Photoshop workflow help! Adobe Photoshop · Heather Charron · ... · 32 · 1007 · 0

Hcharron 1.51
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David Foust:
Sure thing. I found this YouTube tutorial very helpful for getting started in Siril: https://youtu.be/9K-V2VIcwfQ?si=bbFYqtki3Nd5JBIY

This is exactly what I needed! Thank you!!
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randcpoll 0.90
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If you are one that can learn from reading, find a used first edition copy of Bracken's "Deep Sky Imaging Primer" and get it. More recent editions focus on PixInsight, but the first edition focused on PhotoShop. The great thing about his primer is that it tells you why things work, not just how. It really gives you insight into any software image processing system.
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Hcharron 1.51
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If you are one that can learn from reading, find a used first edition copy of Bracken's "Deep Sky Imaging Primer" and get it. More recent editions focus on PixInsight, but the first edition focused on PhotoShop. The great thing about his primer is that it tells you why things work, not just how. It really gives you insight into any software image processing system.

I actually purchased as soon as I started! But I was definitely disappointed with it focusing almost entirely on Pixinsight. I need to get that 1st edition and save my current one for when I’m ready to upgrade to PI. Thank you for the info!!
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Mag 1.20
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Heather Charron:
Hello! I’m a newbie, started in Oct 2023, and have been doing my best with Photoshop (it’s free with my work and I can’t afford PI yet). I learned a lot from Nico’s tutorials on his channel, Nebula Photos, but I’m wondering if there are any other resources out there that I could refer to? Most of the popular processing tutorials online use PI and it’s just not in my budget right now. Any YouTube channels, forums, guides, etc would be SO VERY much appreciated!! 

Right now, I’m really struggling with my messy backgrounds and trying to get more detail. Obviously there’s a lot I’m also learning with the actual image acquisition. But I’m finding myself clipping the backgrounds and ending up with fuzzy artificial looks galaxies. I know I’m WAY over processing kinda bad data already and there has to be a better way to handle this!  

You can see how bad it is on my astrobin. 

I’m mostly disappointed and frustrated with my galaxy shots. The 8” SCT should be capable of some really great data, I just can’t figure out how to get it. 

I’m using a Celestron NexStar 8SE + 6.3 reducer and an ha-modified Canon EOS 1100D. The telescope is mounted on the SE alt/az mount without auto-guiding (I JUST set it up and can’t wait for a clear night!). My subs are almost always only 8 seconds (with around 300-500 subs total) and I stack in DSS with darks, flats, and biases. I image from my west-facing apartment balcony in a bortle 4.5, and am usually limited to about 4 hours max because I have a ceiling above me and walls on the other side.

Not the greatest set up, I know. But I want to make sure I’m getting the absolute best I can out of it. 

Thank you!!


Heather Charron:
Gabriel R. Santos (grsotnas):
Just a quick comment with hopefully some ideas for you to try.

I think you diagnosed your primary problem well - you are clipping the background way too much. It is possible to stretch well with PS (although, obviously, more astro-related tools like PI will be more powerful). Here are some recommendations:

1) Verify your flats are working well. To do that, have a look at your integrated result in DSS, with a strong stretch WITHOUT clipping the blacks. You can also check it quickly after opening a 16bit TIFF in PS (linear file) and clicking Adjustments > Equalize. 

1a) If your background is reasonably clean, with only a gentle gradient (or better yet, no gradient at all), good! 
1b) If your background shows dust motes, patterns, uneven gradients. Then you might look into your calibration routine with DSS and solve its issue first (for best results).

2) Stretch your image gently. Multiple iterations of small-moderate stretching is always better than a single strong stretch.

2a) Stretch with Levels adjustment layers. Pull the midpoints slider to the left, and DO NOT TOUCH the black point in the first iterations.
2b) Stretch with curves, doing a "Log" curve. NOT an S-Curve => S curves are to increase contrast AFTER the initial stretching has been done.

3) Your goal is not to have a pretty image, but a reasonably flat image which shows the object, but without excessive contrast and without clipping. After this stretching, you may lower your blacks.

4) Use the eyedropper. Make sure your darkest backgrounds is about 20-40 (in 0-255 range). Never zero!

Hopefully this helps! Keep on going.

Best regards and clear skies,
Gabriel

Thank you so much!! I’ll give this a shot today and will post the results!


Somehow I (R. Mag) unintentionally ended up in the quote section, so I'll end up posting here. Just a couple more comments:

1. SCT'S are among the more difficult scopes to use for imaging due to long focal length and are often not as sharp. This scope uses an f2 or so primary, blows it up to f10 via secondary, where upon you reduce it to about f7.

An f5 8" Newtonian will do wonders. Compared to the SCT, it will require half the imaging time.

2. An EQ mount is required.

3. Keep it simple.

4. Thoughts on monochrome multi-filter imaging: don't.
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ImNewHere 1.20
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Here are a few of my older tutorials on suing Photoshop. I use Photoshop and APP on pretty much everything I do here. https://community.telescope.live/articles/photoshop-tutorials/
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Hcharron 1.51
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Thank you!!
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Mag 1.20
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Heather:

You are doing extremely well as evidenced by your posted photos.

Here's a tip on something easy to do that is very impressive.

When imaging a reasonably bright comet, say magnitude 9 or brighter, guide on a star and set your camera to snap a 30 second exposure every minute or so. There are several programs that will animate this, but the easiest I've found is to step outside the astro box and use dumb old freebie Microsoft Movie Maker (or upgrade). It's a snap to drag the frames in place and use no transition. And that's it! You can add movie stuff to it for finishing touches. 

I'm sure there's a more complicated way.

Also, try GIMP if you do have to eventually anti-up for PS. It's almost a duplicate.

Always remember the best LP filter is a tank of gas and an LP map.
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Hcharron 1.51
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That my first time seeing a comet!! I got my telescope in October 2023 and this was the first comet that a beginner could take a shot at. I was freaking out when I saw the fuzzy green ball show up on my computer screen. What a great night!!
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