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[collinsmark]

The simple response is "do a better job polar aligning", but given my alignment procedure, I expect (assume!) polar alignment to be within a couple of arcmin.

Any ideas?

Okay, I see now that there may be bigger issues, possibly in addition to seeing. What mount are you using?

But I don't think we can completely rule out seeing just yet, since seeing alone can cause the apparent position of an object to jump from one place to another as a larger blob of cold atmosphere passes into or leaves the direct line of site of the object. Think of atmospheric layers like ocean waves. Sometimes there are lots of small, turbulent regions, and sometimes, on top of that, there are larger, steady waves that have the effect of shifting things back and forth every few seconds or so.

But let's save this one for later. There may be bigger onions to peel.

------------------

But the present, top-layer of the onion doesn't look to me like polar alignment either. I would instead look to tracking issues with your mount, or vibrational modes of your mount (see below).

The thing about polar alignment is, if you do the mathematics behind it, you'll find that polar alignment errors manifest exclusively as declination drift. In order for polar alignment to significantly affect right ascension, the polar alignment would have to be so far off as to have the mount's pole pointed to the wrong side of the sky.

And both altitude errors and azimuth errors both manifest as declination drift. It's even possible for one to cancel the other out at certain patches of sky, only to have them constructively attack you as huge declination drift at other patches. But never do they have much effect on right ascension.

So if your drift is primarily on the right ascension axis, I'd put polar alignment on the backburner for now. The big problems are probably from somewhere else.

--------------------

Tracking issues. This is a whole bag of onions here, but let's start with the lowest hanging onion. Balance.

Ensure your scope is balanced, complete with everything on your scope as it would be when imaging. Imbalance causes the tracking motor to work harder, and can cause inconsistencies in the tracking accuracy. Think of the starter motor of an old jalopy trying to "turn over" the engine: rather than rotating the engine at a uniform rate, the engine turns in surges and spurts.

[Edit: also, flexure can cause drift in both the declination and right ascension axes. This can happen even if the polar alignment is good. Having a scope that is properly balanced in both right ascension and declination axes can alleviate this somewhat. While precise balance might not eliminate it completely, it helps a lot. By that I mean drift due to mechanical flexure can be pretty bad if the scope is not balanced well.]

As an anecdote, I used to balance my scope meticulously on the night of imaging, before sunset was over. Then I would take off the objective cap and put on the dew shield. And blam: tracking issues that caused multiple images along the right ascension axis (the same as what you show in your first image of your last post). That's because I didn't balance my scope with the dew shield on. Make sure you balance your setup in exactly the same configuration that it will be in when imaging. (E.g., don't adjust your balance with your lens cap on, since you won't have the lens cap on when imaging.)

Periodic error correction (PEC): if your mount supports PEC, consider using it.

Cable management: Don't have a bunch of cables dangling off the very end of the camera, down to the ground. This is where they are most susceptible to negative influence of angular moment on the system, if a breeze or wind is present. Try to tie any cables back such that they come back to the center of the system before running to the ground or elsewhere.

The same can be said for dew heater cables and whatnot. Don't leave them dangling. Try to run all cables to a central location on the system, such that if any cable does get perturbed, it doesn't exert much angular leverage.

----------------------

All systems have some wobble, and that wobble is more pronounced on some axes than others. Do you best to reduce the moment of inertia along all axes. [Edit: while maintaining balance, of course.]

Beyond that, there is the advice given in this forum in the advice to newcomers buying a first telescope (in a sticky post): Don't neglect the importance of the mount. If you have a set amount of money, don't spend most of it on the telescope (optical tube assembly), rather buy a quality mount.

 

[Devin-M]

Since you’re using a camera lens you can use a macro focusing rail (like the one I use shown below) to move the camera forward or backward to get it balanced on the declination axis.

https://www.adorama.com/mcfrss.html

 

[Andy Resnick]

How are you triggering the camera?

Are you aiming right at Polaris?

Thanks for the ideas!

Camera is triggered automatically, using the built-in intervalometer and 3-second shutter delay.

I polar align using this reticle:

https://www.primalucelab.com/media/...andy_cannocchiale_polare_GM8_G11_reticolo.jpg

Which does account for the slightly off-axis location of Polaris. There is some uncertainty where the 'second star' goes because the markings are per decade (2020 is the main scribed line, 2030 is the one counter-clockwise), but in general I know I have fairly good alignment b/c I can easily check as the night goes on.

 

[Devin-M]

Does the reticle account for the time of day?

 

[Andy Resnick]

Okay, I see now that there may be bigger issues, possibly in addition to seeing. What mount are you using?

But I don't think we can completely rule out seeing just yet, since seeing alone can cause the apparent position of an object to jump from one place to another as a larger blob of cold atmosphere passes into or leaves the direct line of site of the object. Think of atmospheric layers like ocean waves. Sometimes there are lots of small, turbulent regions, and sometimes, on top of that, there are larger, steady waves that have the effect of shifting things back and forth every few seconds or so.

But let's save this one for later. There may be bigger onions to peel.

------------------

But the present, top-layer of the onion doesn't look to me like polar alignment either. I would instead look to tracking issues with your mount, or vibrational modes of your mount (see below).

The thing about polar alignment is, if you do the mathematics behind it, you'll find that polar alignment errors manifest exclusively as declination drift. In order for polar alignment to significantly affect right ascension, the polar alignment would have to be so far off as to have the mount's pole pointed to the wrong side of the sky.

And both altitude errors and azimuth errors both manifest as declination drift. It's even possible for one to cancel the other out at certain patches of sky, only to have them constructively attack you as huge declination drift at other patches. But never do they have much effect on right ascension.

So if your drift is primarily on the right ascension axis, I'd put polar alignment on the backburner for now. The big problems are probably from somewhere else.

--------------------

Tracking issues. This is a whole bag of onions here, but let's start with the lowest hanging onion. Balance.

Ensure your scope is balanced, complete with everything on your scope as it would be when imaging. Imbalance causes the tracking motor to work harder, and can cause inconsistencies in the tracking accuracy. Think of the starter motor of an old jalopy trying to "turn over" the engine: rather than rotating the engine at a uniform rate, the engine turns in surges and spurts.

[Edit: also, flexure can cause drift in both the declination and right ascension axes. This can happen even if the polar alignment is good. Having a scope that is properly balanced in both right ascension and declination axes can alleviate this somewhat. While precise balance might not eliminate it completely, it helps a lot. By that I mean drift due to mechanical flexure can be pretty bad if the scope is not balanced well.]

As an anecdote, I used to balance my scope meticulously on the night of imaging, before sunset was over. Then I would take off the objective cap and put on the dew shield. And blam: tracking issues that caused multiple images along the right ascension axis (the same as what you show in your first image of your last post). That's because I didn't balance my scope with the dew shield on. Make sure you balance your setup in exactly the same configuration that it will be in when imaging.

Periodic error correction (PEC): if your mount supports PEC, consider using it.

Cable management: Don't have a bunch of cables dangling off the very end of the camera, down to the ground. This is where they are most susceptible to negative influence of angular moment on the system, if a breeze or wind is present. Try to tie any cables back such that they come back to the center of the system before running to the ground or elsewhere.

The same can be said for dew heater cables and whatnot. Don't leave them dangling. Try to run all cables to a central location on the system, such that if any cable does get perturbed, it doesn't exert much angular leverage.

----------------------

All systems have some wobble, and that wobble is more pronounced on some axes than others. Do you best to reduce the moment of inertia along all axes. [Edit: while maintaining balance, of course.]

Beyond that, there is the advice given in this forum in the advice to newcomers buying a first telescope (in a sticky post): Don't neglect the importance of the mount. If you have a set amount of money, don't spend most of it on the telescope (optical tube assembly), rather buy a quality mount.

Wow- thanks! There's a lot here for me to think about. To answer your questions:

1) I am using a Losmandy GM-8 mount, a German equatorial mount.

2) Balancing is pretty easy... Ohh... wait a minute- when I switched to 800mm (adding the 2x teleconverter) I didn't adjust the counterweight, so the mount is currently balanced in DEC but not RA...! Doh!

3) I have no dangling cables or dew shields or anything like that- just the lens and camera, the camera triggered by the internal intervalometer. Easy peasy.

4) PEC. I've tried it, don't really have the skill yet- too jittery with the controls.

Awesome! I have something new to try- many thanks! I'll have some questions about 'meridian flip' soon :)

 

[Andy Resnick]

Does the reticle account for the time of day?

Yes, the entire reticle rotates to permit proper alignment.

 

[Devin-M]

This is the procedure I use starting at about 5:26…

 

[Devin-M]

Another tip: do the precise polar alignment after putting the camera on the mount because if you align before adding the camera, the added weight of the camera can make the mount flex and take it out of alignment. So if you did it the way the guy in the video did without the camera on it won’t work very well.

 

[Devin-M]

Ohh... wait a minute- when I switched to 800mm (adding the 2x teleconverter) I didn't adjust the counterweight, so the mount is currently balanced in DEC but not RA...! Doh!

The teleconverter can take it out of balance in both DEC and RA because it adjusts the weight of the whole camera (affecting the RA) but it also moves the center of gravity away from the lens’s mounting hole (affecting the DEC). Take the camera + lens + teleconverter off the mount and put a pencil on its side on the floor and under the lens’s mounting hole (pencil on its side perpendicular to the lens) and see if its actually in balance at the mounting hole like a see saw. If not you may need the macro focusing rail to move the center of gravity relative to the mounting hole on the bottom of the macro focusing rail.

 

[Devin-M]

The Earth & Moon in a single photo...

"On October 13, 2022, NASA’s Lucy spacecraft captured this image of the Earth and the Moon from a distance of 890,000 miles (1.4 million km). The image was taken as part of an instrument calibration sequence as the spacecraft approached Earth for its first of three Earth gravity assists."

https://www.nasa.gov/image-feature/... -captures-earth-moon-ahead-of-gravity-assist

 

[Andy Resnick]

Another excellent weekend, I had three chances to try out the various suggestions. Unfortunately, I have mixed results. To be fair, I've also noticed that over time, I have been setting more and more stringent requirements on the images I retain for stacking.

The two main things I tried this weekend were: better alignment and better mount balancing. Again, here's my starting point- a stack of consecutive images (@400%) showing oscillatory behavior in right ascension (RA, vertical) and drift in both declination (DEC, horizontal) and RA:

At 400%, these RA oscillations are around 250 pixels, corresponding to 1.6 arcmin actual angular motion. Not sure if that's within spec.

One of the challenges is the lack of a meaningful user guide for the GoTo drive. The drive does output some useful metrics- I get live updates for 'mount balancing' and 'alignment model parameters'. If you check out those sites, you will note the relative lack of useful information- those URLs are the Gemini manual.

Mount balancing:
The GM8 user guide is pretty clear about the mount balancing procedure- mount the scope and adjust the position of either the telescope on the sliding dovetail (for DEC) or the counterweight (RA) until the mount holds a static position.

One clue I have about the possible underlying problem is while I have to position the telescope dovetail accurately to within 1 mm for DEC balancing, I can slide the counterweights within a 2-inch range of travel and the mount still stays (apparently) balanced. That is, the DEC axis rotates very freely but the RA axis seems 'resistive'. It's worth mentioning that the GM8 manual suggests leaving the mount slightly unbalanced... "This is done so that the worm gear is pushing against the slight load", resulting in improved tracking.

Looking at the GoTo drive output, the numbers have been very resistant to change- the 'Y' balance (DEC) stays at a constant 6% and a -2 offset, while the RA ('X' balance) rapidly oscillates between 6%-10% (poor hard-working jalopy motor!) and with the same -2 or -3 offset. Those numbers don't change, regardless of how well (or intentionally poorly) I balance the mount. I do understand what the PWM % numbers mean but have no clue what the 'offset' means- and I believe the important readout quantity is 'offset' which should be close to 0.

So on different nights, I moved the counterweights to different positions to see if there was any observable effect, first is with the counterweight too close to the mount (telescope heavy) and the other with the counterweight too far from the mount (counterweights heavy):

No substantive difference, the oscillations in RA are the same magnitude- 250 pixels (plus or minus). The reduction in DEC drift is discussed below...

One possible cause of the RA oscillations would be friction (somewhere) in the RA drivetrain, I think it's called 'stiction'. Although I store it with a dust cover, some of the gearing mechanisms may need to be cleaned after 10 years of use, but I'm not sure which. I've taken the thing apart before, so maybe I have a project...

Mount alignment:
One thing I tried did (minimally) impact the RA oscillation amplitude: better alignment. After I aligned to the same few stars 3 or 4 times, the model fully populated its parameters and the mount balancing changed- the DEC PWM was reduced to around 2% and the offset was 1, the RA PWM was still bouncing between 6-10% but the offset was also around 1. Here's what resulted:

These RA oscillations are around 200 pixels, which is better. Also, the RA drift is gone. Now, I'm not sure why (electronic) improved alignment impacts (mechanical) balancing, but that's what the drive output indicated.

Anyhoo... here's an updated image with Neptune and Triton:

 

[Andy Resnick]

The teleconverter can take it out of balance in both DEC and RA because it adjusts the weight of the whole camera (affecting the RA) but it also moves the center of gravity away from the lens’s mounting hole (affecting the DEC). Take the camera + lens + teleconverter off the mount and put a pencil on its side on the floor and under the lens’s mounting hole (pencil on its side perpendicular to the lens) and see if its actually in balance at the mounting hole like a see saw. If not you may need the macro focusing rail to move the center of gravity relative to the mounting hole on the bottom of the macro focusing rail.

Thanks for the suggestion- the lens is mounted to a dovetail that mates to the GM8 and by sliding the dovetail back and forth, I achieve DEC balance. Since I have to do this every night I image, adding or removing the tele is always accounted for.

 

[Andy Resnick]

Problem solved!

Before opening up the mount- a potentially risky step- I looked around on other discussion boards (e.g. cloudynights.com) for discussions about similar tracking issues and based on what I found, I realized I still hadn't done all of the basic check-out steps. Specifically, I didn't measure the periodicity of the RA oscillations to identify the 'defective part'.

When I did, I found the periodicity is exactly equal to the period of the worm drive: 8 minutes. This means that the RA oscillations are purely due to 'periodic error', although there could be additional low-amplitude higher order frequency components present in the error signal. So last night I carefully contorted myself and performed 2 rounds of manual guided PEC (periodic error correction), with pretty good results- I am now retaining close to 30% of my images, up from 10%. And, since the 'best' images are significantly improved as well, the overall stacked image quality is now doubly-improved. A few more PEC rounds should really clean up the tracking.

I also tightened the clutches as much as possible, but given how well I have been balancing everything, that didn't make mush of a difference.

Woot! Thanks to everyone for their suggestions!

 

[DennisN]

with pretty good results- I am now retaining close to 30% of my images, up from 10%. And, since the 'best' images are significantly improved as well, the overall stacked image quality is now doubly-improved. A few more PEC rounds should really clean up the tracking.

Congratulations!

 

[Devin-M]

Have you considered tracking with a small guide scope/camera & maybe something like an ASIAir Pro?

 

[Andy Resnick]

Have you considered tracking with a small guide scope/camera & maybe something like an ASIAir Pro?

I have considered a few models a while ago (Orion makes some nice ones, for example) and rejected the idea for a few reasons, for example:

1) Increased complexity. For example, I don't want to set up a computer every time I go image.
2) No obvious way to mount a tracking scope on my setup without re-engineering the saddle plate and dovetail

 

[Devin-M]

I have considered a few models a while ago (Orion makes some nice ones, for example) and rejected the idea for a few reasons, for example:

1) Increased complexity. For example, I don't want to set up a computer every time I go image.
2) No obvious way to mount a tracking scope on my setup without re-engineering the saddle plate and dovetail

1) The ASIAir Pro lets you control the autoguiding and targeting from your phone without a laptop

2) Here’s an idea… I did this with a macro focusing rail (imagine a small guiding scope instead of the laser pointer)

(I used one macro focusing rail to move the camera’s center of mass to balance the declination axis with the 2x teleconverter on, and a second macro focusing rail under the 1st to side mount the laser pointer or alternately a guide scope.)

https://www.adorama.com/mcfrss.html

 

[bruha]

2.11. I made some pictures with my small telescope (Newton 600 x 100 mm) with eyepiece camera bresser from window (bad light condition of course furthemore already cca half moon was present)... last four images are Gimp corrected...

 

[collinsmark]

IC 5146, The Cocoon Nebula (also called Caldwell 19, SH 2-125, and Barnard 168), captured from my back patio in late September-October, 2022.

Have you been lying low lately, gathering your strength, perhaps undergoing a process of metamorphosis (so to speak), knowing soon you'll spring forth as a beautiful butterfly? If so, then the IC 5146 may be just the nebula for you.

The Cocoon Nebula lies in the constellation Cygnus (the swan) and is about 3300 light-years away (sources differ slightly on the distance).

Equipment:
Meade 10" LX200-ACF fork mounted on an equatorial wedge.
Starlight Instruments FTF2008BCR focuser modified for electronic focusing.
Off-axis guider (OAG) with ZWO ASI174MM-mini guide camera.
Baader 3.5-4 nm Ultra-Narrowband filter set.
ZWO ASI6200MM-Pro main camera.

Software:
Nighttime Imaging "N" Astronomy (N.I.N.A.)
PHD2 guiding (of course)
PixInsight
Topaz Labs Denoise AI
Topaz Labs Sharpen AI

Integration:
Bortle class 7 (maybe 8) skies
All subframes binned 3×3
SII: 71×10 min = 11.83 hrs
Hα: 76×10 min = 12.66 hrs
Oiii: 74×10 min = 12.33 hrs
Total integration time: 36.83 hours

 

[Andy Resnick]

The moon, Jupiter, and 22° halo:

Shot @ 15/4, 30s ISO 64. Image cropped but otherwise straight-from-camera jpg.

 

[bruha]

Hi, here is two images of three sunspots as I catch them 8.11.-image 1 is by SV Ebony camera 1.25"
and image 2 is by Bresser full HD deep sky camera 1.25" -with green filter both
lot of succes

 

[Andy Resnick]

In a strange, inverted, turn of events, I had to wait until there was a break in the clear nights to catch up :)

This time of year I can image 4 planets each night- First, Neptune (and Triton) (50% downscaled):

Jupiter and 4 Galilean moons (composite, 100%):

Mars (100%)- nothing amazing, but whatevs:

and Uranus (with 2 moons, not sure which... maybe Umbriel and Titania), 100%:

 

[collinsmark]

NGC 7822 captured from my back patio in October, 2022.

The portion of NGC 7822, as shown here, is part of a larger nebula commonly called "The Question Mark Nebula," that resembles a giant question mark ("?"). You can't see the question mark here because the image is "zoomed in" too much, so to speak. The image here is only the central region of the nebula.

It was difficult for me to process this image simply because there's so much going on in this region of space. I kept getting lost.

Equipment:
Meade 10" LX200-ACF fork mounted on an equatorial wedge.
Starlight Instruments FTF2008BCR focuser modified for electronic focusing.
Off-axis guider (OAG) with ZWO ASI174MM-mini guide camera.
Baader 3.5-4 nm Ultra-Narrowband filter set.
ZWO ASI6200MM-Pro main camera.

Software:
Nighttime Imaging "N" Astronomy (N.I.N.A.)
PHD2 guiding (of course)
PixInsight
Topaz Labs Denoise AI
Topaz Labs Sharpen AI

Integration:
Bortle class 7 (maybe 8 ) skies
All subframes binned 3×3
SHO mapping
SII: 75×10 min = 12.5 hrs
Hα: 81×10 min = 13.5 hrs
Oiii: 63×10 min = 10.5 hrs
Total integration time: 36.5 hours

 

[DennisN]

NGC 7822 captured from my back patio in October, 2022.

Simply gorgeous! The colors and details are stunning!
And there's a lot going on in the image, many different things to look at!

 

[DennisN]

Astrophotography accessories

Here's a report on some accessories for astrophotography with system cameras. Some of you may already have sufficient/equivalent gear but I wanted to share these things since it may give some ideas to someone .

Star Focusing Mask (homebuilt)

An upgraded and even lighter version (previous version here) of a homebuilt star focusing mask which is made of a perforated plastic screen on a cardboard frame:

I've fastened a small piece of sleeping mat to it, so I can just quickly hang it on any of my lenses:

I wanted to report that I've tested it "in the field", and this solution works well with real stars, and actually better than I personally expected .SmallRig (various gear)

SmallRig (https://www.smallrig.com/, also available on Amazon) is a clever solution for mounting a large variety of accessories to a camera. The SmallRig accessories I show below are all made from aluminium alloy and they are quite lightweight and not too pricey, in my opinion.

I'm quite impressed and satisfied with the system.

For me it solved the following tasks for astrophotography:

• Lens support for longer/heavier lenses
• A way to attach a motorized focusing mechanism (which I've planned building)
• Live guiding possible with smartphone attached (an idea I got)

The system can of course be used for other non-astro things, e.g. attaching external lights and microphones to the gear.

1. You start with a cage which fits your particular camera:
(the cage has a large number of 1/4 inch and 3/8 inch threaded holes which let you attach other gear to the cage)

SmallRig cage with Sony A6000 mounted:

2. Then you can mount various things to the cage...

SmallRig Baseplate attached to the cage:

Two aluminium rods attached to the baseplate:
(on these rods I can attach other gear for the lenses themselves)

A movable clamp attached to the rods:
(on this one I will mount my planned motorized focusing mechanism)

A movable lens support for long/heavy lenses attached to the rods:

A smartphone holder which can be rotated left/right and forwards/backwards...

...which allows the smartphone to be rotated* to be directed at the eyes even though the camera is pointing upwards at a small angle...

...or a large angle (almost straight upwards here, and with the Android astronomy app SkEye running on the phone):

* The app SkEye can be calibrated ("Indirect mode" -> "Alignment") so it shows what the camera in the cage is pointing at (when the smartphone has been rotated with respect to the camera in the cage).

It works exactly like I thought and with this solution you get live guiding to targets in the night sky :

Sony A6000 in a SmallRig cage with a smartphone mounted and running SkEye:


You can also zoom in on the app to show a more magnified portion of the night sky.

It's not full GoTo of course, but I think it's very useful for me, at least. I have not tested it "in the field" yet, but I expect it to work as I thought. I think it will make it much easier to find targets in the night sky .

 

[bruha]

Hi, Saturn and Jupiter with 3 moons made by Newton 1000x200 mm and eyepiece camera SV EBONY
on Saturday , South Bohemia (countryside but with light pollution cca Bortle 6. im. with ---g are Gimp corrected. (I was not able more decreased Saturn exposition in order to see belts... )
Lot of succes

 

[Andy Resnick]

It's been cloudy for a week and there's another week to go, so this is as far as I go for the year with M31 (Andromeda galaxy):

M31 just barely fits in the frame @800mm (35mm image format). The image is still a little too noisy, I need another pass or two to get sufficient integration time.

deets: 800/8 (100mm refractor) Nikkor and Nikon D810 on Losmandy GM-8, 14 very-hard-won hours :) @10s subs. APP for stacking.

 

[DennisN]

so this is as far as I go for the year with M31 (Andromeda galaxy):

Gorgeous!

 

[berkeman]

It's been cloudy for a week and there's another week to go, so this is as far as I go for the year with M31 (Andromeda galaxy):

Beautiful. May I download that to use as my background on my phone and laptop?

 

[bruha]

Beautiful !
Can I ask what is mygnifying of this image?

 

[Andy Resnick]

Beautiful. May I download that to use as my background on my phone and laptop?

Thanks! Certainly! (thanks for asking first :) )

 

[Andy Resnick]

Beautiful !
Can I ask what is mygnifying of this image?

Thanks!

Regarding magnification, 800mm provides about 16X magnification, using the convention that a 50mm lens is matched to the field of view of a naked eye.

 

[bruha]

Thank you

 

[bruha]

Made by my friend (half professional photographer)':

The brightest star is Deneb from the constellation Cygnus, and to the left of it the Pelican Nebula and North America can be seen.
...
Technique: Sony A7, Samyang 135/2, SW Star Adventurer, UHC Astronomik filter
Exposure: 150x40sec
Post-processing: AstroPixelProcessor, PixInsight, Photoshop

 

[collinsmark]

NGC 281, the Pac-Man Nebula, captured from my back patio from late Oct through the first part of Nov, 2022. The nebula is found in the constellation Cassiopeia, and is about 9,200-9,500 light-years away (sources vary).

Its common name is the "Pac-Man" nebula, presumably due to the fact that, at a glance, it sort of looks like the 1980 video arcade game character, "Pac-Man." (Tilt you head and blur your eyes, if it helps.)

It obviously wasn't always called the "Pac-Man" nebula; it was discovered by American astronomer Edward Emerson Barnard (most famous for Barnard's Star, the star with the highest proper motion in the night sky) in 1883. It just goes to show that the common names of astronomical objects are not set in stone, and can evolve over time. (Edit: Even today, the nebula is frequently called "Pacman," without the hyphen.)

Looking at NGC 281 in more detail, there are features within the nebulosity that the brain might interpret as facial features, such as a human eye (upper-center), and maybe an ear. Also a mouth & chin, perhaps? Cheekbones?

Equipment:
Meade 10" LX200-ACF fork mounted on an equatorial wedge.
Starlight Instruments FTF2008BCR focuser modified for electronic focusing.
Off-axis guider (OAG) with ZWO ASI174MM-mini guide camera.
Baader 3.5-4 nm Ultra-Narrowband filter set.
ZWO ASI6200MM-Pro main camera.

In the 1980 video game, Pac-Man was chased by ghosts.

Software:
Nighttime Imaging "N" Astronomy (N.I.N.A.)
PHD2 guiding (of course)
PixInsight
Topaz Labs Sharpen AI

My back patio is called the Shady Crypt Observatory.

Integration:
Bortle class 7 (maybe 8 ) skies
All subframes binned 3×3
SHO mapping
SII: 78×10 min = 13.0 hrs
Hα: 75×10 min = 12.5 hrs
Oiii: 67×10 min = 11.17 hrs
Total integration time: 36.67 hours