Those aren't exactly easy targets. The dimmer the target, the longer the integration time you'll need. And some relatively dark skies to extract them from the background. Fortunately, you have a reasonably fast optic—as I posted before, at f/2.8 you'll just need 2-4 hours in reasonably dark skies. And I assume by Canon Mark IV, you have the 5D—a full-frame sensor with big pixels that gather lots of light.
Questions through the chain:
- How did you achieve focus?
- What lens/camera settings did you use?
- How did you stack?
- How did you calibrate?
- How did you stretch?
While I implement several of Roger's ideas in my workflow, I am a disciple of Charles Bracken when it comes to calibration. RawTherapee only takes in 1 flat, so that's all I use—and it works fine. And bias is already in my (roughly) temperature-matched darks, so it's redundant.
Getting nothing in a stretch is unnatural—even a bias frame will have something in the image. Can you post a single sub and/or your initial stack? I prefer 16-bit TIFF for the stack.
1. I used a Bahtinov Focusing Mask I purchased
2. Canon 5D Mark IV, 300MM F2.8 lens, ISO 1600, F3.2 (I stopped down hoping for additional clarity), 10 sec exposure (If i went higher the light polution seem to get pretty bad and the picture just looked over exposed). I do have a decent amount of light polution facing east but I am in a green zone on the Light pollution Map.
3. Used Deep Sky Stacker (using mostly the defaults). 70 images, + darks + Bias + Flats
4. Not sure what you mean by Calibrate
5. Used PS CS6 following a tutorial I found online. I.E. Adjusting levels (but nothing fancy like individual channels)
When I say "nothing" I simply mean no color. When I stretched the Andromeda Galaxy detail came out of the stretch.
Here is a link to a frame I captured (I posted a 5mp shrinked version and the full 20mp version)
I suspect what it comes down to is: I need to find an easier target, I need to take lots more exposures, and I need to learn how to stack/post process them correctly
I attached screenshots of the histogram of the file I shared as well as the plate solve of the region the image captured
P.S. I bought a Orion Atlas Pro AZ/EQ-G as my mount since I thought it would be sufficient for anything I plan to put on it
Best Regards and thanks for the continued feedback
Edited by russellmm, 13 August 2020 - 07:45 PM.