Wednesday, February 27, 2019

red band, white disk (Bradford)

Saw an evocative orange-red stripe to the east, at least from high ground. Couldn't see it as I neared the train station. A "sailor's warning..."

Noted a very soft crescent glowing in the south.

Snow is coming...

Tuesday, February 26, 2019

tomorrow's meeting cancelled

I just learned that tomorrow's Recreational Astronomy Meeting for the RASC Toronto Centre is cancelled.

cancelled meeting note from RASC Toronto web site

This is because of the impending heavy snow.

Saturday, February 23, 2019

about curved notched plastic

I wanted to build a custom dew heater strap. Well, I've wanted to do that for a long time...

In 2006, I started collecting (harvesting?) large quantities of nichrome wire. I even built a dual-element accessory for my finder scope. But I shelved that after a couple of runs.

With the recent failure of the Kendrick 2-inch eyepiece strap, these thoughts were rekindled.

I found inspiration in Eteny's DIY dew heater DIY project page where he made simple heating elements by wrapping nichrome wire around a plastic sheet.

I liked his approach with the plastic core but I was worried about how flexible that might be. Would it coil around a small eyepiece? Sure, it depended on the thickness of the material. And then, it hit me. Start with curved plastic! As Rhonda and I discussed the matter, she handed me a pale blue transparent plastic bottle, one that held her favourite bubbly water. Look at that!

Again, I liked his approach with the wire wrapped around the plastic core as I saw that very little or no stress would be transferred to the wire element itself as the strap was opened or wound around something. Clever. But I didn't like how the wires could wander, possibly shorting. He taped down the wire but I wanted a better solution. In a moment of clarity, I saw that if notches were made along the side of the plastic strip, the wire could be held in place, and with a bit of tension, unable to wander.

heating element design in zigzag pattern

I made a scaled diagram in Visio considering regular notches in the plastic strip and then I counted the vertical and angled runs. Total length about 85 centimetres.

Later, I measured the bottle diameter and tallied everything in an Excel sheet. Given the physical length of wire, I would just need to find an appropriate resistance from the nichrome supply.

This was exciting!

Tuesday, February 19, 2019

checked hot wires

Checked my nichrome wire supply. Direct purchase, from toasters, from hairs dryers. In preparation of making a dew heater...

Monday, February 18, 2019

monthly doubles for Feb 2019

Issued my double star "bulletin" for February 2019. It is a short list of suggested targets. I shared this on the RASC Toronto Centre forums. And I post here for all.


Hi there, hi.

If it isn’t cloudy and grey, it is bitterly cloud, it seems. Such that it is, here are some double and multi-star targets for your consideration for February.

staralso known asalternate catalogue 
φ (phi) AurBUP 79SAO 58051
11-12 Cam-SAO 25001
HR 2879 GemSTF (Struve) 1108SAO 79489
ζ (zeta) GemMekbuda or SHJ 77SAO 79031
HD 34071 LepGAL 378SAO 150258

Remember double stars work in the city as well as in dark skies. I look forward to hearing how you did! Any questions?

Blake Nancarrow
astronomy at computer-ease dot com

tested LED dimmer again

Tried LED dimmer again, with my little custom Telrad heater with resistors. Heat came out! Whiskey tango foxtrot, I thought this thing didn't work?! Carefully measured the amperage with the (repaired) Micronta multi-meter: 0.11A. Huh.


Tried the other heat sources...

Big heating pad: 1.6A.
Kendrick 8" heating strap: 1.0A.
Hacked Heatech cup warmer: 700 mA.

Look at that.


Tested the Kendrick 2" strap with the Micronta audible continuity resistance setting... and was able to get a tone when I bent the strap a particularly way. It has a broken wire!


I don't know what happened... I don't remember now. But it seems that in late-January I was doing lots of little tests and checks and I had a malfunctioning multi-meter as well as an erratic dew strap. Looking back, the cheapo LED dimmer had worked fine.

My theory is that the dew strap itself was not working (hadn't been since early January) and it didn't draw any power from the dimmer circuit so I assumed the LED dimmer was bad.


I need to make some good dew straps. I have lots of nichrome wire...

Sunday, February 17, 2019

finished dew controller

Buttoned up the dew heater controller. It works well. Now I can battle sultry nights on two independent rigs.

Cut the lead wires from the components off the bottom of the finished printed circuit board. Cut the test power feed. Used thermal paste between the sinks and the big transistors. Finally drilled the PCB for the large wire of the reverse polarity Schottky diode and connected the positive power input line.

Tried some plastic standoffs with tiny screws with hot glue but I wasn't really happy. Hacked some shrink wrap tube cut very short and used contact cement.

Wired up the fused Cigarette Lighter Adapter with heavy wire, cut a bit longer than my Kendrick controller.

Attached the case parts. Stoopid skating drill bits; should have used a press. Installed the Richlok plastic strain relief. Soldered the big pots and the indicator LEDs. Pressed the LEDs into place; locked. Soldered the shell tabs of the RCA female connectors in advance. Tightened the RCA jacks with a 9mm spanner. Once the PCB was glued in place, I soldered the RCA plugs on their centre pins.

Glued the power switch into the case. I wanted to use removable connectors to the tabs but they were too deep so I (carefully) hard-wired the SPST.

Summit Brand. Sony guts.

Heated the shrink tube on the power feed. Closed up the box. All done. Tested. Works good.

Project box sealed. Go to eleven.

In a moment of inspiration, printed up some labels.

Shared the photo with Charles on Facebook. He quickly responded: "When we're observing and it's hit the dew point and our dew controller is already on ten and we need a bit more to get us over the edge we can go to eleven." Couldn't have said it better.

None more black.

Friday, February 15, 2019

gazing from 9700 metres (Lachute)

As we rose above the clouds, I noted the Moon, getting bright, high up. Couldn't view it straight on until the plane banked right.

Saw Sirius. Bright, blue-white, intense.

Then I saw deep orange Betelgeuse, and when I squinted, without my eyeglasses on, all of Orion.

Very dark sky above the pale blue clouds below.

Sunday, February 10, 2019

received more NGC 4388 data

I imaged NGC 4388 about a year ago with BGO. The result was fair but I wondered if I could improve on it. So I put it in the queue again. Not sure of the latest photon collection is any better. I also noticed the frame sizing was different, wider.

Still on the Apogee camera, according to the FITS header... Was it cleaned? The axis values show as 1536 pixels.

Saturday, February 09, 2019

received SkyNews Mar/Apr

cover of the Mar/Apr SkyNews magazine
w00t! Received the latest SkyNews magazine today. Excited to read this one with the cover emblazoned with Fight the Light! Content on light pollution! We must fight the light!

Inside, after a quick skim, I noted lots of wonderful photography including shots with the Pleaides and comets.

I also look forward to reading the piece on astroimaging inside city limits. I need all the help I can get.

Friday, February 08, 2019

built a working board

It took me a while to resolve the dew heater controller circuit problems but it is done now. Circuit works.

I sorted an issue with the switching transistors. Initially, I mistakenly used the same pin position assignments for the 2N2222 and TIP31C pieces.

transistor representations in ExpressPCB

I learned that you need to go back to the schematic and ensure the pins of the physical part correspond to the schematic.

After testing a simple 555 schematic from Math Heijen, I successfully debugged my soldered 556 board layout. Carefully comparing the schematic and board layout, I found the error. It was caused by a fault back in mid-January, when I first considered the board layout and I changed from the stock diode object. With my "custom" diode part, I flipped the polarity. I edited the part polarity in ExpressPCB and repaired the board.

Below, is the full, correct board layout I used. Eleven versions! [ed: Oops. Forgot to update diode D7, the Schottky. Corrected version 12 shown.]

v12 printed circuit board layout for the custom dew heater

The board has left and right sections meaning the left R1 potentiometer controls the power output to heaters H1 and H2 and which is reflected in diode D5. Close examination will reveal the correct orientation of the signal diodes. It's a little messy around the TO-18 transistors but the traces drawn indicate where the long legs were attached (when possible). The offsetting (again) of B1 and F1 show the power source is outboard and the fuse is inside the CLA plug.

Cut the long 4-40 bolts for the heat sinks (first time doing that with the GB wire stripping tool). The PCB was (nearly) done and working.

photograph of the completed working PCB

The heavy gauge red and black wires (in the photo) at the upper corners of the PCB are for the heater networks of course. The yellow, purple, and black wires at the bottom corners are for the pots. In my case, the black wires are for the middle pins. You can clearly see one of the indicator diodes; the other is cropped out. The black wire going from the middle of the board straight up in the negative 12 volt power input. I used the red lead at the bottom-right as a temporary feed into the PCB.

With the controller working, I was able to test with the Schottky diode. It was fine, of course. But it will require some special effort: the pins are a bigger girth so I'll have to drill the PCB...

I'm ready for the next phase. Yeh, I can cut the long leads off the bottom of the PCB. I'll attach the case parts now, the pots, the RCA plugs, the power switch, and power feed. Saw a neat trick of gluing stand-offs to the project box so I'll see if I can pull that off...


Next: finished dew controller.

snow squall Moon (Bradford)

Spotted a crescent Moon, slowly darkening, slowly dropping, as I trudged home from the bus stop.

Wednesday, February 06, 2019

doubled down on M100 (Halifax)

I continue to double-down on Messier objects. I first viewed Messier 100 on 4 May '13. Had a quick look at faint M100 in the summer of 2018. Sent BGO to the target so to have a good long look at the face-on galaxy in Coma.

galaxy Messier 100 in luminance

Luminance only, 60 seconds subexposures, 10 stacked shots. FITS Liberator, Paint.NET. North is up; east is left.

Wow. What a beautiful spiral. Two main majestic arms radiate from the inner ring. The arms have kinks? They have rich texture with light star-filled regions. Fanning. The core is compact but bright. M100 is also known as NGC 4321.

IC 783A lies to the west-south-west, a small round bit of fluff.

Due east is the large somewhat oval fuzzy of NGC 4328.

North of 4328 is tiny PGC 40214.

NGC 4322 is north-north-east of the big spiral. A dim oval patch.

Wow. An amazing sight.


Wikipedia link: Messier 100.

revisited NGC 4216

Previously had a go at galaxy NGC 4216 on 20 May '17 and 22 Apr '18. Still not satisfied. Asked the BGO robot to try again. This result was not any better.

returned to NGC 3432

Hello! Wasn't expecting anything. But emails started rolling in from the Burke-Gaffney Observatory as it imaged Finest NGCs starting with 3432. I'm hoping to improve on the quality. Last capture was on 19 Apr '17. Unfortunately, no better... Average transparency and poor seeing. The new ECMWF forecast showed increasingly clouds.

Sunday, February 03, 2019

soldered stuff

It was Soldering Day!

Happy with the physical layout, I soldered parts to the new custom dew heater controller printed circuit board. Took a while! Did the components in the afternoon and the jumpers and leads in the evening.

Did up the Kick-Me-Not red LED blinkie tripod lights with little battery packs. Now I can use rechargeable AAA batteries.

And to the Oregon Scientific portable weather station, I hooked up an external 4xAAA battery pack. Like the OneWorld hack, no more CR2032 batteries! Previously the Oregon needed two and the OneWorld consumed one. Now I can use standard batteries. Actually, I could use rechargeables here too...

Later I shrunk the shrink-wrap on the connection points. Done!

Tested everything.

No problems with the KMN lights. After converting three pieces to use external power over 2 years ago, it was good to have these up and running again.

The Oregon beeped to life as I made the second connection. Good stuff! I don't have to feel anxious about using the backlight anymore.

But the dew heating system? My first powered test failed. It was not working correctly. Both LEDs lit but burned steady! They did not blink no matter what I did with the pots. Oh boy. What have I done...


Oops. Found that I had installed diode D3 backwards! And I was missing a wire on net N6 from capacitor C4. Fixed. Tested. It still didn't work right. Crikey.

Thank goodness for desoldering braid.

Checked for shorts, touching wires. As much as possible, I tested components on the board. The resistors all seemed OK. The pots seemed OK and the pin outs were acting as I expected. The diodes D1 through D4 seemed OK. Couldn't get reliable readings from the transistors in their circuits. Checked for continuity on all the nets: OK.

I redid the schematic from scratch but ended up with the same result. I redid the layout in ExpressPCB: again, same result. Dang...


Next: built a working board.

Saturday, February 02, 2019

3D dew controller

Exported the 123D file to X3D format so it can be displayed or rendered in 3D. It's kind of amazing what one can do at home...

happy groundhog day...

I dunno about you but if I was a marmot in Canada, I wouldn't be crawling out of my den in this weather.

an irked groundhog


imaged M90 (Halifax)

Lovely spiral galaxy Messier 90 was imaged by the BGO robot. It too is in Virgo, another M-object viewed but once, back on that big night in May 2013.

spiral galaxy Messier 90 in luminance

Luminance only, 60 seconds subexposures, 10 stacked shots. FITS Liberator, Paint.NET. North is up; east is left.

The core of M90 is compact, tiny. Love the dust lanes within the bright glow of the disc. The outer reaches of the spiral arms to the north look distorted, extended.

Little galaxy IC 3583 hovers to the north.


Wikipedia link: Messier 90.

imaged M89 (Halifax)

BGO nabbed another Messier for me. I had viewed M89 aka NGC 4552 once before. It lies in Virgo.

galaxy Messier 89 in luminance

Luminance only, 60 seconds subexposures, 10 stacked shots. FITS Liberator, Paint.NET. North is up; east is left.

Messier 89 is an intense elliptical. The core is incredibly bright and big. I'm no good at FITS Liberator and can't seem to draw out the edges for the galaxy. It looks nearly circular.

First viewed this target on 4 May '13.


Wikipedia link: Messier 89.

Friday, February 01, 2019

captured M58 (Halifax)

The Burke-Gaffney Observatory imaged Messier 58 for me. I wanted to revisit this galaxy also known as NGC 4579 in the constellation Virgo. From 4 July '10, I only had one log entry for M58.

galaxy Messier 58 in luminance

Luminance only, 60 seconds subexposures, 10 stacked shots. FITS Liberator, Paint.NET. North is up; east is left.

This is a fantastic barred spiral galaxy. It looks to be face on or nearly so. Love the detail in the grand arms twisting away from the prominent bar. The core is bright but compact. Beautiful.

To the south-east, a good distance away, is the tiny fuzzy oval of LEDA 1397945.

Near the gaggle of stars to the north-east, on the eastern edge, is a very small fuzzy oblong shape. SkyTools 3 Pro says this is LEDA 1400836.


Wikipedia link: Messier 58.

captured M59 (Halifax)

I ordered the BGO robot to image Messier 59. Another single-view Messier. I first took in this bright elliptical galaxy in Virgo on 4 July 2010.

galaxy Messier 59 in luminance

Luminance only, 60 seconds subexposures, 10 stacked shots. FITS Liberator, Paint.NET. North is up; east is left.

M59 aka NGC 4621 is big and bright with a fantastically bright core. It is oriented north-west, twisted slightly to the west or clockwise in this image.

To the north, and slightly west, a good distance away is a very faint round lint ball. This is LEDA 1398556.

IC 3665 lies to the south-west, a large diffuse fuzzy.

To the north-west is an elongated patch, oriented north-south. I believe this is LEDA 1398085. SkyTools 3 Pro also shows PGC 42679 here but it is opposed, oriented east-west. I don't see another galaxy here.

Nearby, further west, is the bright round diffuse galaxy IC 809.

Due north of 809 is a faint oblong but large fuzzy: PGC 42634.

The glow at the bottom-left corner of the image is NGC 4638...


Wikipedia link: Messier 59.

captured M91 (Halifax)

BGO gathered photons from Messier 91. I first viewed the galaxy in the Coma Berenices constellation on 3 May '13.

galaxy Messier 91 in luminance

Luminance only, 60 seconds subexposures, 10 stacked shots. FITS Liberator, Paint.NET. North is up; east is left.

A big propeller. This is an amazing barred spiral galaxy with a large and incredibly bright hub. There are two prominent arms in NGC 4548. It's difficult to see and I am having a hard time drawing it out but there's a large halo around the whole galaxy. We're face on.

To the north is a tiny fuzz ball: LEDA 169575.

PGC 41858 is far away to the west-north-west. Another tiny round fuzzy point.

Close to the big island universe, to the south, is LEDA 169578.

Almond-shaped PGC 41978 lies to the south-east. The canted galaxy is quite large and bright.


Wikipedia link: Messier 91.