Friday, July 31, 2020

sent article

After reviewing Rhonda's edits and verifying something subtle I had missed, submitted my latest column piece for the RASC Journal.

Thursday, July 30, 2020

watched for signal

I fired up the Deep Space Network live feed web page and waited... Watched for it at the Canberra station in Australia. 

signal from NASA spacecraft coming in

Ah ha! Incoming signal from the NASA Mars spacecraft, designated "M20."

watched Perseverance launch

Watched the NASA-ULA launch of the Mars Perseverance rover and Ingenuity drone.

Wednesday, July 29, 2020

warning sent?

Apparently, the ED sent a message to all the editors regarding the predatory publishing matter. He asked they forward the warning to all the contributors.

I did not receive any notice at or around this time... Curious.

tested sharing

Participated in sharing test conducted by Andrew with Tanya, Claudio, Ennio, and Ward. Tried to share the Moon but clouds interfered. Still, the "direct" sharing to OBS worked and I was able to do so via a 50-foot ethernet cable to my LAN.

caught up on comments

I apologise to my readers who leave comments. 

For some reason, the email address that was used to send me alerts about pending comments was deleted. Consequently, I missed out on a bunch of notifications. Sorry! 

Not ignoring you. Really.

I approved a whole bunch of comments going back a ways... And I added my email back into the blogger backend. So hopefully everything's on track again! 

Thanks for reading! Always enjoy your comments.

tested MallinCam Universe (Bradford)

When I saw the CalSky weather alerts for Bradford, I decided it would be a good time to test the loaner MallinCam Universe from Andrew.

I hatched the idea of setting up on the deck to get a bit more elevation. Improve my chances of seeing the gas giants. Or prolong the viewing windows. As I began hauling gear out back, I noted the Moon, just past first quarter. Oh, hello! You will serve as a target for aligning and focusing.
Instrument: Celestron 8-inch SCT
Mount: Vixen Super Polaris
Method: slewing and tracking with IDEA GoToStar
Completed a minimal setup. Celestron 8 on the Vixen Super Polaris, no computer for targeting, not needed, I'd do everything from the hand controller. Dew gear, if needed, left in case. Although I did install the dew cap (happy Mr Briggs?). One eyepiece to aim but then I removed the ocular and mirror diagonal. MallinCam. It's a beast. Power and data cables. Win 10 computer 64-bit for MallinCam ops and image capture. Look at that, the image was near focus! Good! That answered a question immediately, I would not need an extension tube. Bungee cords and tarp for later...

hooked up, it works

Sent Andrew a pic to show everything was working, at least in terms of capture.

It occurred to me that the timing of this was eerily appropriate. I looked in Mare Nubium. Well, look at that! There's the Straight Wall. Easy to see. Ha! Is that a life list first? [ed: Nope. Viewed from Toronto in August 2009... 11 years ago!]

Installed my custom extension cable for the hand controller. Helped me avoid inducing vibration into the mount. Brought the HC near my comfy chair.

Rotated the camera 90° to better match the sky view.

camera in a better orientation - USB up!

Noted the orientation of the USB cable.

Oh my. Lots of dust on the sensor.

screen snap from the MallinCam Universe app

Started exploring the software. Ugh. Painful memories starting coming back. Awkward weird strange software written with little regard for standards and common conventions. I waded through the user guide, as best as possible. It's no great shakes either. Why is the control panel so tall or long. Pain in the ... wrist... to constantly scroll up and down. Why no maximise, minimise, and restore buttons on the view window? Why does the Change Exp button text vary when you press it?! What does the Cross checkbox mean? Where is the text label field? Why does the pin feature not work properly? Where's the dark mode switch?! [ed: Which version am I using?]

Was the view correct, I wondered. Tried the Horizontal and the Vertical buttons. Unchecked was fine.

Tried recording video. Strangeness on the first one, zero bytes. The other recorded AVI files seem appropriate sizes but threw errors on playback or report weird durations. Something about encoding and compression?

screen grab from the second Moon movie

Southern region is lumpy.

Tried to record a movie on a zoomed in region. Didn't work. Colour sliders worked but I did not like the colour tone. Tried the "one touch" white balance. Weird result. Ugh.

sharpening set to medium

Tried the sharpening option. High up was too aggressive, medium was good.

Dialled out the drift as I had not aligned to Polaris. Minimised the drift.

Lathered up with repellent.

Rhonda joined me on the deck.

I played Clair de Lune on my phone.

The Moon started slipping behind clouds and apple tree leaves. Waited for Jupiter to emerge from its arboreal occultation.

Tagged Jupiter as it cleared the tree. Tried to record Jupiter video but the app kept reverting the filename entry back to "Moon4." Quit the app and restarted. Working. Sheesh.

Jupiter over-exposed at low power

With a long exposure and high gain, the moons were visible but the planet blown out. Too small.

Jupiter over-exposed at high power

Installed the PowerMate to double the magnification. Better.

surface details visible on Jupiter

Played with the exposure, gain, gamma, to get a decent view of Jupiter proper. But the moons disappeared of course.

cropped screen grab from the MU app

Finally Saturn appeared. Waited for good seeing to catch it.

Saved my settings in the app. Hopefully I'll be able to recall them later.

I fancied playing a bit with the recorded video. RegiStax, right, for planetary? It's been a while.

Saturn seemed quite orange to the naked eye and Jupiter also appeared a little bit yellowed. I wondered if there was smoke or particulate but didn't see any nearby fires.

It was a beautiful night. Pleasant temperature and not humid. Checked the conditions in Good To Stargaze.

main screen grab from GTS

The good to go indicator showed. I'm on it!

detailed screen grab from GTS

The detailed report showed the humidity around 75%. Didn't seem that high.

A few minutes before midnight, I dismounted the camera. Installed the baader planetarium eyepiece. Then the Pentax. Rhonda and I enjoyed the view, identified the many moons of Saturn, and tagged the C ring. I was very happy to see it with my eyeball! Beautiful!

Clouds returned which I took as a cue.


As I moved equipment back indoors, I ruminated on the MallinCam. Certainly the camera is significantly better, much better resolution, no obvious hot pixels. Great that a proprietary RS-422 cable is no longer needed. But the software continues to be extremely clunky. And the documentation is not good. It was terrible before with the older systems. This is a step up, clearly a lot of work went into it. But this is not the way to do it. Of all the questions I had and all the searches I conducted, the manual only gave me about 10% of the information that I needed. It's a shame. Alas, it works satisfactorily and only failed once, directly. 

There is the unresolved issue of badly constructed AVI files though... I have a feeling all the recorded video I captured is not good.


My persnickety attitudes about documentation and software quality aside, tonight was an experiment night. I wanted to test the MallinCam Universe on my rig and sort any major issues. There were none. It works, I didn't need an extension tube, my magnifier worked, I was able to wrangle the software. Another test was to gauge the visibility of Jupiter and Saturn from home. Quite good from the deck.

Next things to figure out are how can video from my laptop get through the internet to Andrew. Will it work through my wifi or will I need to make a hardline connection?


At 10:14 PM, Rhonda spotted the ISS at the end of its pass.

Monday, July 27, 2020

more converts

Elaine and Tony send me one of their images. Hey! That's Albireo. Ha ha. I've got them drinking the Kool-Aid.

Sunday, July 26, 2020

found final dew heater build video

Found the edited version of my online video presentation for how to build a custom dew heater. I noted the thumbnail cutaway image I recently made. Thank you, Andrew.

custom dew heater guts

I delivered this presentation on 17 Jun within the Recreational Astronomy Night virtual meeting for the RASC Toronto Centre.

Saturday, July 25, 2020

found GRS wrong in Stellarium

Chris and I compared notes and I noticed the GRS position wrong in Stellarium.

Version 0.20.2 showed:
2014.09.01 00:00

To get it right, we had to use:
2020.06.01 00:00 says its around 333 right now.

StarryNight, SkySafari, SkyTools, S&T's Javascript tools all agree.

a water world

Here's a lovely water world. What would it be like to live on a world of mostly water, blue oceans, and... Wait a second! That's Earth! Hello, Earthlings!

water world

Spotted this image on the interwebs. I don't know all the particulars but it was obviously captured by a satellite positioned over the Pacific Ocean. And apparently doctored to remove all the clouds. And the reflection of the Sun... Still, fascinating.

trouble out east

Tried for more panels in the East Veil nebula but the returned images (from BGO) have lots of problems. So I think I'll throw the whole batch out and try again...

Thursday, July 23, 2020

deciphering comet names

Got to thinking. Dangerous, I know. 

I remembered Chris saying, during our comet presentation, that C/ was used on comets that were new to us. If orbital data indicated a return trip, they would be designated with the P/ prefix. But seeing numbers in front of P and new designations for interstellar comets, I thought I'd do a deeper dive.

I read information at the amazing wikipedia on naming conventions and at the Minor Planet Center, which is the official source, part of the International Astronomy Union. Still, some things remained unclear and the MPC information was very technical. I found an old article by Phil Plait. He's usually brilliant at clarifying things but he did not address the prefix number on P comets. A piece at Harvard University was helpful.

I think this is the nomenclature rule or format:


  • # is the sequential observation or discovery number, for periodic comets
  • T is type 
  • YYYY year of discovery, often omitted for periodics
  • (the space is required between the year and period)
  • Z is the period within the year
  • 9 is discovery number within the Z period
  • DISCNAME name of discoverer(s), shown parenthetically
Further, the types are:
  • A: re-classified as an asteroid
  • C: non-periodic comet
  • D: broken up, lost, crashed
  • I: interstellar
  • P: periodic comet (with a relatively short period, say 100 years)
  • S: satellite to a parent comet
  • X: unreliable data
And for the period within the year and month, with each month broken into two parts:
  • A: first part of January
  • B: last half of January
  • C: first part of February
  • ...
  • I and Z are not used
Regarding the discoverer naming. If one person is associated with the comet, their surname may be noted. When there are multiple discoverers, up to two or three names may be shown, with hyphens. It is common for human names to be shown with an initialised letter. e.g. Churyumov-Gerasimenko. Robotic or automated systems are discovering comets in which case the system name is noted, usually with capitals. e.g. ATLAS or Pan-STARRS.

Make sense? Sheesh... When I looked at some examples, even when "the rules" was being closely followed, I found a bewildering array of names. Let's have a look, shall we?

C/2020 F3 (NEOWISE). In the news of late. Maybe you've heard of it? Nice and easy. I try to use the proper name when referring to it, sometimes shortened to C/2020 F3, or the full designation. Many casually call it "comet NEOWISE" which is acceptable, for now...

C/1995 O1 (Hale-Bopp). Many are comparing "NEOWISE" and "Hale-Bopp," with C/2020 F3 putting on a comparable show in the sky. Officially, "Hale-Bopp" is known as C/1995 O1. This is a comet on a non-return path, discovered in 1995, in the bottom half of July, by astronomers Alan Hale and Thomas Bopp.

D/1993 F2 (Shoemaker-Levy 9). A rather famous comet 27 years ago that made all the headlines was "Shoemaker-Levy." Discovered by Carolyn and Eugene Shoemaker and David Levy in 1993, this comet was captured by Jupiter's tremendous gravity well and ultimately crashed into the planet. Given it no longer exists, the D/ code is applied. This comet is no more! It has ceased to be! This is an ex-comet!

Now here's a good example of where we shouldn't casually refer to this as simply "Shoemaker-Levy" as the Shoemaker duo with Levy discovered many comets such as Shoemaker-Levy 1 (from 1990), Shoemaker-Levy 2 (also 1990), or say Shoemaker-Levy 3 (from 1991).

OK. So far, so good. 

Still with me?

But then I thought about other comets I've seen (or imaged) like 103P/Hartley 2 or 46P/Wirtanen. Wait. What? This convention seems completely different! Periodic comets are preceded by a number and this seems to be a simple sequential number. So 1 would be the first discovered periodic, 2 would be the secondary short-period returning comet, and so on. Begs the question, who keeps track? I suppose the IAU.

46P/Wirtanen. This appears to be slightly casual description but wikipedia shows a dozen alternate designations! I believe the official IAU tag is 46P/1948 A1. It seems to me that these comets are expressed often in a casual way without the discovery year and without parenthesis about the discoverer's name.

1P/1682 Q1 (Halley). Ah. The famous Halley's comet. 1P indicates it is the first known regularly returning comet. Initially discovered in the 17th century. Now what can be further confusing about periodics is that the quoted year number may appear different. For example, 1P/1682 may be shown as 1P/1986. That's because the famous 75-year naked-eye comet was last seen in '86.

1I/'Oumuamua. Previously C/2017 U1 (PANSTARRS). Discovered by Weryk using the Pan-STARRS system in Hawaii. Ugh. Certainly a most amazing object but it's bending the rules. The 1 indicates the first of its kind. Capital I is for interstellar as it has been determined from it's hyperbolic path that it ain't from 'round here. I found this moniker widely used but again I believe it is a contraction. It appears the official IAU label is: 1I/2017 U1 ('Oumuamua). OK, good. By the way, Weryk's name is not used; the IAU decided on the Hawaiian word for "scout." Also note the first character is not an apostrophe; it is an 'okina and is pronounced as a glottal stop or plosive. 

Note, the second configured interstellar interloper is 2I/Borisov.

Confused? I think the nomenclature I show above works. But it is certainly clunky. It's better than the past systems for sure but still, it ain't easy.

I just read the IAU page on the Naming of Astronomical Objects. Even their initial description does not seem to address numbered objects. But later, they said, "When a periodic comet is observed after its second apparition, the MPC gives it a permanent number indicating the order of the discovery." Ah. 

So, it strikes me that there's a fork, a split, at the high level. That is you have periodic comets and... others. As Chris noted, C or P types. But it seems the P comets have numbers. It was the Harvard information that emphasised this division but in a way that made sense given the numbering. I think the right way to think about it is we have numbered comets and unnumbered comets.

I made an infographic. I show the hierarchy, with subordinates, and examples. I also show "migration" arrows, for re-designations or reclassification.

comet hierarchies and re-designations

There are two main classes, unnumbered or numbered.

Under unnumbered, we have C/ class, the non-returning comet. This appears to be the initial designation applied to all new discoveries.

Also within unnumbered, we have the dead, deceased comets, the D/ class.

Under numbered, we have the P/ class with the preceding IAU assigned sequential number.

And finally we have the I/ class, interstellars.

The dotted arrows indicate how things might change. A non-return comet can disintegrate or fall into a gas giant. Bye bye! Could happen to a periodic too.

A comet initially discovered, after we get some good orbital data, or after perturbations, might turn into a periodic. (I supposed the opposite could happen too... now that I think about it.)

I think I've got it. Does this help? It works for me, demystifying all the variants in comet designations.


A subtext of all this is to remind people to be careful only using the discoverer's name. For example, don't say you shot an image of comet PANSTARRS last night. We won't know which comet you're talking about.

corrections to comet article

RASC Toronto Centre was contacted (at the eleventh hour mind you) by CTV News to provide information about comet C/2020 F3 (NEOWISE). Good to hear that they are reaching out to an official source, subject matters experts, for correct, accurate, and reliable information. Unfortunately, they put a spin on it that's awkward for RASC. So, it's time to do some more myth-busting...

The piece is in the SCI-TECH | News category on the CTV News web site. By Meredith MacLeod. Originally published on Wednesday 22 July 2020 at 10:03 PM EDT. It was updated the following day. RASC requested further updates but there was no reply.

Title. "Comet at its closest to Earth before heading out of sight for 6,000 years." OK. That's a bit of selling newspapers. But it does convey urgency, the time is nigh, get out there and have a look, it is fading. 'Cause if you miss it, you'll have to wait 6 millennia before you can see it again. Right. The author could have just said, "Comet at its closest to Earth and will continue to fade."

Opening volley. "Comet NEOWISE, a massive burning 'icy snowball,' will be closest to the Earth Wednesday night, before its orbit begins to take it out into the solar system."

Ugh. Burning? Really? Hopefully the reader will note in the mixed metaphor that the quotes are around icy snowball and will then realise an interviewee provided this description but the article author added "burning." Comets don't burn. This creates for me an image, like from a cheesy sci-fi B movie, of a flaming and smoking ball (hanging from a wire) flying through space. Comets sublimate. RASC told them that but they didn't say it. Does Ms MacLeod not understand sublimation? Is it not exciting enough? She does talk about this shortly... sorta.

Massive? No. That creates this an Earth-crushing, near-miss scenario in the mind of reader. MacLeod does quote NASA later and they reported it as "five kilometres wide." So, to keep this in perspective, the Earth is over 12700 km in diameter and the Moon is almost 3500. This comet is small. Also, a science writer should use "massive" when referring to mass or weight. This is a casual usage meant to allude to the size or dimension. The sky is not falling.

Also, scientists speculate that the dinosaur-killing object that hit the Earth at Chicxulub impactor basin was likely 170 km in size. 

I have my personal pet peeve triggered in this opener but she does correctly use the official, proper name for the comet two paragraphs later. It's not "comet NEOWISE." It's comet "C/2020 F3 (NEOWISE)."

Heavenly. The fourth paragraph begins "The sun is responsible for the heavenly glow that has been visible from Earth with the naked eye for about 10 days." I took this from a spiritual context and immediately my guard went up. I didn't think it appropriate or relevant from a SCI-TECH contributor in a news media outlet. Comets are not about religion or pseudo-science. This is about solar system objects. The emphasis should be on science and facts.

Glow. "The solid, icy and rocky surface of the comet has got so hot that it has converted to gases, which glow bright and illuminate the debris that is falling off comet..." Grammar issues aside, I don't think this conveys things correctly. MacLeod suggests the comet material is producing its own light. Nope. The Sun emits light. Comets reflect light. They seem to glow to the viewer. Again, I wonder if the author is imagining an object heated to such an extra temperature that it produces a glow. This is not metal being welded. It is not like your stove-top element. It's a dirty snowball leaving a dust trail and an ion trail and sublimating due to solar heating. An ice cube from your freezer will slowly melt to water. A comet's ice phases immediately from solid ice to gas. See the wikipedia article on sublimation for more information.

Hot gases. "But as the comet continually moves further from the sun, it is cooling off, and those hot gases will dim." This further supports my suspicion that the author doesn't understand the processes happening on a comet. The gases are not hot. The gas is not glowing.

Chris Vaughan is cited in the article. Props to RASC Toronto Centre. Represent! But it's a double edged sword. A casual reader taking all this at face value might in turn think that RASC told MacLeod about comet properties. In fact Chris talked about sublimation in some detail.

Viewfinder. MacLeod refers to an Ontario photographer not knowing if he "captured the comet until he checked his Nikon’s viewfinder." Nope. He would not have been able to see it in the viewfinder, certainly not if he couldn't see it with the unaided eye; he saw it on the camera screen after shooting. Maybe even his computer screen. Minor point.

She then quotes the photographer. Ah. It is he who referred to the "heavenly" object above our "earthly" domain. Perfectly fine, of course. Here is a person marvelling at all of his god's extraordinary and wonderous creation. Indeed.

I know RASC referred MacLeod to photos captured by RASC TC members. Shame that one of those was not included even through the shot from Dundas, Ontario is nice.

A correction was made to the article noting that Halley's Comet, last seen in 1986, was not the last naked eye visible comet. But MacLeod does not quote which ones have been easily spotted in the last 30 years. Hale-Bopp? C/2011 L4 (Pan-STARRS)? That would do some level-setting. Yes, bright comets are rare, and you need to look at them whenever you get a chance. And, yes, they are quite unpredictable. Mmm, to be clear, their brightness is difficult to predict. But comets are common and frequently visit the inner solar system.

So. As usual, I feel betwixt and between. I want to convey astronomy and science information to all, share the joy and excitement of the natural world around us. RASC wants to do that. And this comet has been fantastic. But RASC wishes it could have had an editorial review of this article before the piece went out. It's clear Ms MacLeod was collating quickly, does not know a lot about the solar system, and was late for a deadline. We sadly received slapdash output with a facsimile of the truth.

very clear (Bradford)

While enjoying a burgundy cherry, I took in the thin Moon and Jupiter. Rhonda helped me find Saturn over the Sabella sign. There's a comet up there somewhere... Very clear skies...

update on predatory publishing scam

Received a quick note from the ED.

Hi again Blake,

Just letting you know that I'm in the process of crafting a warning to all our contributors and editors.  Once again, thanks for bringing this to my attention.


Philip Groff, Ph.D.
Executive Director, RASC

Good stuff!

explained comet magnitudes

There have been a few remarks about comet magnitudes. Rich's question today compelled me to try to clarify things. "Why there are... dramatic differences between [different sources]?" I posted the following on the RASC Toronto Centre forum.



ONE - extended

First. Comets are “extended” objects. I.e. they are big objects that take up many arc-seconds or arc-minutes of space on the celestial sphere. Like galaxies. They are unlike stars which are point-source objects. [ed: This is also true for planets—point sources.]

When we measure the magnitude of a star, it’s simple. All the light is concentrated into a small pinpoint. But the light for a comet or a galaxy is spread out. When we measure the magnitude for extended objects, we get a number that is the aggregated or integrated result.

Imagine this. You have grains of sand on some black fabric. All the grains are used to measure the magnitude. Stack the grains into a compact small pile, as tall as possible, and you clearly have a high concentration of dots in a small area, easy to see, as a group. Now swish the pile, run you fingers through the grains, and spread the pile out, over a large area or over much of the fabric. It’s the same number of grains but now widely distributed. Harder to pick off, harder to see, especially from a distance. Just like a galaxy or a comet and its tail.

So that’s the first key point. Comet magnitudes are extended object magnitudes.

A galaxy or comet of magnitude 5 is much more difficult to see compared to a magnitude 5 star. The star is easy, while small. The comet (with tail) or galaxy will need a dark sky, good transparency (as Frank mentioned) excellent vision, averted vision techniques, maybe all four.

Now, here’s a brain-bender. Galaxy size, in square degrees, does not change. So the magnitude value will stay constant (assuming we measured it right to begin with). Comets change in size or area…

TWO - source

Now, the next part is data source. What does Telescopius use for it’s data source and when was it updated? (Razvan noted that: JPL/NASA.) You always have to ask yourself that of any resource you consult. And that’s why I don’t use or relay on just one.

People like Seiichi Yoshida ( and Greg Crinklaw ( consult reliable sources. The official source of small body solar system information is at the Minor Planet Centre ( run by the IAU. I would assume Telescopius uses official sources but off the top of my head, I dunno.

There’s that new (to me) web site COBS ( where observers submit observations on comets. That’s empirical data. That said, when objects are imaged for magnitude, you need to know what filter method is used… That’s another rabbit hole!

THREE - currency

You saw me make a mistake yesterday. I shared the comet ephemeris data from SkyTools (by Crinklaw) but I forgot to update it before posting. It was week-old data?

Astronomical data gets updated over time. With minor bodies in particular, asteroids and comets, they are being perturbed by big objects in the solar system. The Sun dramatically affects comets. Jupiter, though far away, is affecting all asteroids and comets. We saw 27 years ago what happened to comet D/1993 F2 (Shoemaker-Levy 9)…

So orbital data is regularly updated for all these types of objects, hence the existence of the MPC. With more and more observations of an object, we can increase our confidence in the orbital parameters and we can classify orbits as known or certain. There’s a rating scale.

For comet C/2020 F3, we know now that its orbit period has changed with this recent perihelion and it is now calculated to have a 6000 to 7000 year period. Because the period is so long, if I understand the conventions properly, it will NOT receive a P/2020 F3 designation…

That’s why you need to update your planetarium software to get the correct and accurate path for comets and asteroids.

Sidebar: Look up the diameter of Pluto. Go ahead! You’ll find a LOT of different values…

FOUR - cats

And finally there is the special case of comets. They are obviously affected by the Sun in terms of heating, outgassing, tidal, and sublimation processes. Closer to the Sun, the brighter it gets; further out, it dims. They seem to be fragile. So we get disintegration events which further dims the object. And then, mysteriously, unpredictably, comets brighten. I don’t know if scientists fully understand why but imagine there’s a pocket of ice trapped into a hard rock shell and it cracks open due to solar tidal forces and all the ice begins leaking out. I can see that type of thing happened and now more ice is added to the comet tail brightening it.

I think there’s been changes happening at the comet surface and interior that are causing the brightness to shift and change. So, again, we need to update our planetarium or planning apps to show this new data. And we need to corroborate values from our web resources. It can change every day!

News media outlets should not be used as official sources for brightness indicators 'cause they’re trying to “sell newspapers.”

Summary. This is what makes comets fascinating to observe because we never know what’s going to happen exactly. We don’t know exactly where they are from. Probably the Oort cloud. We don’t know if they will survive perihelion. C/2020 F3 did. It is difficult to measure the magnitude. The core is bright. The tail? Doesn’t exist, doesn’t show, is small, is big, has multiple trains (ion, dust), is growing. Ugh. I wouldn’t want to be in charge of measuring and recording this. Comets are often described as dirty balls of ice. They don’t roll off an assembly line with the exact same specifications. So every comet is different and its behaviour will be correspondingly random!

Bottom line is, all our resources like aerith, SkyTools, Telescopius, CalSky, SkySafari, are all dependent on humans updating data according to the latest discoveries and measurements.


Some additional thoughts.

Be aware of the quoted magnitude for comets (or any object). Is it the absolute or apparent value provided?

Periodic comets, one could argue, are getting smaller and smaller with each perihelion pass. So, arguably, dimmer each time.

By extension, any comet will get dimmer over time as material falls away, breaks off, and sublimates.

Found an interesting article from 2006 at Sky & Telescope on methods or techniques for assessing the brightness of a comet. Early on they say, "For centuries the reported magnitudes of naked-eye comets were very ambiguous."

Remember, atmospheric extinction becomes a significant factor for objects close to your horizon. People reporting magnitude estimates should also quote celestial altitude.


On November 2020, I found a post by Pedro of Simulation Curriculum in Cloudy Nights where he told the MPC their data was wrong! They fixed it. But it made me wonder about the cascading effect with the new data. It might not happen immediately across dependent apps...

Wednesday, July 22, 2020

first draft nearly done

Did some more work on the DDO telescope 3D model. Added the interface between the OTA and mount, with articulation in mind. Added the upper bearing with pin. Added a base plate for the piers. Adjusted the colours... It looks good, I think!

74-inch telescope, well, it's only a model

With a few little additional bits, I'll be ready to print my first draft...

It's going to be a slippery slope if I feel the need to include more detail. It currently is without secondary mirror, spectrograph, motor drive, setting circles, finder scopes, and all the counterweights....

learned about predatory publishing

I don't know how exactly but my BS radar triggered immediately (fortunately). A few remarks in the strange email sounded very peculiar. Suspicious, I did a bit of digging and found suggestions that this is a fake predatory journal.

They charge exorbitant fees. They prevent an author from republishing. They ignore tear-down requests. 

This group has clearly harvested data about me and pitched me through the Journal of the Royal Astronomical Society of Canada. I was worried this might happen to happen to other contributors to the JRASC.

I'd hate to learn that any of our other writers were scammed or worse paid out their own money.

Frak. Scammers everywhere!

I informed the executive director of RASC...

created a comet plot

And here's the updated chart. Covers 21 July to 4 August.

comet path for the next week or so

From SkyTools 4. Orange circle is a binocular field.

comet particulars

Here's the comet C/2020 F3 ephemeris data for the next 30 days, courtesy SkyTools 3 Pro, for the city of Toronto.

All rows are for the local time 22h15m EDT.

RA and Dec are J2000.

Date RA  Dec  Con Size Mag Alt Azm
Jul 19 09h25m38.4s +47°41'38" UMa 1.2' 2.4 +19°59' +318°04'
Jul 20 09h47m23.0s +46°57'50" UMa 1.2' 2.5 +21°41' +315°18'
Jul 21 10h08m32.4s +45°55'51" UMa 1.2' 2.7 +23°14' +312°21'
Jul 22 10h28m45.6s +44°37'32" UMa 1.2' 2.9 +24°38' +309°17'
Jul 23 10h47m47.3s +43°05'16" UMa 1.2' 3.1 +25°51' +306°07'
Jul 24 11h05m28.4s +41°21'50" UMa 1.2' 3.2 +26°52' +302°53'
Jul 25 11h21m45.4s +39°30'05" UMa 1.2' 3.4 +27°41' +299°39'
Jul 26 11h36m38.9s +37°32'46" UMa 1.1' 3.6 +28°17' +296°27'
Jul 27 11h50m12.4s +35°32'19" UMa 1.1' 3.8 +28°42' +293°20'
Jul 28 12h02m31.3s +33°30'52" UMa 1.1' 4.0 +28°56' +290°19'
Jul 29 12h13m41.8s +31°30'09" Com 1.1' 4.2 +28°59' +287°27'
Jul 30 12h23m50.6s +29°31'31" Com 1.0' 4.4 +28°54' +284°44'
Jul 31 12h33m04.0s +27°35'59" Com 1.0' 4.6 +28°40' +282°11'
Aug  1 12h41m28.0s +25°44'16" Com 60" 4.7 +28°20' +279°50'
Aug  2 12h49m08.1s +23°56'52" Com 58" 4.9 +27°53' +277°39'
Aug  3 12h56m09.3s +22°14'02" Com 56" 5.1 +27°22' +275°39'
Aug  4 13h02m36.1s +20°35'54" Com 55" 5.3 +26°47' +273°49'
Aug  5 13h08m32.2s +19°02'29" Com 53" 5.5 +26°09' +272°09'
Aug  6 13h14m01.2s +17°33'43" Com 52" 5.6 +25°28' +270°39'
Aug  7 13h19m06.1s +16°09'27" Com 50" 5.8 +24°46' +269°17'
Aug  8 13h23m49.5s +14°49'30" Com 49" 6.0 +24°01' +268°03'
Aug  9 13h28m13.7s +13°33'42" Vir 47" 6.1 +23°16' +266°57'
Aug 10 13h32m20.8s +12°21'48" Vir 46" 6.3 +22°29' +265°57'
Aug 11 13h36m12.6s +11°13'36" Vir 45" 6.5 +21°42' +265°04'
Aug 12 13h39m50.5s +10°08'54" Boo 44" 6.6 +20°55' +264°16'
Aug 13 13h43m16.1s +09°07'28" Boo 43" 6.8 +20°08' +263°34'
Aug 14 13h46m30.4s +08°09'05" Boo 41" 6.9 +19°20' +262°57'
Aug 15 13h49m34.7s +07°13'35" Vir 40" 7.1 +18°32' +262°24'
Aug 16 13h52m29.7s +06°20'45" Vir 39" 7.2 +17°45' +261°55'
Aug 17 13h55m16.5s +05°30'26" Vir 38" 7.3 +16°57' +261°30'

You will note the magnitude is dropping by 0.1 or 0.2 per day.

Currently in the magnitude 3 range which is well within the limit of unaided eye visibility.

strange message

I received a strange message today... I discourage you from following any of the links. I show it here for completeness.

Subject: Dear Nancarrow, Blake: Submit Article and Join Our Editorial Board/Reviewer Team -- Take Control of Your Mount.

From: Caroline Williams <>


American Journal of Astronomy and Astrophysics

ISSN Online: 2376-4686   ISSN Print: 2376-4678

√ Open-access (OA) Journal

√ Peer Review

√ 40-90 Days' Fast Publication

Dear Nancarrow, Blake,

Hope you had a great time.

We have read your paper titled "Take Control of Your Mount.", which has been published in /Journal of the Royal Astronomical Society of Canada/, and the topic of the paper has impressed us deeply.

Due to your rich research experience and excellent academic accomplishments, we will feel honored if you could contribute papers to our journal and join as an Editorial Board Member/a Reviewer.

Contributing Your Unpublished Manuscripts

Aiming at publishing academic articles, /American Journal of Astronomy and Astrophysics/ can make specialists in the related fields closer to the latest scientific research. Due to the advance, novelty, and potential extensive application of your research results, we sincerely invite you to send other unpublished articles of similar themes to the journal. We are also looking forward to receiving your further research on the topic of the published paper.

Click the link below to learn more information:

On behalf of the Editorial Board of the journal, we feel much honored to invite you to join us as one of the editorial board members or reviewers. Given your academic background and expertise in this field, the Board believes that you may be a suitable person for this position. We hope that your position as one of the editorial board members/reviewers will promote the development of scientific research in your field.

If you want to join us, please click the following link:

Be One of the Editorial Board Members/Reviewers

Please kindly let us know if you have any question.

All the best,

The Editorial Office of American Journal of Astronomy and Astrophysics

Right away, I was suspicious. So started some digging...

[ed: Learned this is predatory publishing!]

more remnants

Another big run at the BGO. Received 6 jobs, all for the Eastern Veil, all with hydrogen and oxygen. This provides 11 of the 12 panels I had planned in the mosaic. But now I wonder if I need another 3?! There seems to be more wisps off to the south!

Tuesday, July 21, 2020

saw doodle on Eryurt

Spotted the Google Doodle on my phone browser. It shows a woman looking into space. This was in recognition of Dilhan Eryurt.

Google Doodle for astrophysicist Eryurt

Eryurt was a Turkish astronomer, specialising in astrophysics, who made major contributions in our understanding of the formation and evolution of the Sun and other main sequence stars. See the wikipedia article for more information.

Monday, July 20, 2020


Happy Saturn Day! Saturn is at opposition, i.e. we are rather close to the ringed planet.

Sunday, July 19, 2020

the bull

Didn't clue in. Duh. One of the Formula 1 teams running in the weird 2020 season is badged Alpha Tauri. I noted the charging bull in the logo. How about that. Learned they are also owned by Red Bull. Ah. I see. Check the wikipedia article for more info.

there is hope

Just missed the Emirates launch to Mars. Glad to see the Al Amal orbiter is off to a flying start. See the mission page for more info.

run of the robot

Weird. Felt like no one was around and I had free run of the BGO. Submitted 6 jobs for the new mosaic run of the East Veil and 5 were completed, all for hydrogen and oxygen.

Saturday, July 18, 2020

heard from number 1 sister

Even my sis is into it!
Al, Steve and I watched the comet tonight at Bob's.  It was so cool!  We had our binoculars and spotting scope.  I liked it better with binoculars.  We also had the scope on Jupiter and saw 4 of its moons.  The mosquitoes were brutal though.
I told her to try a photo with her new camera.

really, really hot campfires

Images are starting to come in from the European Space Agency's Solar Orbiter probe. These are the closest images of the Sun, to date. And the level of detail is fascinating. One of the most striking things are the appearance of these very small solar flares which some are describing as campfires!

close up image of the Sun and its mini-flares

More interesting stuff will be coming down the pipe, particularly when the probe shifts to view the polar regions of the Sun.

Check out the ESA SO page for more info...

new astro-mask

Today, I wore my astro-themed face mask made by Mom.

would have been

I guess today would have been the awards, open house, and picnic. Last year at the DDO; would have been back at the CAO. Kites, rockets, nature hikes, campfire, big meat barbecue! Day and night observing. Looks like a lovely day. Missing my astronomy friends...

Friday, July 17, 2020

comet success! (Bradford)

The skies looked great!

We headed to the water tower again, behind St Teresa of Calcutta, armed with bug repellent, light clothing, tripod, binoculars, and astronomy apps.

I scanned the sky with the binoculars, about 20 degrees up, but couldn't see it.

Rhonda checked her phone.

9:50. Looked straight down from Dubhe. Made a brief stop at θ (theta) Ursae Majoris. Continued down to the wide pair of Talitha. Got it! The comet was obvious down and right. The core of C/2020 F3 (NEOWISE) was not as bright as the main star of Talitha but close to the magnitude of the dimmer star. The tail was obvious but dim, angled up and slightly to the right.

comet below Dubhe on mobile phone app

Rhonda saw it naked eye first. It took me a lot longer.

The bugs were ferocious.

10:10. One last look in the Bushnell InstaFocus binoculars. Very nice. Much better against the darker sky!

OK. No more bloodletting!

10:13. Spotted three moons of Jupiter, to the right or west. [ed: Europa was furthest out, then Ganymede. Io was tricky, close to the planet.] Couldn't see the fourth. I wondered if it was on the left. Flaring in the specs.

Orange Saturn showed no features at 7x but it was clearly not round.

We packed up. Near the big coniferous tree, blocking the street light, the comet was easy to tag with the unaided eye. The tail was spectacular, curving upwards into the indigo sky.


And a neat experience to see this comet again, now in the evening!

found Aug Journal

cover of the Aug 2020 RASC Journal
Found the August 2020 Journal online when I logged into the RASC national site.

Lovely photographs as usual. Alister Ling submitted a paper on noctilucent clouds which looks fascinating. Mary Beth Laychak provided an update on the CFHT. Looks to be another good read.

In my Binary Universe column I talk about Solar System Scope, an interesting and fun tool for exploring the solar system and beyond. I specifically tested the full Windows product, version 3.2.3, downloaded and unlocked, which is faster and displays at a higher quality than when running in the browser. There are apps for mobile devices (but I haven't tried them).

It's good for education and public outreach too.

Wednesday, July 15, 2020

helped backstage

Helped with the RASC Toronto monthly recreational astronomy night meeting. Andrew asked me to be the questioner so I relayed queries from the YouTube chat as well as tossing in a few of my own. Lots of tech glitches tonight, unfortunately.

Tuesday, July 14, 2020

strike one

Struck out tonight. We returned to the water tower in hopes of seeing the comet but low clouds scuppered our attempt. Probably a good thing as I forgot my bug spray and it seemed like every mosquito in town decided to chomp on my fingers and forehead. Sorry. I'm saving my blood for my human donation tomorrow...

Monday, July 13, 2020

lined up for Aug TSTM

Was asked by Markov to deliver The Sky This Month presentation for August. I accepted. I'm on deck for Wednesday the 19th. I invite you to tune in for the live online webcast on the RASC YouTube channel.

free SkySafari updates weekly

I just learned that SkySafari Basic (the free product) is updated weekly.  Pedro said, in the Sim Curr forums, that you can uninstall and reinstall to force an update. He intimated they are going to change the update frequency. That'd be good. When I checked SS-B last week, no comet. Today, I found C/2020 F3 (NEOWISE) listed in the search and selectable.

Sunday, July 12, 2020

check out the Skylights

Check out my buddy Chris's Skylights for this week. In addition to all his general what's up astronomy info, he has lots of info on the comet... Of course, Jupiter and Saturn are pretty amazing right now.

reviewed article, late

Proofread my Journal article... Down to the wire.

created a new plot

Comet C/2020 F3 is transitioning to the evening sky... soon. It is officially in Lynx now.

comet path for the next few days

You can see it's climbing. Normally a celestial object higher is easier to see.

And the comet is drawing closer to the Earth. Perihelion was on 3 July. Perigee is coming up soon. Wikipedia says, the "closest approach to Earth will occur July 23, 2020, at a distance of 0.69 AU (103 million km)."

But the comet is moving away from the Sun. So, it will be fading.

Hopefully, we'll experience a nice balancing effect...

good sources

Need more information on comets with visibility assessments? I regularly use Yoshida's aerith site and Crinklaw's comet chasing page.

Want to submit your observations, head over to COBS. This one is new to me.

Also, aerith and COBS have magnitude charts... Happy hunting!

where is C/2020 F3 now?

If you want official and detailed information for the C/2020 F3 (NEOWISE) comet, check out the SSD page by NASA. This is the Solar System Dynamics web site by the Jet Propulsion Laboratory.

C/2020 F3 path through inner solar system

A great feature of this site is the ability to show a 3D orbit diagram that you can pan and tilt.

Friday, July 10, 2020

tried the solstice

Tried Solstice by Great Lakes Beers. A bourbon barrel-aged imperial stout. Very good.

Solstice beer front

I've had a few of their products, such as Pompous Ass and Shinny Pants.

Solstice beer back

Ooh. Vanilla beans! Paired well with barbecued local sausage.

Wednesday, July 08, 2020

made a comet video

Andrew thought we should help people with their comet questions so suggested Chris and I make a video. We quickly discussed what we should cover, while trying to keep it short and zippy, and put together a script. Watch it here. About 35 minutes.

Video produced by Betty and Andrew on the RASC Toronto YouTube channel. Hopefully the first of a series...

Tuesday, July 07, 2020

enjoyed the morning show (Bradford)

We headed to the water reservoir for 4:00 AM, taking in a bunch of planets to the south, Jupiter, Saturn, and Mars, with the Moon in between.

Venus was rising, orange-tinted. There were low clouds in the north-east and we wondered if they would scuttle our efforts. I blindly shot and found the comet, C/2020 F3 (NEOWISE) just above the cloud band. Yes!

Viewed it in the binoculars (cheapo Bushnells) and we were able to tag it naked eye (when blocking the silly bright, badly aimed street lights). Star-like core. Tail fanning upward, nearly vertical. Rhonda's first.

Canon 40D, tripod-mounted, RAW mode. Shot in tungsten white balance; corrected to daylight. Pre-processing in DPP.

comet C/2020 F3 over Bradford

4:18. Wide-field, 18-55 Canon kit lens at 18, ISO 1000, f/8, 30 seconds, auto-focused (then set to manual), 10 second timer. Dark-subtracted with GIMP.

Auriga, the comet, Venus. [ed: I was thrilled to discover the Pleiades in the shot! Did not know at the time it was included.]

Stoopid light pollution!

4:28. Rhonda saw it directly, I caught it out of the corner of my eye, and flicked over to see the end. A bright, fast, short meteor burnt up north-bound (an Aquarid). It left a smoke trail that persisted for many seconds. Freebie!

comet C/2020 F3 in the dawn sky

4:51. Long lens, Vivitar Series 1 zoom at about 100mm, f/16, 2 seconds, manually focused, 2 second timer.

Sunday, July 05, 2020

found the triangle (Bradford)

It occurred to me that the Moon would be between Jupiter and Saturn tonight. The planetarium app confirmed that. Oh. A near triangle, with the Moon below the ecliptic.

Jupiter and the Moon started poking through the big tree in the south-east corner of the yard but the ringed planet we could not tagged.

Out on the street, we were able to take in all three. A nearly perfect isosceles triangle.

All were very orange.

lights in the sky (Bradford)

From the porch we watched the sky darken, saw the bat start its orbits, warded off persistent mosquitoes, and watched the stars slowly appear.

Rhonda noted a bright star, high up, in the east. Vega, no doubt.

Took me a while to clue in that I was seeing the pincer stars of Scorpius, Graffias and Dschubba. Later, squinting, I think I tagged the third member, below. Antares bobbed and weaved behind the nut tree.

Once I figured out the scorpion constellation, I realised the two obvious stars to the right were of my constellation, Libra. The phone app reminded me that Zubenelgenubi is not the lucida; that trait applies to Zubenelschemali, the upper star.

Later, I could see the bottom stars of Ophiuchus.

And we were visited by an inquisitive firefly! Yeh, apropos on International Firefly Day weekend!

Saturn, Jupiter, and Moon (Bradford)

Popped outside to close up things, batten down for the night, tidy, drop the umbrella... Spotted the bright Moon. Ugh. Oh. And two planets. Jupiter and Saturn. Moon was 150% of the J-S separation, to the west of Jupiter. It'd be really something if the Moon was actually the J-S split but I didn't think that would work, this time, in the northern hemisphere.

Saturday, July 04, 2020

how did we get so lumpy?

I don't know how I missed this before, the article over at the NASA Goddard Space Flight Center for science teachers (last edited in 2012). It's entitled The Lumpy Universe and asks the big question: how did the Universe go from so smooth to now very lumpy? Perhaps it is due to the small variations discovered in the cosmic background radiation, first with the COBE satellite and then with the WMAP probe.

helped backstage

Helped backstage with the DDO speakers night presentation on exoplanets by Emily Deibert.

Thursday, July 02, 2020

posted July 2020 doubles

Sent out my double star "bulletin" for July 2020. It is a short list of suggested targets. I shared this on the RASC Toronto Centre forums. And I post here for everyone.


I hope you enjoy my periodic posts with interesting and fun double stars. I think they are impressive, colourful, and beautiful. I particularly like how they punch through light pollution.

Here's a short selection from my life list. I did not include terribly tight or faint targets.

staralso known asalternate catalogue(s)
HD 106799 CamΣ1625 (Struve)SAO 2009, HIP 59836
HD 150340 HerSTF 2079 (Struve)SAO 84521, HIP 81575
1 BooSTF 1772SAO 82942, HIP 66727
HR 5568 LibH N 28 and 33 LibSAO 183040, HIP 73184
HR 6681 Ser (Cauda)HJ 2814 or HD 163336SAO 160915, HIP 87813

Please consider adding doubles to your observing list. Often they are easy. Occasionally they present some challenges and might require repeat viewing.

I look forward to hearing how you did. Holler if you have any questions.

Blake Nancarrow
astronomy at computer-ease dot com

Wednesday, July 01, 2020

cut and sanded

Once again, with Rhonda's awesome 20-inch double parallel-link arm scroll saw, I did more cuttting for the Dobsonian base project. (Continuing from work in May.) Printed my Visio diagram for notes.

Cut the semi-circles in the box side panels. Cut the handle in the box back panel. Cut the pieces away from the ground plate to form the legs. Cut the azimuth bearing in half. Cut the various reinforcement pieces for the box and cradle.

Used the surform to do a bit of shaping.

Fired up the new random orbit sander with 80 grit and had a go at most of the cut surfaces. Spent a bunch of time on the bearings to get rid of irregularities and make them uniform.

Dob base bits

Not shown: counter-top material from Clay. Neither did I grab the wood glue bottle.

A good Canada Day project, on a lovely day.

Wow. I think I'm ready to assemble...


Hockey pucks! Still need 3 of those!

It did occur to me that I'm not sure I picked up enough furniture glides. I bought a 4-pack and that will serve the altitude bearings. But I need three more for the base-ground plate.

And I also need to figure out the box-ground plate bearing.