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First DSO edit, Affinity Photo / StarTools


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So another muppet that hasn't a clue really! Sorry in advance.

Not really looking for this to be a thread on how good/bad my images taken are as that's for another forum and how to use the hardware (camera, telescope, polar aligning, guiding, etc), but more how to get an image from DSLR to impressive image.

Image was of NorthAmerica Nebula, NGC7000, 120x1min lights, 60x1min darks. ISO200, f/4.9 at 500mm.
I've had a go with Startools and followed the suggested workflow on the website and was pleased with the output
My workflow obviously needs addressing, but I've used the following edits:

Import Tiff, Linear unstretched.
AutoDev, selecting ROI less couple of hundred pixels on each edge
Bin at 50%
Crop edges similar to ROI
Wipe (default settings)
FilmDev => digital 97%,Gamma0.75, RGB_L 100% each, WB UseStars (dark anomolies didn't appear to change much at this point)
Contrast => BASIC preset, Locality 75%, other settings left
HDR => Tame preset
Other panels not really touched or more that I didn't either know what I was doing or didn't like the result

Here's what I came up with and nebulosity is nicely visible but not a very impressive punchy image.

1359351439_ScreenShot2021-09-10at14_14_54.png.e8875a8fc25be3005d3e90ae80824c3d.png

Affinity obviously gave something completely different, where I concentrated a little more on the nebula but I'm sure most would agree that I haven't got a clue where to start!

APP.png.3b002875bb4e433419286d02eed60f42.png

I'd love folks to have a go at editing the raw in APP/Photoshop and summarise layer settings used - I've gone mainly with levels, curves, brightness and contrast and used about 15 adjustment layers all in all, which I think is going down the wrong route (especially as they're all the same type of adjustments!)
eg my first 5 layers are Brite&Contr, 100/0 100/0 50/0 0/100 0/80, then a contrast curve and astrostretch curve (arcsinh), then more of the same.
I'm really keen on getting into the edits, but there are clearly many filter/layer options I am unaware of, and how they work with the images.

It might be a bit of a cop-out by asking for how others would edit this specifically, but truthfully any help is appreciated on this!

Thanks so much in advance

 

DSS Stack Output.TIF

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1 hour ago, happy-kat said:

Have you plate solved your image.

@happy-kat, nope in short! Thought plate solving was about telescope alignment (polar alignment routine in KStars, and then done again after 'going to' target to make sure image is seeing the right thing.
This imaging set is the first time I used plate solving ever - heard good things about it, but was a little nervous about it being an advanced and therefore complicated process... Wow, at least for what I think I've done with it, it is VERY simple and such a good idea! So, the session consisted of: setup scope, camera, etc, balanced everything then did rough polar alignment via polar scope. This was ROUGH - didn't open the app to see where Polaris should have been, just that it was within the clock on the polarscope - the plan was always to use EKOS to plate-solve the alignment and get polar aligned better this way.

So using the polar alignment routine in KStars/EKOS, it reported some 30'. I followed the routine and ended up with both Alt & Az being green (both < 1').

Then 'goto' NGC7000 and plate solved position (synced the mount position into KStars and it was just off slightly, so did another go-to and after the small motion, a final plate solve showed it centred on the nebula.

So how to plate-solve the image? Can you help there please!

1 hour ago, happy-kat said:

Startools there's a preferred settings and output from DSS for optimum processing which uses a FITS file

Just redoing the stack now following the guides (haven't ever touched DSS settings, so hoping that outputting to FITS is the only real difference)
Anyone had a go at the image?!

Tips on imaging, (stars are saturated me thinks!) and processing really appreciated.

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Ummm, so that's come back showing that it is indeed NGC7000

1161033556_ScreenShot2021-09-10at17_20_41.png.72560c6341eea7f4be50ced351d4f469.png

Looks pretty central too, so have to assume the alignment, guiding etc has been pretty decent.

Anyone care to comment on this assumption as it's my first attempt at this?!

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Oh yes, definitely the right place.  You can clearly see the Cygnus Wall at the bottom right.  The image is rotated anti-clockwise 90° to the usual orientation.  
 

From the result of the second processing, and the wide FOV, it rather looks light you should consider calibrating with some flats.

Tony

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Thanks Tony,
Yep, flats were next on job. If I'm right in thinking this, I can do several flat images and they'll then form a master flat for the DSLR and telescope combo, isn't that right? If I wanted to build a library, ISO really doesn't matter (unlike darks) so several images should do the job...

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Good attempt. This is with StarTools 1.8.512

A few ways to make processing easier:

  • lose the dark frames
  • take flat frames
  • dither between frames
  • clean the camera sensor
  • cover the viewfinder
  • use siril to stack
  • stack using a clipping algorithm
  • enter the correct bayer pattern of your camera

Cheers and HTH.

2127592654_DSSStackOutputa_TIFb.jpg.e36a0ac49982cfc7a3eb85db96c8ab3d.jpg

Edited by alacant
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Sorry I had meant only using astrometry like you have, I was struggling to see the target but that's more my familiarity with the image and my surprise with the differences. The two DSS settings to check particularly would be that the cosmetic tab doesn't have remove hot pixels and that is in stacking settings and for DSS the setting for not white balancing is approximately set.

Edited by happy-kat
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56 minutes ago, pete_81 said:

master flat for the DSLR and telescope combo,

Assuming you never change the orientation of the camera with respect to the telescope and no dust settles on the camera. So, in theory, yes. Realistically perhaps best refreshing flat frames regularly.

 

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In addition to the above I would:

  • experiment with stopping the lens down maybe try one stop to start to help minimise the chromatic aberration and also help with corner star shape

I used too small an ROI in autodev and probably over shrunk the stars, could do with a fresh go to re do the CA reduction the mask was not quite big enough on some stars.

1975347563_DSSStackOutput10092011.3.1.thumb.jpg.841a65477c1b93e195e2b0cbe5aecc3e.jpg

startools 1.7.461MR6 | HLVG plugin in paintshopPro | irfanview for tiff to jpg for upload

Edited by happy-kat
added software
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Hi, had another play yesterday had an idea to deal with the CA strong stars and that was create a star only image (this only holds the stars but no CA bloom) using heal heal out the CA stars and then layer in the star image. It's not the usual way I tackle CA but it was an idea I was going you try.

Also the image is pretty big so I was just going too suggest when in DSS to not use drizzle

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On 10/09/2021 at 17:48, alacant said:

Good attempt. This is with StarTools 1.8.512

A few ways to make processing easier:

  • lose the dark frames
  • take flat frames
  • dither between frames
  • clean the camera sensor
  • cover the viewfinder
  • use siril to stack
  • stack using a clipping algorithm
  • enter the correct bayer pattern of your camera

Cheers and HTH.

Thanks again @alacant for the advice you suggest.

So, asking the dumb questions on each...
Why lose the darks?
Flats are obviously sensible to avoid/compensate for vignettes and dust spots
Dithering, check, was using in the guiding. Think I had it set to 3/4 pixels. Would anyone recommend different settings with focal length of guide scope at half that of the imaging (pixel sizes similar)?
Cleaning sensor, on the list to do at some point, but wanting to do more with setup and post than worry about this just atm.
Covering VF, check
I used DSS via OS-X and Parallels to run Windows. Repeated using the clipping "intersection" mode. Just browsing Siril atm as this works natively on OS-X so might be attractive alternative to DSS. Anyone any opinions on either or?
I've assumed DSS had got the bayer mask correct, and reading around, it looks like the regular RGGB is correct - any reason you say this? Just sanity check?

@happy-kat, thanks for your posts on the image processing. Scope is the StarTravel102 (purchased off SGL and this is the first imaging session it's had with me). I honestly was expecting CA as it's very much a starting telescope, but beats the Tamron500 f/8 mirror lens I'd previously been using and lets me get into imaging with a telescope (so it looks better on the AZEQ6 too!).

I'll do more images but good to know there is some data there.
No surprises, I looked in the red channel and much more structure there, so will also have a try with the Ha and see if I can get more detail out of that. Does plate solving still do OK with such a filter in place or am I about to need a filter wheel to eliminate the requirement of camera on and off to add filters?!

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I'll add a link later to an image to show how capable your st102 is.

The dust bunnies I found were effecting the quality of wipe output I could do.

CA there are several ways of tackling it, if you have a 3d printer I would print an aperture mask to stop it down to maybe f7 or so and try that with brighter targets. Startools also has a fringe killer in the filter module which is easy to use.

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Thanks @happy-kat! It's more the 102 isn't going to match to a Zenithstar, but still give some decent images. I've followed horfield-astro and seen his images initially done with the ST102 so know it's not going to give HST competition, but still very nice images :)
Yep, 3D printer just about to go to work on cable holder for the dovetail, doing some measurements for the mask later this evening, as surprise surprise, clouds forecast!

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On 10/09/2021 at 17:48, pete_81 said:

Thanks Tony,
Yep, flats were next on job. If I'm right in thinking this, I can do several flat images and they'll then form a master flat for the DSLR and telescope combo, isn't that right? If I wanted to build a library, ISO really doesn't matter (unlike darks) so several images should do the job...

The issue I would say in trying to create a flat library is that the flat needs to be taken with the same focas and camera orientation as the lights. So getting this exactly the same each session is unlikely. 

So best to take a set of flats each session.

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