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Starting out in EAA, hello from the UK! Camera advice requested.

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23 replies to this topic

#1 Rammysherriff

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Posted 19 September 2023 - 03:56 AM

Hello everyone from the rainy UK!

 

I'm no stranger to astrophotography, and ended up 10 years ago with a guided set up, cooled CCD camera, narrowband imaging and whatnot. I sold all my gear  as it wasn't getting used often enough - the British weather, and a demanding job with early starts were my enemies. I used to spend a lot of time on Cloudy Nights back then, and it's good to see the community is as busy and helpful as ever.

 

10 years on, I am retired, recently married, and we spend a lot of our time now touring the UK in our caravan (trailer); we've been out under some good dark skies, and I wondered about a scope again. I spotted a previously owned Celestron C6 f10 SCT on an Advanced GT mount for a good price, as I reckon it's not too big to manage as we travel. I got permission from the Financial Controller to buy, so off we go!

 

Initial intentions were to focus on:

 

  1. Visual observing, lunar solar and planetary, plus brighter DSOs.
  2. Piggyback my DSLR on top for some longer exposure widefield imaging.

 

However, I started reading about EAA, and it interests me as if offers a better experience IMHO than visual observing, especially if I am viewing with the Mrs. 

 

So.... I am looking for some camera advice please, if I can sketch out my plan? I am trying to keep setting up  and complexity as low as practical, as it won't be a permanent setup just yet.

 

  • I would like to be able to EAA on the lunar, solar and planetary targets
  • I would also like to be able to do EAA on some DSOs
  • I would prefer an uncooled camera/passively cooled camera
  • I prefer colour over a mono camera
  • I don't want to start adding extra scopes or changing scopes at this time, so will image through the C6
  • I don't want to try guiding at this point

 

I have a modern laptop with a 1080p screen, and am happy to be sat outside pressing buttons etc, so I'm not investigating any remote viewing and control options.

 

  1. I have considered the ZWO ASI662MC which is well within my budget, and seems to be able to do it all; am I right?
  2. What are the pros and cons of using a 4K 8.3 Mp camera such as the ZWO ASI 678MC USB3.0? I know viewed 'live' on my laptop screen it won't make any difference, but my home PC screen is 4K if I am messing around with any captured images.
  3. I see you can EAA through a DSLR, although this seems to be a slightly experimental area, and I'd only try this for DSOs (EDIT using the camera lens), not planetary. Is DSLR EAA a realistic option? (Canon 90D by the way)

 

 

So, are my assumptions correct or not, and am I heading in the right direction folks? Thanks in advance as always.

 

 

    Simon


Edited by Rammysherriff, 19 September 2023 - 09:10 AM.

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#2 Darth Riker

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Posted 19 September 2023 - 07:18 AM

Did you happen to come across these articles? Might be of some help:
 
https://astroforumsp...mc-vs-asi662mc/

https://astroforumsp...trophotography/


Just for reference - the product page links for both cameras:
https://astronomy-im...duct/asi-662mc/

https://astronomy-im...oduct/asi678mc/


Edited by Darth Riker, 19 September 2023 - 07:20 AM.

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#3 Rammysherriff

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Posted 19 September 2023 - 07:58 AM

Did you happen to come across these articles? Might be of some help:
 
SNIP

No I hadn't spotted those, but at first glance they look very useful, thank you very much.



#4 rapture91

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Posted 19 September 2023 - 08:25 AM

If you want to do EAA with either the 662MC or 678MC, you might want to look at a 0.63x focal reducer in order to widen your field of view.

These sensors are rather small in combination with a 1500 mm focal length (at f/10).

I‘m using a 10“ f/5 dob (1250 mm focal length) reduced to 938 mm in combination with the 533MC, which has a 1“ sensor. This way I‘m able to frame most DSOs with a few exceptions. I also love the square sensor, which in the beginning seemed kinda unusual.

Planetary imaging also works with this camera, although it is a bit more expensive than your preferred options :)

Can‘t comment on the use of a DSLR for EAA, since I don‘t have any experience with that.


Good luck with your decision. I bet you‘ll enjoy doing EAA while touring the UK, have fun!

#5 Rammysherriff

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Posted 19 September 2023 - 09:03 AM

If you want to do EAA with either the 662MC or 678MC, you might want to look at a 0.63x focal reducer in order to widen your field of view.
 

Yes I was just pricing up the Celestron and the Antares alternative this morning, as the FOV of the scope is like a pencil! I also have in my box an ATIK 0.5 x reducer that goes onto thje 1.25" nosepiece which might get used, it seemed to work ok on my old ATIK camera.

 

Many thanks and clear skies!

 

EDIT: my wife has just returned from shopping, and she has bought me a genuine German bierstein with a lid from an antique shop. I will test it later. Prost!

 

ANOTHER EDIT: the ASI 553MC looks great, but I am trying to avoid a cooled camera because of expense, but also to avoid being tempted back into autoguiding and long exposure stuff. That can wait till we have a proper house and I can make an observatory :-)


Edited by Rammysherriff, 19 September 2023 - 09:26 AM.


#6 PeterC65

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Posted 19 September 2023 - 10:34 AM

I'm also in the UK and do both EAA and visual, EAA because you do get to see way more than with visual, but I still like to sit out under the stars and see things with my own eyes.

 

I'd recommend an IMX585 based camera, so the ASI585MC if you like ZWO products. I have the Player One version, the Uranus-C. Compared with the ASI662MC, the ASI585MC has the same sized pixels, just more of them (4K), on a sensor twice the size (so twice the field of view). The 585 will do everything the 662 will do, and more. You can turn it into a 662 by selecting a 1920x1080 region of interest for planetary imaging and use the full sensor for DSOs. I use mine with a 4K monitor during an EAA session and I find that useful as the image is superb and I can digitally zoom by at least x2 and still get a good image.

 

EAA is not a good way to observe the planets though as you can't stack images in real time so you're just looking at live video. The Moon can look OK with an IR pass filter (to reduce atmospheric wobble) but I much prefer to observe the planets and even the Moon visually (I find the Moon looks best with a binoviewer).

 

I've also used a DSLR for EAA, a Canon EOS 1100D with a shutter, and while it works, I don't think it's practical to have the shutter clicking away all evening. Used with a scope, a DSLR is quite a weight for the focuser and very cumbersome. I only use mine now when I want a really wide field of view, using the camera lenses rather than a scope.



#7 MarMax

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Posted 19 September 2023 - 11:37 AM

2x with Peter's advice above. You can't go wrong with a 585. I also agree that visual planetary (and Moon) observation is much more pleasing than with EAA. I don't know much about a C6 but with the C11 the /6.3 reducer is a must have item.

 

Since you have the laptop I'd recommend SharpCap 4.1. You can do everything you need via USB. Between this forum and the Celestron Computerized Telescopes forum you can find just about everything you need in the way of answers to questions.

 

EDITED to say that I keep thinking in terms of my C11 so some larger pixels may work better with the C6 (unless you are considering a Hyperstar). So also consider the uncooled 533 as mentioned by bmcclana below.


Edited by MarMax, 19 September 2023 - 12:11 PM.

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#8 bmcclana

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Posted 19 September 2023 - 11:52 AM

I would recommend either a 585 or 533 based camera.  Both ZWO and PlayerOne make uncooled versions of the 533.

 

I have a PlayerOne 533 Saturn-C and use it with all my scopes from 135mm to 2000mm and for all target types. 



#9 Rammysherriff

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Posted 20 September 2023 - 03:56 AM

PeterC65, MarMax, bmcclana: all very useful stuff, it has really helped me, and you have answered some questions I was getting ready to ask! 

 

The 585 isn't a massive jump in budget and still comes in under my rough limit of £500 if I get a focal reducer, this is good news! It does offer a bit more than the ASI 678. The uncooled 533 is interesting, especially the square sensor, but I think a 585 is the way to go as I think I prefer the conventional L x W ratio.

 

So:

 

  • the larger sensor will give a much better fov which will be very useful, this is a big plus
  • I now know I can shoot at lower resolutions if needs be - I had assumed this would be the case and would be useful if happy to work at 1980 x 1020 for live viewing on a 1080p screen out in the field
  • I now know EAA as we mean it here  isn't made for planetary stuff; it makes sense actually now I think about it - live stacking on DSOs etc  is to over come SNR, but planetary stacking is ditching the wobbly frames to overcome the seeing?
  • for clarity, I didn't want to hang a DSLR off the scope but piggy back it with camera lenses for widefield, just like you said Peter, and initially just rely on polar alignment

 

Other little thoughts are that with  some live frame captures and using Registax on the fly, I  can do an almost real time  planetary/lunar EAA session, so the Mrs can see the Clangers on the moon and so forth wink.gif

 

It has also occurred to me that with the piggyback DSLR, I could use the 585 to guide, but let's leave all that till I've actually bought it and used it a bit first!

 

Thank you everyone, I think my mind is 99% made up, and I don't think I have any questions left to ask.


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#10 PeterC65

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Posted 20 September 2023 - 04:53 AM

The uncooled 533 is interesting, especially the square sensor, but I think a 585 is the way to go as I think I prefer the conventional L x W ratio.

I considered an IMX533 sensor, but they are quite a bit more expensive than the IMX585, and any display on which you might view the image will be rectangular not square.

 

 

I now know EAA as we mean it here  isn't made for planetary stuff; it makes sense actually now I think about it - live stacking on DSOs etc  is to over come SNR, but planetary stacking is ditching the wobbly frames to overcome the seeing?

Yes that's correct. It is possible to stack Moon and planetary images, and to select the best frames (with the least wobble), but this is a slow process and can't be done in real time for EAA. The best software I have found for dong this (post processing) is AutoStakkert, followed by image sharpening with Topaz DeNoise, but that's AP, not EAA.

 

 

Other little thoughts are that with  some live frame captures and using Registax on the fly, I  can do an almost real time  planetary/lunar EAA session, so the Mrs can see the Clangers on the moon and so forth wink.gif

Observing the Moon using EAA can be almost as good as visual if you use an IR pass filter. I also switch on auto colour balance in SharpCap when I do this. You are observing live video so you get the sort of wobble that you see through an eyepiece, but that's OK. One big advantage I find with doing this is that I can observe the Moon on the 4K second monitor while having a Moon map open on the laptop allowing me to figure out what I'm looking at.

I wouldn't try to do the AP style processing on the night.

 

 

It has also occurred to me that with the piggyback DSLR, I could use the 585 to guide, but let's leave all that till I've actually bought it and used it a bit first!

You don't need to guide for EAA, and having a DSLR / its lens / a scope / a 585 camera all fitted to a mount would be a heavy load, so you'll need a meaty mount.



#11 Rammysherriff

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Posted 20 September 2023 - 05:38 AM

Peter,

 

again all very useful insights, and having travelled this road before - I started here in 2004 it seems! - I know it's always best to ask an expert before getting the wallet out. It's very kind of you to share your experiences and thoughts.

 

I used to Registax short video clips on the night for fun, but in those days it was a 640 x 480  Philips webcam; I guess a 1080p or even a 4K set of images will take commensurately longer to process, so may be just best viewing totally live like you say. Yes the IR pass filter rings a bell now, I'll put it on the list.

 

No, I don't want to overload the mount, it's just worth a try if I have all the kit to hand. If it's a balls up, then nothing lost. Plus - it gets my hand back in to using PHD or Guidedog or whatever the current fave autoguiding app is. Longer term, I plan to invest in a fast short apo scope, and I will build a side by side mount that will let me mount a DSLR or the apo, plus a guidescope, thereby reducing weight on the mount, and giving me the most imaging options from the minimum kit.

 

If I get chance to build a more permanent set up, a 4K screen will definitely be a part of the set up, to make the most of the camera, but that's going to depend on a lot of variables over the next 4-5 years on where and how we live :-) 


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#12 PeterC65

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Posted 20 September 2023 - 06:30 AM

I think Registax has had little development since you used it in 2004 so it is rather clunky. Some people still use it. I've tried using it but found the wavelet control values hard to get right. Tools like Topaz DeNoise are much simpler to use (just a couple of sliders to set) and do a really great job of sharpening up the whole image.

I still have a lot to learn myself about EAA, and astronomy in general, by the way!



#13 Rammysherriff

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Posted 20 September 2023 - 10:45 AM

Sure, I reckon I'll try alternative apps that are 'new' while I catch up on what has developed during my sabbatical. I've still got all my ImagesPlus CDs stored somewhere!



#14 alphatripleplus

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Posted 20 September 2023 - 10:55 AM

It you are interested in current tools and software used by planetary imagers, take a look at the major and minor planetary imaging forum. Captures taken of the planets in the EAA forum are limited mostly to single snapshots, as post-processing after capture is beyond the scope of this forum. Some members here have dabbled in single exposure snapshots for EAA, but you'll see they are limited compared to what can be done with the tools used by planetary imagers.


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#15 Tfer

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Posted 20 September 2023 - 11:30 AM

It you are interested in current tools and software used by planetary imagers, take a look at the major and minor planetary imaging forum. Captures taken of the planets in the EAA forum are limited mostly to single snapshots, as post-processing after capture is beyond the scope of this forum. Some members here have dabbled in single exposure snapshots for EAA, but you'll see they are limited compared to what can be done with the tools used by planetary imagers.

This forum specializes in Electronically Assisted Astronomy.

 

There’s nothing mentioned about having a pretty picture in the end.

 

I observe planets using cameras. I’m electronically assisted.  Anyone who believes they can view planets better with an eyepiece is deluded. It LOOKS clearer, because compared to a basic planetary camera at F10, it’s tiny, so the abberations in seeing quality aren’t as noticeable.  But they are still there; wiping out details. 

 

However, with a camera I have capabilities that go far beyond the human eye’s ability.

 

Mars for instance, is notoriously difficult to observe. The features on the planet are so low in contrast compared to the brilliancy of the disc, that it can take weeks or months to train your eyes to see them.

 

With a camera, I lower the gain and exposure times, and adjust the mid slider.  Those same features are clear obvious.

 

If I decide to process some video, that’s outside of the scope of EAA, but just looking at it?  A camera wins everytime over visual.

 

I might not have a picture in the end, but I didn’t see anything in the rules of EAA that requires one…
 


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#16 PeterC65

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Posted 21 September 2023 - 03:02 AM

I observe planets using cameras. I’m electronically assisted.  Anyone who believes they can view planets better with an eyepiece is deluded. It LOOKS clearer, because compared to a basic planetary camera at F10, it’s tiny, so the abberations in seeing quality aren’t as noticeable.  But they are still there; wiping out details. 

 

However, with a camera I have capabilities that go far beyond the human eye’s ability.

That's really not what I've found so I'm interested to understand what you do differently when observing the planets via EAA as I would like to be able to do so.

 

What scope and camera are you using?

 

For the planets, via EAA, I've mainly used a 150mm Newtonian and IMX585 camera. With that combination they appear small and more fuzzy than they do with an eyepiece. When I observe the planets visually I use a 127mm Mak. I've not yet tried the Mak with EAA as it's too slow for anything but the planets.



#17 Tfer

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Posted 21 September 2023 - 08:29 AM

That's really not what I've found so I'm interested to understand what you do differently when observing the planets via EAA as I would like to be able to do so.

 

What scope and camera are you using?

 

For the planets, via EAA, I've mainly used a 150mm Newtonian and IMX585 camera. With that combination they appear small and more fuzzy than they do with an eyepiece. When I observe the planets visually I use a 127mm Mak. I've not yet tried the Mak with EAA as it's too slow for anything but the planets.

I use my C11 at F10 and currently a 678MC camera.

 

Both the 585 and the 678 are low noise cameras, and very sensitive.  At F10, my focal length is 2800mm.  You didn’t mention the focal length of your reflector, but I’m guessing it probably an F6, giving a focal length 1/3 of mine at 900mm.  That’s why it’s smaller, but it shouldn’t be blurry a all.
 

This is a single frame of Jupiter from last week.  The ROI is 480X480 pixels.

Attached Thumbnails

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#18 Tfer

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Posted 21 September 2023 - 08:57 AM

The 585 sensor has 2.9 micron pixels. The 5X rule (focal length should be 5X the pixel size) states that you should be viewing at F14.5.

The reason I’ve gone to a 678 is the 2.0 micron pixel size is a perfect match for my scope at F10.

No Barlow required!
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#19 PeterC65

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Posted 21 September 2023 - 11:04 AM

I use my C11 at F10 and currently a 678MC camera.

You're scope has a much bigger aperture than any of mine which probably helps, but I take your point about the x5 rule and I realise that I should be using the 127mm Mak (F11.8) for observing the planets rather than the 150mm Newtonian (F5.0). It's on my list of things to try!



#20 Andy Lucy

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Posted 22 September 2023 - 09:53 AM

I have the ASI678mc and it’s very good as a planetary camera.  

 

I’ve tried using it for DSO imaging in combination with an Askar fma135 scope but the results are mixed.  It gives very good detail, as a result of the small 2 micron pixels, but all of my stacked images show colour defects:  excessive noise, and colour mottling in the darker areas.  I suspect that this is because the dark current is relatively high as the problem is worse on warmer evenings.  
 

The ASI585mc has significantly lower (about 1/10) dark current than the ASI678mc so should suffer much less from this problem.

 

Andy



#21 Mark Lovik

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Posted 22 September 2023 - 10:28 AM

I have the ASI678mc and it’s very good as a planetary camera.  

 

I’ve tried using it for DSO imaging in combination with an Askar fma135 scope but the results are mixed.  It gives very good detail, as a result of the small 2 micron pixels, but all of my stacked images show colour defects:  excessive noise, and colour mottling in the darker areas.  I suspect that this is because the dark current is relatively high as the problem is worse on warmer evenings.  
 

The ASI585mc has significantly lower (about 1/10) dark current than the ASI678mc so should suffer much less from this problem.

 

Andy

I have not used the '678 camera, but my '178mc camera is getting close to the pixel size.

The speed collecting images .. even at F/4.5 will be slow - so you need longer EAA integration times to see anything, and yes ... background noise becomes an issue

 

1. Background noise, color mottling -

  • often referred to as walking noise
  • is a common issue when you are pushing signal starved images. 
  • Make sure to dither with SharpCap (it works unguided)
  • longer total integration times usually helps

2. Poor image quality - image artifacts

  • just integrate longer on the signal
  • make sure to really bump up your gain settings (avoid a/d quantization artifacts)
  • pay careful attention to darks and flats

Edited by Mark Lovik, 22 September 2023 - 10:30 AM.

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#22 Andy Lucy

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Posted 22 September 2023 - 06:59 PM

 

1. Background noise, color mottling -

  • often referred to as walking noise
  • is a common issue when you are pushing signal starved images. 
  • Make sure to dither with SharpCap (it works unguided)
  • longer total integration times usually helps

2. Poor image quality - image artifacts

  • just integrate longer on the signal
  • make sure to really bump up your gain settings (avoid a/d quantization artifacts)
  • pay careful attention to darks and flats

 

Mark,

Thanks for the comments.  I’ve attached an image of M81 and M82, stretched to show the “colour mottling” problem with my ASI678mc more clearly.  Similar effects (same colours, similar places) are visible in other of my images.

  • it’s definitely not walking noise: in any case the subs were dithered
  • Integration time for an f/4.8 scope was ample (90 minutes)
  • gain setting was 200, so no quantisation problems
  • flats clearly aren’t the issue
  • The sensor temperature stayed at 4.1 - 4.8 C during acquisition but, not having a dark library at that temperature, I used the Pixinsight Dark Optimisation routine.

M81 and M82 integration_ABE_PCC_arcsinh_HT_downsampleX2.jpg

 

Andy



#23 Mark Lovik

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Posted 22 September 2023 - 08:18 PM

Normally I dither over 10 pixels and do it frequently enough to average over my EAA exposure interval.  You may want to play with your dithering to see if changing the dither conditions help.

 

The left over noise can be a reduced a bit with your stretch - it seems really tight.  Then be a bit more aggressive on setting your black level.  I normally need to play with these setting to get things visually clean.  I make sure that I have no enhancements set when I do this in SharpCap.

 

If you are running SharpCap 4.1 - if you get the image as clean as possible before setting any enhancements.  The 4.1 color filter (in enhancements) is great to reduce the background you are seeing.  In 4.1 the bi-linear filter does a respectable job doing the same thing.  The bi-linear filter can normally cleanup the background or background nebulosity without impacting the rest of the view.  It may take some playing around with the settings.

 

Another setting that can make a difference on this image is the color saturation level for the histogram.  I used to push this to make my colors pop -- over time I have dropped the saturation down - it's a personal preference - but it has a side effect of improving the color variations in my background artifacts. 

  • I had a tendency to used saturation to handle EAA views that seemed color poor. If you align the colors for the histogram and lower the aggressiveness of the stretch - the colors will tend to be more pronounced for the brighter features in the image. 
  • The aggressive stretch tends to saturate the color values - so colors blend to white.  I compensated with a higher color saturation - but this was not a great habit for me.
  • So pulling down the aggressive stretch, and pulling down the saturation together helps the image and the background.

 

I believe the raw image has enough data to keep the galaxies intact, and drastically improve the background level at the same time.



#24 Andy Lucy

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Posted 23 September 2023 - 02:07 PM

Mark,

I did state that the image I posted was stretched to show the mottling effect:  with a more normal stretch the effect is still there but - obviously - less visible.

 

I agree that the unsightly effects could be mitigated by playing around with black level, colour saturation, etc, but my efforts to do so compromise the image too much for my taste.

 

Artefacts like this do not occur when I use my asi2600MC camera - so it may be a reasonable assumption that it is a camera effect.  [You might suspect a temperature effect, but the problem in the above image occurred when the sensor was at a steady 4oC (ambient was -3oC)].  Also, I'm not the first person to report about colour mottling with the ASI678MC:  see https://www.cloudyni...8mc/?p=12675049

 

Personally, I won't be using my asi678MC any further for DSOs.  I've made a number of attempts to get good results with it and have not been satisfied with the outcome. It's a shame, because a camera with 2-micron pixels should pair very well with short focal length refractors.

 

Regards,

Andy




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