3 showed a gaggle of stars, along the route, around RA 15 14 39, dec +68 21 28, but I didn't see anything. I also saw the wide double Σ1958 nearby (mag 9.58 and 10.3 stars about 29.6" apart). But I could not split 3125. ST3 said they were mag 10.31 and 10.3 and 2.1" apart. Ooh. Tight. I tried the baader planetarium 36mm, Celestron 26mm, and Tele Vue 9mm eyepieces (56x, 77x, and +200x respectively) without luck.
1:47. Viewed Saturn. It was delicious in the baader Hyperion-Aspherical ocular with its wide field. The planet was very bright. Cloud bands could be easily seen. The northern region seemed a homogeneous tan. Couldn't pick off any variations.
Noted a medium bright point just over 1 ring-width to the right, a very faint point less than 1 rw on the left, and a very bright point further left. ST3 informed me they were Rhea (east), Dione, and Titan (west). A couple of bright stars below.
Dione came and went. As the seeing changed, I'd lose sight of the mag 10.5 moon. It was easy to spot with the Tele Vue Nagler Type 6.
My feet were a little sore. I wanted to sit at the eyepiece. I hadn't done so with any of the targets so far (expect when working with Polaris). It was a tight fit, given the spot I had selected for the the tripod, beside the BBQ and the tripod. I had to wriggle up to the mount and then pull the chair in behind me. But it proved futile. Kept touching the tripod with my left leg. The chair was very slippy with ski pants. So I kept sliding forward.
That reminded me that I never got round to the adding the sawdust layer to the seat! Damn. Shoulda done it as soon as I collected the stuff from the CAO last summer! Now I had no idea where the Spar Varish was... Loser.
My feet were bothering me. I needed a place to sit. Ideally, a chair at the kitchen table would have been perfect. When I clear it of renovation bits and tools, it will be great for this. I pulled a lawn chair into the kitchen and plopped down. Aah. Warmed up a light as I played with ST3.
Kept returning to Saturn. It wasn't a great view. It was almost impossible to see the Cassini Division. I tried and tried to tag Enceladus and Tethys on the right side of the rings. The 222 magnification was a little soft.
2:49. I split HD 129600 aka Σ1871 in Boötes. But it was not easy. Yes, it was another tight double at 2" separation but probably accomplished due to their brightness. I thought them equal brightness and a bluish colour, both, similar. ST3 said the mags were 7.26 and 8.16.
I wondered if the conditions were off. Was the seeing poor?
And then the Velcro end on the eyepiece heater strap broke off. Damn. It finally went.
Took another look at Saturn and then threw in towel.
And, finally, did my "quick" shutdown. Removed all the wires and tossed them in a chair. Dismounted the OTA and laid it in the kitchen. Removed the mount and laid it in the kitchen. Brought the tripod, intact, extended from the porch. Did not knock anything over. Done.
Thought briefly about leaving the 'scope outside at ambient temperature to again speed future use.
Trundled to bed.
§
Only 5 objects were viewed for the evening, including Polaris. Huh. Not a lot.
The view of Saturn was a little murky.
The focus-mask testing proved the highlight of the evening!
Oh. And the tracking was bang on. Despite the burden on the motor. That was pretty cool.
porch observatory
Finished all my prep.
The power cord was threaded outside through the kitchen window.
The Celestron 8" Schmidt-Cassegrain tube was installed atop the Vixen Super Polaris mount. I put the plastic dew cap in place.
Finder scope installed and aligned.
The dew heaters were installed and powered. The Velcro end on the eyepiece strap was a little flimsy, on its last threads... I hoped the end bit wouldn't fly off the porch in a snow bank.
The mount already felt a little stiff to move about, as the temperature dropped.
Netbook was in the kitchen staying warm, custom observing list ready.
I had suited up with ski pants and 5 layers on the torso.
I should come up with a name... The Overlook? Ha ha ha!
The power cord was threaded outside through the kitchen window.
The Celestron 8" Schmidt-Cassegrain tube was installed atop the Vixen Super Polaris mount. I put the plastic dew cap in place.
Finder scope installed and aligned.
The dew heaters were installed and powered. The Velcro end on the eyepiece strap was a little flimsy, on its last threads... I hoped the end bit wouldn't fly off the porch in a snow bank.
The mount already felt a little stiff to move about, as the temperature dropped.
Netbook was in the kitchen staying warm, custom observing list ready.
I had suited up with ski pants and 5 layers on the torso.
I should come up with a name... The Overlook? Ha ha ha!
Monday, February 14, 2011
aligning with SkyTools
During (visual) observing session preparation with the Celestron-Vixen Super Polaris mount, I usually just put Polaris somewhere inside the polar 'scope field and leave it at that. I'm not doing photography (or I haven't so far) thus a highly accurate alignment isn't necessary.
However I have noticed on some occasions that my tracking is spot on; other times not. Mildly annoying. If I wasn't thorough or careful, I supposed the alignment could be off by a degree or so.
Suddenly, I wondered if I could improve on it with the use of SkyTools 3. I added Polaris to the observing list!
If I always include Polaris, then I can show it on a built-in sky atlas display. With the North Star on the electronic chart shown specifically at the time of set-up, I'd be able see the relative position of the north celestial pole (NCP) as well as the distance between (ha ha, position angle and separation). I still have a bad taste in my mouth with the low bandwidth way of using the little paper star wheel guide thing.
Then, it occurred me that it would be helpful to simulate the field of view as presented by the built-in polar axis 'scope. I did a bit of web stumbling to try to get that number but couldn't turn up anything. I thought it roughly same as my cheapo binoculars or the old 6x30 finder scope. So about 7°.
I looked closely at the reticule again. I know the radius of the inner circle is 48 arc-minutes. The inner circle appeared to consume about 1/5th of the FOV which roughly makes the field 500' in diameter. Quickly crunched some numbers in a spreadsheet. Then made a "fake" refractor telescope in ST3: 51mm aperture with a 250mm focal length with a 40mm eyepiece sporting a 60° apparent field of view. It approximated the power and field of the little pole 'scope.
I turned on the "flipped" option but not the "mirrored." A little foggy about that again but I knew I could apply that later.
Opened up the Interactive Atlas on Polaris. Set the time to Now. The Little Dipper was off to the right, almost horizontal, matching how I saw it in the sky, naked eye.
Activated the Context Viewer. Told it to use the new "Vixen Polar Scope" with the matching eyepiece. Switched the Mirror Diagonal option on. Dragged the orientation handle so that west was straight up. Voila. Rotated view with δ (delta) UMi off to the top-left!
OK. Where's NCP now? I wondered. I popped into the View Controls and looked for a little NCP cross hair option... Didn't see anything so I set the Coordinate Grid to Equatorial Apparent with the Fine option. Ugh. Changed the colour from white to red in the Chart Preferences. It would do, even though the grid leaves a donut hole in the middle. So, now I knew that the NCP was a bit to the left of Polaris and, happily, at that moment, almost perfectly horizontal.
How far? I zoomed in. Then right-clicked in the donut hole and chose the Angular Measure option. Hovered on Polaris. Curiously, I found that NCP and Polaris are about 40' apart! Hey. Not 48, like what the reticule is marked at. That's weird, I thought we were moving further away...
Anyway. It was working. I wanted to know where NCP was in relation to α (alpha) Ursae Minoris presented in a way that would match the tiny polar axis telescope. I set the mount so that it was aimed a bit left of the North Star.
We'll see how it holds up.
However I have noticed on some occasions that my tracking is spot on; other times not. Mildly annoying. If I wasn't thorough or careful, I supposed the alignment could be off by a degree or so.
Suddenly, I wondered if I could improve on it with the use of SkyTools 3. I added Polaris to the observing list!
If I always include Polaris, then I can show it on a built-in sky atlas display. With the North Star on the electronic chart shown specifically at the time of set-up, I'd be able see the relative position of the north celestial pole (NCP) as well as the distance between (ha ha, position angle and separation). I still have a bad taste in my mouth with the low bandwidth way of using the little paper star wheel guide thing.
Then, it occurred me that it would be helpful to simulate the field of view as presented by the built-in polar axis 'scope. I did a bit of web stumbling to try to get that number but couldn't turn up anything. I thought it roughly same as my cheapo binoculars or the old 6x30 finder scope. So about 7°.
I looked closely at the reticule again. I know the radius of the inner circle is 48 arc-minutes. The inner circle appeared to consume about 1/5th of the FOV which roughly makes the field 500' in diameter. Quickly crunched some numbers in a spreadsheet. Then made a "fake" refractor telescope in ST3: 51mm aperture with a 250mm focal length with a 40mm eyepiece sporting a 60° apparent field of view. It approximated the power and field of the little pole 'scope.
I turned on the "flipped" option but not the "mirrored." A little foggy about that again but I knew I could apply that later.
Opened up the Interactive Atlas on Polaris. Set the time to Now. The Little Dipper was off to the right, almost horizontal, matching how I saw it in the sky, naked eye.
Activated the Context Viewer. Told it to use the new "Vixen Polar Scope" with the matching eyepiece. Switched the Mirror Diagonal option on. Dragged the orientation handle so that west was straight up. Voila. Rotated view with δ (delta) UMi off to the top-left!
OK. Where's NCP now? I wondered. I popped into the View Controls and looked for a little NCP cross hair option... Didn't see anything so I set the Coordinate Grid to Equatorial Apparent with the Fine option. Ugh. Changed the colour from white to red in the Chart Preferences. It would do, even though the grid leaves a donut hole in the middle. So, now I knew that the NCP was a bit to the left of Polaris and, happily, at that moment, almost perfectly horizontal.
How far? I zoomed in. Then right-clicked in the donut hole and chose the Angular Measure option. Hovered on Polaris. Curiously, I found that NCP and Polaris are about 40' apart! Hey. Not 48, like what the reticule is marked at. That's weird, I thought we were moving further away...
Anyway. It was working. I wanted to know where NCP was in relation to α (alpha) Ursae Minoris presented in a way that would match the tiny polar axis telescope. I set the mount so that it was aimed a bit left of the North Star.
We'll see how it holds up.
getting ready for the finish
Yesterday I had noted that the Clear Sky Chart for Monday night (into Tuesday morning) looked good. Very good. Dark blue cubes for the cloud cover and medium blue for the transparency. A rare February opportunity that I could actually partake of. Got an itch...
For a while now, I have been considering a little experiment. After the observing session, I did not want to do a full tear-down. Since I'm not regularly transporting my 'scope somewhere different (like I do in the summer) I could leave gear partly assembled, leaving bits near the porch, in a standby state. Not exactly like hauling it completely intact into my garage at the old place (although that was not without issues). Anyway, in an effort to help me possibly observe more, be happier, speed set-up and tear-down time in the future, I wanted to try things a bit differently.
A subtle piece to this was only bring the necessary items to the kitchen for staging. My observing session back on 17 Jan made for a very crowded kitchen. I didn't need the huge tripod bag. I didn't need the various cases, once empty. These I would keep in their normal storage location in the bedroom. The other part, of course, at the end of the session, was to keep stuff near the porch, but still out of the way. Ideally, around and on the end of the kitchen table would serve as the temporary bay.
The more I thought about the clear evening sky prediction, the more I activities I found to do.
I could test the recently completed Bahtinov focus-mark. I had cut the outer edge to fit inside the C8 OTA and added a little knob to extract it. It was ready to go. It would be good to see if it worked as well as predicted.
I also could shoot a photo of the set-up on the porch, something I had forgotten to do in January, the first official telescope run at the new place.
At the same time, I kept catching myself.
I considered a test broadcast on Night Skies Network with the MallinCam. But I got my wires crossed on this, somehow. I thought I couldn't proceed, without the recently ordered cable. When in fact I had everything needed to operate the camera and capture video. Oops. The cable is only for controlling the camera, adjusting settings, remotely. Alas, it would have complicated set-up. And I was already on the edge of not proceeding.
I also thought about shooting a video of a double star drift to use with Ed's BinStar software. Again I was confuddled. I rejected the MallinCam because of my cable dilemma. Flawed logic, yes, I know. So I considered the StellaCam in Denis's kit. But a real stumbling block there is extracting video from the camcorder. It requires FireWire. Too many unknowns that I did not have the energy to resolve.
Tonight would also allow full testing of the new deep red LED flashlight head lamp thing.
Finally, if I could stay up long enough, if I could get a decent angle through the web of dark branches, I could steal more views of Saturn.
Red lights on. Red film on monitors and netbook. Little red film piece on digital camera display. Red keyboard light installed.
Started hauling gear to the porch. Including the 8", to cool. Had my adjustable height chair, the Big DOC, this time.
Grabbed the digital voice recorder and checked the power level. 3 of 4 bars. Popped the AAA batteries into charger. And then suddenly thought twice about it. The neighbours will really talk if they hear me mumbling away in the middle of the winter on the porch at 3:00 AM. Readied the paper notepad and a pencil instead.
As the clouds moved out, I pondered that it was not a great night for a variety of targets. With a gibbous Moon, deep sky objects would be out-of-bounds. I considered some double star viewing. And another look at Saturn, of course. I built a list in SkyTools 3 Pro starting with the automatic generator tool. And as I did my slow staged progressive set-up after dinner, I manually added planets.
For a while now, I have been considering a little experiment. After the observing session, I did not want to do a full tear-down. Since I'm not regularly transporting my 'scope somewhere different (like I do in the summer) I could leave gear partly assembled, leaving bits near the porch, in a standby state. Not exactly like hauling it completely intact into my garage at the old place (although that was not without issues). Anyway, in an effort to help me possibly observe more, be happier, speed set-up and tear-down time in the future, I wanted to try things a bit differently.
A subtle piece to this was only bring the necessary items to the kitchen for staging. My observing session back on 17 Jan made for a very crowded kitchen. I didn't need the huge tripod bag. I didn't need the various cases, once empty. These I would keep in their normal storage location in the bedroom. The other part, of course, at the end of the session, was to keep stuff near the porch, but still out of the way. Ideally, around and on the end of the kitchen table would serve as the temporary bay.
The more I thought about the clear evening sky prediction, the more I activities I found to do.
I could test the recently completed Bahtinov focus-mark. I had cut the outer edge to fit inside the C8 OTA and added a little knob to extract it. It was ready to go. It would be good to see if it worked as well as predicted.
I also could shoot a photo of the set-up on the porch, something I had forgotten to do in January, the first official telescope run at the new place.
At the same time, I kept catching myself.
I considered a test broadcast on Night Skies Network with the MallinCam. But I got my wires crossed on this, somehow. I thought I couldn't proceed, without the recently ordered cable. When in fact I had everything needed to operate the camera and capture video. Oops. The cable is only for controlling the camera, adjusting settings, remotely. Alas, it would have complicated set-up. And I was already on the edge of not proceeding.
I also thought about shooting a video of a double star drift to use with Ed's BinStar software. Again I was confuddled. I rejected the MallinCam because of my cable dilemma. Flawed logic, yes, I know. So I considered the StellaCam in Denis's kit. But a real stumbling block there is extracting video from the camcorder. It requires FireWire. Too many unknowns that I did not have the energy to resolve.
Tonight would also allow full testing of the new deep red LED flashlight head lamp thing.
Finally, if I could stay up long enough, if I could get a decent angle through the web of dark branches, I could steal more views of Saturn.
Red lights on. Red film on monitors and netbook. Little red film piece on digital camera display. Red keyboard light installed.
Started hauling gear to the porch. Including the 8", to cool. Had my adjustable height chair, the Big DOC, this time.
Grabbed the digital voice recorder and checked the power level. 3 of 4 bars. Popped the AAA batteries into charger. And then suddenly thought twice about it. The neighbours will really talk if they hear me mumbling away in the middle of the winter on the porch at 3:00 AM. Readied the paper notepad and a pencil instead.
As the clouds moved out, I pondered that it was not a great night for a variety of targets. With a gibbous Moon, deep sky objects would be out-of-bounds. I considered some double star viewing. And another look at Saturn, of course. I built a list in SkyTools 3 Pro starting with the automatic generator tool. And as I did my slow staged progressive set-up after dinner, I manually added planets.
tail end
Caught the tail end of York University's Observatory webcast. Eric reminded us of their usual Monday night astronomy show on astronomy.fm with chatroom on the observatory page. Saw a few RASCals there. I just lurked.
lots of junk
While reading about the Nanosail at SpaceFlightNow, I stumbled across something about space junk. I learned the military is tracking about 16,000 objects larger than 4 inches circling Earth. Obviously, even small debris moving at high speeds can pose serious threats to active spacecraft.
to insert
I'm moving ahead with the plan to have the focus-mask sit just inside the tube of the Celestron 8-inch SCT.
I had wondered if it would make a difference where the mask was, in front of the objective. But I'm seeing that some designs (including those by Spike-a) have a donut hole in the middle so the mask can fit around the secondary mirror. That would draw the mask closer to the corrector plate.
On a refractor, I suppose, you would not want to take this approach since you could directly easily accidentally contact the glass!
I measured the inside of the OTA. The diameter is 226.5 millimetres.
I had wondered if it would make a difference where the mask was, in front of the objective. But I'm seeing that some designs (including those by Spike-a) have a donut hole in the middle so the mask can fit around the secondary mirror. That would draw the mask closer to the corrector plate.
On a refractor, I suppose, you would not want to take this approach since you could directly easily accidentally contact the glass!
I measured the inside of the OTA. The diameter is 226.5 millimetres.
meteor spotted (Toronto)
Just saw a swift bright meteor heading south-east-south. I picked it up about 30 to 40 degrees up and it was falling straight down. It was about the same brightness as Procyon (which is mag 0.4).
Sunday, February 13, 2011
the mask
It is done. Well, the slots are done.
A bit of sanding is needed...
Need to attach a button or knob.
And trim the outer edge. I'm entertaining the idea of cutting the rim down so that the Bahtinov mask would fit inside the C8 tube vs. hanging or draping over the end of the OTA...
A bit of sanding is needed...
Need to attach a button or knob.
And trim the outer edge. I'm entertaining the idea of cutting the rim down so that the Bahtinov mask would fit inside the C8 tube vs. hanging or draping over the end of the OTA...
cutting begins
Yesterday, I glued the Bahtinov focus-mask print-out to the heavy 2 mm cardboard sheet and put it under a stack of books to press and dry.
After I fetched the new utility knife from the garage and snapped off a segment of old blade, I started cutting.
This is gonna take a while...
After I fetched the new utility knife from the garage and snapped off a segment of old blade, I started cutting.
This is gonna take a while...
Saturday, February 12, 2011
more errors spotted
I caught a couple more errors in the RASC 2011 Observer's Handbook. Submitted a note to Mr. Kelly. He just acknowledged them.
Actually, the first one was regarding the update on the website! The correction noted on page 156 should be applied to page 154.
The correction for page 223 doesn't seem to make sense. It seemed to be pointing to the wrong page as well. Patrick confirmed that it should be page 233.
Now to the handbook...
Page 300, in the Table of Coloured Double Stars, the row for 2 CVn, shows the A star as "Gb." I believed this should be "Gd" for gold colour (like the 24 Com a couple rows below).
Page 301, same Table, a minor layout issue for the next edition (and does not merit an entry on the web), eta Cas star has the VT designation in the Beauty column vs. the Diff. column.
Actually, the first one was regarding the update on the website! The correction noted on page 156 should be applied to page 154.
The correction for page 223 doesn't seem to make sense. It seemed to be pointing to the wrong page as well. Patrick confirmed that it should be page 233.
Now to the handbook...
Page 300, in the Table of Coloured Double Stars, the row for 2 CVn, shows the A star as "Gb." I believed this should be "Gd" for gold colour (like the 24 Com a couple rows below).
Page 301, same Table, a minor layout issue for the next edition (and does not merit an entry on the web), eta Cas star has the VT designation in the Beauty column vs. the Diff. column.
gallery launched
I thought it might be interesting to produce a little gallery page over on my companion site, with my life lists. The thumbnail images link to the original articles. I like how, at a glance, I can review all the interesting astroimages I have made, from film days, through a low resolution digital camera, to using sensitive cameras and remote telescopes.
Thursday, February 10, 2011
storm spotted! (Mount Teide)
I can see the storm on Saturn! Woo hoo!
Photo by SLOOH CI T2 at 11 Feb 2011 - 03:58 UTC. Seeing is a bit better. Can just make out the Cassini Division too.
Photo by SLOOH CI T2 at 11 Feb 2011 - 03:58 UTC. Seeing is a bit better. Can just make out the Cassini Division too.
first SLOOH shots (Mount Teide)
While waiting for my Saturn mission, I snapped a few of various objects. All from Canary Islands, Telescope 2.
Running Man Nebula aka NGC 1977 in Orion with 42 and 45 Orionis stars in the middle. 11 Feb 11 - 00:34:13 UTC. We're seeing down to mag 15.2 and 15.4 stars. The field is about 1° wide. It is interesting to note the view is not rotated or inverted...
[Wikipedia link: NGC 1977.]
Caldwell 7 close-up aka NGC 2403 in Camelopardalis. 11 Feb 11 - 00:36:55 UTC. We're seeing mag 16 and 17 stars. Wow. Even down to 18. Do you see NGC 2404 inside the spiral?! The blob to the left of the core. That's kinda cool.
[Wikipedia link: NGC 2403.]
Caldwell 7 wide-field. 11 Feb 11 - 00:37:08 UTC.
Then on my 02:00 UTC Saturn job, I waited for the imaging bar to reach 100% and I clicked.
Not a bad shot. Equatorial region stands out. Interesting colour. Exposure is too low for any moons. I don't see anything going on in the northern region...
[Wikipedia link: Saturn.]
§
Mt Teide, Tenerife, Canary Islands, Spain. Altitude: 2,359m. Dome 2 houses a 0.35 meter f/11 Schmidt-Cassegrain (in other words, a C14). It has a field of view of 13.1 × 8.8 arc-minutes. The camera resolution is 2,184 × 1,472 pixels.
Running Man Nebula aka NGC 1977 in Orion with 42 and 45 Orionis stars in the middle. 11 Feb 11 - 00:34:13 UTC. We're seeing down to mag 15.2 and 15.4 stars. The field is about 1° wide. It is interesting to note the view is not rotated or inverted...
[Wikipedia link: NGC 1977.]
Caldwell 7 close-up aka NGC 2403 in Camelopardalis. 11 Feb 11 - 00:36:55 UTC. We're seeing mag 16 and 17 stars. Wow. Even down to 18. Do you see NGC 2404 inside the spiral?! The blob to the left of the core. That's kinda cool.
[Wikipedia link: NGC 2403.]
Caldwell 7 wide-field. 11 Feb 11 - 00:37:08 UTC.
Then on my 02:00 UTC Saturn job, I waited for the imaging bar to reach 100% and I clicked.
Not a bad shot. Equatorial region stands out. Interesting colour. Exposure is too low for any moons. I don't see anything going on in the northern region...
[Wikipedia link: Saturn.]
§
Mt Teide, Tenerife, Canary Islands, Spain. Altitude: 2,359m. Dome 2 houses a 0.35 meter f/11 Schmidt-Cassegrain (in other words, a C14). It has a field of view of 13.1 × 8.8 arc-minutes. The camera resolution is 2,184 × 1,472 pixels.
SLOOH snaps
I found the SLOOH Canary Islands telescopes running tonight. Jumped on a couple of automated missions and snapped some photos.
Wednesday, February 09, 2011
announced Stellarium course
Ralph pitched my introductory Stellarium course during the meeting announcements. I'll send a notice to the Yahoo!Group. We'll see if anyone is interested.
two months too long
Tried to help one of our Toronto Centre members renew. She had let her RASC membership lapse for two months, I think. Just over two months. And the online system would not respond. It advised her to phone the office. She was not happy about that.
I wonder if they'll apply her new/renewal retroactively...
I wonder if they'll apply her new/renewal retroactively...
ironic
After loading a couple of the SLOOH cards into my profile, I started browsing around. What were the 4 telescopes aiming for. I even made a reservation for Saturn. And wouldn't you know it... It's rainy and humid in the Canary Islands, it's overcast in Chile, and the sun's up in Australia.
Meanwhile, it's perfectly clear in Toronto! Pah!
Meanwhile, it's perfectly clear in Toronto! Pah!
Moon and Hamal (Toronto)
It was clear and cold when Jason and I stepped out of Mackenzies. He, already shivering, headed 2 blocks east; I walked west down the gully and up the hill, thinking the Moon unusual, and noting Hamal above and to the right.
See?! Should have prepared my telescope a couple of nights back...
See?! Should have prepared my telescope a couple of nights back...
survey prep
Met up with Jason tonight. Chatted about the strategy event. Moved the member web site survey forward. Continued our web site redesign planning.
on SLOOH
Created my SLOOH account tonight, the free tier. Later I'll upgrade and load some of the cards I have at home. (The huge stack that I have...) Then, see if I can get some shots of cool objects. It'll be fun to use on cloudy nights...
Tuesday, February 08, 2011
roll out the green carpet
Malcolm had a green rug from his rec room that he offered to me some time ago. To replace the smallish rug I've been using under the telescope when outdoors. He hauled it out of his garage tonight and stuff it in his car. In turn, I jammed it in my garage beside the fender of my car. I'll roll it out in the spring to see how big it is and cut it down as needed.
A rug under the 'scope great when one has dropsy.
A rug under the 'scope great when one has dropsy.
two shovels
I bought two new snow shovels for the CAO.
We'll schlep them up to the observatory in a couple of weekends.
We'll schlep them up to the observatory in a couple of weekends.
tiny 393s
Picked up a couple 393 batteries for the digital pen. InfiniCell 2300103A (aka SR48W) from The Store Formerly Known As Radio Shack. Silver oxide, 1.5 volts.Also activated that crazy 3-year replacement plan thing.
I made a little plastic tab to put between the batteries to open the circuit on the pen. Prevent drain when I'm not sketching or logging on paper.
Disclaimer: May not appear as shown.
wing nut
At last, I found stupid wingnuts for my stupid triangular tray for the Vixen wood tripod.
It was a dozen years ago when I lost one of the three wing nuts. Probably at a campground or in a field somewhere, in the dark, it went down in the grass. Now, it's a lump of rust. Incredibly, at the time, in my miscellaneous nuts and bolts jar I found a match. Well, close match. The threads worked while it was a bit different in size and cosmetics. It worked. That's what mattered.
It was a couple of years ago (probably more) that I lost the second wing nut. This time, all the wing nuts I tried from my collection of spares, none fit. I suspected the tripod was metric and my extras were Imperial. But I did find a regular hex nut that worked. Not convenient to use but I found if I attached it first I could turn the entire tray into it to tighten.
Today, while cutting some extra keys at Home De Pot, I found 10-32 wing nuts! Woo hoo!
I know, I know... small things...
It was a dozen years ago when I lost one of the three wing nuts. Probably at a campground or in a field somewhere, in the dark, it went down in the grass. Now, it's a lump of rust. Incredibly, at the time, in my miscellaneous nuts and bolts jar I found a match. Well, close match. The threads worked while it was a bit different in size and cosmetics. It worked. That's what mattered.
It was a couple of years ago (probably more) that I lost the second wing nut. This time, all the wing nuts I tried from my collection of spares, none fit. I suspected the tripod was metric and my extras were Imperial. But I did find a regular hex nut that worked. Not convenient to use but I found if I attached it first I could turn the entire tray into it to tighten.
Today, while cutting some extra keys at Home De Pot, I found 10-32 wing nuts! Woo hoo!
I know, I know... small things...
don't piss off Mama Bear
Was chatting with Grace about the CAO, stickers, and strategic planning. It's good to have her in my corner!
Grace found the stickers
I had asked Grace to take a look around her dining room hutch and the computer table for the revised circuit breaker panel sticker sheets I had made up and given to Tony.Tony thought they were already at the CAO. I had looked in all the obvious spots without finding them. I didn't want to print them again, wasting the paper.
She found them! Yeh!
returned RS-485
I was a little distracted and anxious, having just misplaced my palmtop. Probably looked like a fidgety con artist standing there at the counter. But Sayal accepted the return of the RS-485 converter when I said it didn't work and fully refunded my money. Whew. Like!
makes me happy
The new SkyNews magazine was poking out of my mailbox this morning. It always makes me happy.Mar/Apr 2011 issue. The cover article is about how backyard astronomers are producing images that rival the pros. I wonder who I will know... Oh. And a little article on Leslie Neilsen and Forbidden Planet.
Today, I was especially pleased to see my correct address. So, even though the RASC National Office never returned my messages, I knew my new address was in the hands of the SkyNews distribution wranglers.
Monday, February 07, 2011
no good deed
Steve downloaded and installed my Turn Left At Orion observing lists for SkyTools. He said, "Looks good."
Then he pointed out that I seemed to have triggered a little flame war on the SkyTools Yahoo!Group. Wow.
starhopper44 said "most of us are advanced" and have "more complex setups" and wouldn't use something like this. That got under the skin of a few.
Jim and Fred, Yahoo! members, pointed out that they have small 'scopes and are not using GOTO. Fred went on to say, "I appreciate lists like this."
Terry said to me that here was a good example of "no good deed goes unpunished."
Even Greg was shaking his head.
Then he pointed out that I seemed to have triggered a little flame war on the SkyTools Yahoo!Group. Wow.
starhopper44 said "most of us are advanced" and have "more complex setups" and wouldn't use something like this. That got under the skin of a few.
Jim and Fred, Yahoo! members, pointed out that they have small 'scopes and are not using GOTO. Fred went on to say, "I appreciate lists like this."
Terry said to me that here was a good example of "no good deed goes unpunished."
Even Greg was shaking his head.
warm 'em
I guess I haven't observed in the winter or extremely cold situations for a while. So I'm a little frosty...
Sorry. Sorry about that. It was right there! Come on. I couldn't not take it...
Rusty. I was rusty.
I couldn't remember whether I should warm eyepieces or keep them at ambient temperature. But I did experience minor hazing issues when I was keeping them outside, under a towel still, but at cool temps. As I would look through the eyepiece for a long time, I'd see a halo appear around bright objects. It was dew or frost from my body. My eyeball was heating the glass! I also had to be careful not to breathe on the ocular.
But after some net stumbling, of course, I realised / remembered / recalled / undersood that you have to heat the eyepieces. As you do in the summer, you do in the winter. Duh!
So, I should have kept the eyepieces in the warm room of the GBO.
I asked Dietmar if we had an eyepiece heater and was not surprised by his answer. A little disappointed though. So, in the meantime, it will be the low-bandwidth, simple solutions required: keep eyepieces in pockets. A little more challenging when you have 5 layers on.
Then there's the issue of the Tele Vue refractor. Without an objective heater, the telescope might not be usable... I'll need to look into that.
Or, one could just persevere as did wimmer, as he noted in his ASOD entry.
That's a photo by wimmer of his Celestron 5" SCT on SLT mount. He said the temperature was around -20°C. Incredible.
And that's the photo I snapped of the objective cover for the C14.
Sorry. Sorry about that. It was right there! Come on. I couldn't not take it...
Rusty. I was rusty.
I couldn't remember whether I should warm eyepieces or keep them at ambient temperature. But I did experience minor hazing issues when I was keeping them outside, under a towel still, but at cool temps. As I would look through the eyepiece for a long time, I'd see a halo appear around bright objects. It was dew or frost from my body. My eyeball was heating the glass! I also had to be careful not to breathe on the ocular.
But after some net stumbling, of course, I realised / remembered / recalled / undersood that you have to heat the eyepieces. As you do in the summer, you do in the winter. Duh!
So, I should have kept the eyepieces in the warm room of the GBO.
I asked Dietmar if we had an eyepiece heater and was not surprised by his answer. A little disappointed though. So, in the meantime, it will be the low-bandwidth, simple solutions required: keep eyepieces in pockets. A little more challenging when you have 5 layers on.
Then there's the issue of the Tele Vue refractor. Without an objective heater, the telescope might not be usable... I'll need to look into that.
Or, one could just persevere as did wimmer, as he noted in his ASOD entry.
That's a photo by wimmer of his Celestron 5" SCT on SLT mount. He said the temperature was around -20°C. Incredible.
And that's the photo I snapped of the objective cover for the C14.
flashlight, no headlight, done
It's finally done...
I got hung up on this convoluted project. Stalled, for months. It was the mounting to the head that I couldn't figure out for the longest time.
The project started out simply enough, to build a flashlight patterned off the Rigel design, with the LEDs emitting from the end. Power efficient so to last long and designed around standard batteries so to stop burning through lithium coins. With LEDs of a colour I could explicitly choose.
The pre-planning, the circuit prototyping, sourcing parts, the schematic work, the circuit design, laying out, soldering, all went swimmingly. The deep red LEDs worked great. I found a 9.5 x 6.0 x 2.5 cm project box that would fit the circuitry and carry a 9 volt transistor style battery. Good size and form factor for a hand held unit.
Things turned or shifted when my hacked red LED clip light broke and that I wanted a replacement. Not just another baseball clip light (converted to red). Not a new head lamp with a red LED (like the MEC I had given Mom; even though her uses AAAs). Perhaps my custom flashlight idea could be used. But it would have to be wearable, to keep hands free, of course. But therein lay the trap.
I started going down this path of trying to build a light that would mount in an equivalent way, clip to the bill of a cap, or perhaps mount like my old MEC head lamp with stretchy bands around the side and top of the head. I tried to figure out a way to get the bulky plastic box to sit atop the bill of a cap or rest against my forehead. I actually found a curved piece of plastic that I considered as a forehead contact point. But then the whole layout of the project box was off with the LEDs in the end. I muddled over my old MEC head lamp, trying to figure out if I could fit the project box to the mount. Given the age of the MEC light, new straps were needed. That presented a new stumbling block of where to find wide elastic straps. I just did not like where things were going. Onto the back burner again.
I think it was as I was searching for little red LED dongle light things [ed: new link] that could be attached to a coat lapel or zipper when I stumbled across the Nite Ize company and their flashlight holding headband. Brilliant idea. Looks like a great product. I think I even found that Bass Pro carried it. So I made a note to check it out.
But that started the wheels turning. If I could make my own headband, perhaps I could affix another strap, perpendicular to the headband, and tie around the project box. And that meant I wouldn't have to reconfigure the circuitry and LEDs. Looked like I was going to be firing up the sewing machine soon.
I think that's what caught my eye about the Velcro Velstretch bands I found at the hardware store. They were the right length for a headband. Better still, they were stretchy (while the Nite Ize product webbing is not elastic). I felt that something that could be at some slight tension would be better. The other interesting tidbit about the Velstretch bands is that entire exterior of the band is loop material. This allows for infinite adjustment. And that would later give me another idea...
Today, not sure why, cloudy skies perhaps, needing a distraction, I decided to finish the project box assembly.
With the new hacksaw, I cut the circuit board to fit the internal guides in the project box. A bit of sanding made for a perfect fit.
I stared at a couple of small switches I had selected for possible use as the main on/off control. The round switch with red toggle was attractive but way too big. It looked like the tiny black toggle would be the way to go. But as I checked fitment, I rejected it as well. Still too large. I looked in the parts bin but didn't find any smaller switches. Whoa. Hold on. Back up.
I picked up a small circuit board salvaged from an old CLA car power adapter. It had a voltage selector switch. It was very small but with robust legs. Ha! I could mount this right to the circuit board, accessible in the same direction or orientation as the rheostat brightness control. Much better. I desoldered the black switch for the CLA board. I routed the power switch leads to the edge of my circuit board and made the "new" switch leapfrog them. It was perfect.
I took the side of a clear plastic box and made a lens. I cut some holes for the power switch and brightness wheel. Bit of trimming was necessary to get everything to line up and avoid collisions.
From another project I grabbed a rubber grommet, slotted it, and fit it at the rear of the PCB to prevent the board from moving backwards as the switch and dial are used.
Cut the deep red LED leads to allow the 5mm domes to sit behind the clear lens.
Cut back the circuit board power lines, soldered the 9v leads, and heated the shrink wraps. Looped the power cords around one of the project box screw posts as an anchor and snapped everything together. Installed the two long screws.
And so after many months, the deep red LED flashlight, inspired by the Rigel, was finally done. Installed a fresh 9v battery and took it for a test drive in the dark bedroom. It was fantastic. Lots of light, dimmable, great colour.
Now, the final step was to see if it could replace the damaged clip light.
While in the bedroom, I hauled astronomy box γ down from the shelf and removed the Ziploc bag with Velcro hook and loop pieces. I found a self-adhesive 5cm square piece of hook already cut. Perfect. I attached it to the "back" of the project, same side as the battery compartment.
At last, I put the Velstretch band around my head. Set the tension so snug, but not too tight. Turned on the deep red light. Aimed it at a piece of paper in front of me. Then slapped the flashlight it to the head band. Amazing.
Added a eyehook to which I attached a lanyard. Now it can be worn around one's neck too. And when in head band mode, wearing the lanyard means it is tethered, which should avoid it bouncing off the ground...
Without specifically intending it, I suddenly realised I had created a far superior solution. The flashlight can be used normally, that is as a hand held unit. When used with the head band, it is infinitely adjustable. Unlikely the Nite Ize band, I can tilt or pitch the flash light, allowing me to keep my head and neck at a comfortable angle. Can be worn directly or over any hat.
I'm so happy with the finished result!
I got hung up on this convoluted project. Stalled, for months. It was the mounting to the head that I couldn't figure out for the longest time.
The project started out simply enough, to build a flashlight patterned off the Rigel design, with the LEDs emitting from the end. Power efficient so to last long and designed around standard batteries so to stop burning through lithium coins. With LEDs of a colour I could explicitly choose.
The pre-planning, the circuit prototyping, sourcing parts, the schematic work, the circuit design, laying out, soldering, all went swimmingly. The deep red LEDs worked great. I found a 9.5 x 6.0 x 2.5 cm project box that would fit the circuitry and carry a 9 volt transistor style battery. Good size and form factor for a hand held unit.
Things turned or shifted when my hacked red LED clip light broke and that I wanted a replacement. Not just another baseball clip light (converted to red). Not a new head lamp with a red LED (like the MEC I had given Mom; even though her uses AAAs). Perhaps my custom flashlight idea could be used. But it would have to be wearable, to keep hands free, of course. But therein lay the trap.
I started going down this path of trying to build a light that would mount in an equivalent way, clip to the bill of a cap, or perhaps mount like my old MEC head lamp with stretchy bands around the side and top of the head. I tried to figure out a way to get the bulky plastic box to sit atop the bill of a cap or rest against my forehead. I actually found a curved piece of plastic that I considered as a forehead contact point. But then the whole layout of the project box was off with the LEDs in the end. I muddled over my old MEC head lamp, trying to figure out if I could fit the project box to the mount. Given the age of the MEC light, new straps were needed. That presented a new stumbling block of where to find wide elastic straps. I just did not like where things were going. Onto the back burner again.
I think it was as I was searching for little red LED dongle light things [ed: new link] that could be attached to a coat lapel or zipper when I stumbled across the Nite Ize company and their flashlight holding headband. Brilliant idea. Looks like a great product. I think I even found that Bass Pro carried it. So I made a note to check it out.
But that started the wheels turning. If I could make my own headband, perhaps I could affix another strap, perpendicular to the headband, and tie around the project box. And that meant I wouldn't have to reconfigure the circuitry and LEDs. Looked like I was going to be firing up the sewing machine soon.
I think that's what caught my eye about the Velcro Velstretch bands I found at the hardware store. They were the right length for a headband. Better still, they were stretchy (while the Nite Ize product webbing is not elastic). I felt that something that could be at some slight tension would be better. The other interesting tidbit about the Velstretch bands is that entire exterior of the band is loop material. This allows for infinite adjustment. And that would later give me another idea...
Today, not sure why, cloudy skies perhaps, needing a distraction, I decided to finish the project box assembly.
With the new hacksaw, I cut the circuit board to fit the internal guides in the project box. A bit of sanding made for a perfect fit.
I stared at a couple of small switches I had selected for possible use as the main on/off control. The round switch with red toggle was attractive but way too big. It looked like the tiny black toggle would be the way to go. But as I checked fitment, I rejected it as well. Still too large. I looked in the parts bin but didn't find any smaller switches. Whoa. Hold on. Back up.
I picked up a small circuit board salvaged from an old CLA car power adapter. It had a voltage selector switch. It was very small but with robust legs. Ha! I could mount this right to the circuit board, accessible in the same direction or orientation as the rheostat brightness control. Much better. I desoldered the black switch for the CLA board. I routed the power switch leads to the edge of my circuit board and made the "new" switch leapfrog them. It was perfect.
I took the side of a clear plastic box and made a lens. I cut some holes for the power switch and brightness wheel. Bit of trimming was necessary to get everything to line up and avoid collisions.
From another project I grabbed a rubber grommet, slotted it, and fit it at the rear of the PCB to prevent the board from moving backwards as the switch and dial are used.
Cut the deep red LED leads to allow the 5mm domes to sit behind the clear lens.
Cut back the circuit board power lines, soldered the 9v leads, and heated the shrink wraps. Looped the power cords around one of the project box screw posts as an anchor and snapped everything together. Installed the two long screws.
And so after many months, the deep red LED flashlight, inspired by the Rigel, was finally done. Installed a fresh 9v battery and took it for a test drive in the dark bedroom. It was fantastic. Lots of light, dimmable, great colour.
Now, the final step was to see if it could replace the damaged clip light.
While in the bedroom, I hauled astronomy box γ down from the shelf and removed the Ziploc bag with Velcro hook and loop pieces. I found a self-adhesive 5cm square piece of hook already cut. Perfect. I attached it to the "back" of the project, same side as the battery compartment.
At last, I put the Velstretch band around my head. Set the tension so snug, but not too tight. Turned on the deep red light. Aimed it at a piece of paper in front of me. Then slapped the flashlight it to the head band. Amazing.
Added a eyehook to which I attached a lanyard. Now it can be worn around one's neck too. And when in head band mode, wearing the lanyard means it is tethered, which should avoid it bouncing off the ground...
Without specifically intending it, I suddenly realised I had created a far superior solution. The flashlight can be used normally, that is as a hand held unit. When used with the head band, it is infinitely adjustable. Unlikely the Nite Ize band, I can tilt or pitch the flash light, allowing me to keep my head and neck at a comfortable angle. Can be worn directly or over any hat.
I'm so happy with the finished result!
digital pen dead
Tried to use my Dane-Elec digital pen a little while ago but the receiver did not acknowledge any pen activity. I suspected the 2 little on-board batteries were dead. Used it a lot in Jan and Feb last year...Did volt tests:
battery one: 0.60
battery two: 0.22
Should be 1.5 VDC. So, need to find some new tiny GP393 cells.
finish RASC TC calendar
I finally applied all the remaining events into the mini-calendar on the RASC Toronto Centre web site, viewed from the home page.
ordered green cable
From Zengineering, I ordered a 25 foot "green" cable (with RS-485 conversion built in) for the MallinCam Hyper Color. I was tired of fiddling with the RS-232 to RS-485 converter which wasn't working. In the end, the custom cable comes in cheaper, even with shipping from US.Now I just need to return the converter without incurring a nasty 30% restocking fee.
Windows vs. Macintosh
As I prepared course materials for Stellarium 0.10.6 training, I captured the shortcuts required on an Apple MacBook. Now, for your reference, a Windows or Macintosh keyboard shortcut guide. Thanks to Sharmin!
* Recently new or changed shortcuts are marked with an asterisk.
† Keyboard shortcuts noted with a dagger are associated with a plug-in. They may not function if the plug-in is not active.
Most quick reference listings (including the one inside Stellarium's help) are improperly designed. They show the key first then the action, forcing you to think about a key combination, even if you're not interested in it. You'll see I've done the opposite!
Finally, when using Stellarium on the Apple Macintosh computer, the keyboard shortcuts shown in the help window and toolbar tip pop-ups are incorrect. For example, there are references to using the Ctrl key. This references to Windows. In general, on a Mac, substitute the Command key for the Ctrl...
| controlling the surroundings |  |  | ||
| show Location window | F6 | Fn F6 | ||
| toggle cardinal compass points | —— | q | — | q |
| toggle compass marks †* | Ctrl c | ⌘ c | ||
| toggle ground and buildings | g | g | ||
| toggle ground fog | f | f | ||
| toggle atmosphere or air | a | a | ||
| controlling sky appearance | | | ||
| toggle stars | s | s | ||
| toggle constellation lines | c | c | ||
| toggle constellation boundaries | b | b | ||
| toggle constellation labels | v | v | ||
| toggle constellation artwork | r | r | ||
| toggle planet labels and circles | p | p | ||
| toggle planet orbits | o | o | ||
| toggle planet trails | Shift t | Shift t | ||
| toggle nebula labels and circles | n | n | ||
| show Sky and Viewing Options | F4 | Fn F4 | ||
| controlling gridlines | | | ||
| toggle alt/az grid lines | z | z | ||
| toggle equatorial grid | e | e | ||
| toggle ecliptic line | , (comma) | , | ||
| toggle celestial equator | . (period) | . | ||
| toggle meridian line | ; | ; | ||
| changing image presentation | | | ||
| toggle horizontal flipping | Ctrl Shift h | ⌘ Shift h | ||
| toggle vertical flipping | Ctrl Shift v | ⌘ Shift v | ||
| controlling "regular" time | | | ||
| show date/time window | F5 | Fn F5 | ||
| set date/time to now | 8 | 8 | ||
| set time rate to zero | 7 | 7 | ||
| increment forward time speed | l (lower case L) | l | ||
| increment reverse time speed | j | j | ||
| run time at normal speed | k | k | ||
| decrease time speed a little | Shift j | Shift j | ||
| increase time speed a little | Shift k | Shift k | ||
| jump forward 1 hour | Ctrl = (equal) | ⌘ = | ||
| jump backward 1 hour | Ctrl - (hyphen) | ⌘ - | ||
| jump forward 1 day | = (equal) | = | ||
| jump backward 1 day | - (hyphen) | - | ||
| jump forward 1 week | ] | ] | ||
| jump backward 1 week | [ | [ | ||
| controlling sidereal time | | | ||
| forward 1 sidereal day | Alt = (equal) | Option = | ||
| backward 1 sidereal day | Alt - (hyphen) | Option - | ||
| forward 1 sidereal week | Alt ] | Option ] | ||
| backward 1 sidereal week | Alt [ | Option [ | ||
| zooming | | | ||
| quickly zoom in/out | mouse wheel | mouse wheel | ||
| zoom in | PgUp or Ctrl Up Arrow | Fn Up Arrow | ||
| zoom out | PgDn or Ctrl Dn Arrow | Fn Down Arrow | ||
| zoom close to selected object | / (slash) | / | ||
| zoom out fully | \ (backslash) | \ | ||
| panning | | | ||
| quickly pan celestial sphere | left-drag | drag | ||
| pan right | Right Arrow | Right Arrow | ||
| pan left | Left Arrow | Left Arrow | ||
| pan up | Up Arrow | Up Arrow | ||
| pan down | Dn Arrow | Down Arrow | ||
| toggle EQ or alt/az mount | Ctrl m | ⌘ m | ||
| working with objects | | | ||
| select an object visually | left-click | click | ||
| centre on selected object | spacebar | spacebar | ||
| toggle tracking of object | t | t | ||
| deselect object | right-click | ⌘-click | ||
| display search dialog box | Ctrl f or F3 | ⌘ f or Fn F3 | ||
| travel, i.e. go to a planet | Ctrl g | ⌘ g | ||
| toggle angular measurement †* | Ctrl a | ⌘ a | ||
| working with satellites † | | | ||
| configure artificial satellites * | Alt z | Option z | ||
| toggle satellite display * | Ctrl z | ⌘ z | ||
| toggle satellite labels * | Shift z | Shift z | ||
| controlling the application | | | ||
| show configuration window | F2 | Fn F2 | ||
| show help/about window | F1 | Fn F1 | ||
| show script console window | F12 | (untested) | ||
| toggle fullscreen/window | F11 | (none) | ||
| toggle GUI toolbars/menus | Ctrl t | ⌘ t | ||
| save screenshot to desktop | Ctrl s | ⌘ s | ||
| close a window * | Esc | Esc | ||
| quit from Stellarium | Ctrl q | ⌘ q |
* Recently new or changed shortcuts are marked with an asterisk.
† Keyboard shortcuts noted with a dagger are associated with a plug-in. They may not function if the plug-in is not active.
Most quick reference listings (including the one inside Stellarium's help) are improperly designed. They show the key first then the action, forcing you to think about a key combination, even if you're not interested in it. You'll see I've done the opposite!
Finally, when using Stellarium on the Apple Macintosh computer, the keyboard shortcuts shown in the help window and toolbar tip pop-ups are incorrect. For example, there are references to using the Ctrl key. This references to Windows. In general, on a Mac, substitute the Command key for the Ctrl...
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