[RCC] IC 1396 -- First light on William Optics Pleiades 111 and first attempt at "real" astrophotography Requests for constructive critique · Gleb Polyakov · ... · 8 · 426 · 1

Zeromantic 0.00
...
· 
·  1 like
·  Share link
After decades of wanting to buy a telescope and get into astrophotography, I finally pulled the trigger on getting the rig of my dreams. This is my first attempt at using the telescope, using a monochrome camera, and at stacking/processing a photo in Pixinsight. I basically just watched a bunch of youtube videos and used a lot of ChatGPT to learn how to do everything.

I'd really love any feedback at all, as I'm literally a rank amateur here and would love to understand how to improve.

For this picture, I specifically am confused as to why I can't get it to be more red after combining the color channels, especially since it's mapped in HSO and my H-alpha channel was far and away the strongest there...



Workflow:

Stacked in Pixinsight using WBPP and 2x drizzle (dithered every sub-frame) -- I took bias frames but don't have any darks or flats. I heard I don't need darks with the ASI2600MM, and I couldn't figure out how to take flats (tho have ordered an EL panel). In this step I also combined different exposure times into a single stack, which idk if that's a good or bad idea. I also have pretty drastically different levels of exposure overall for my H-alpha, O-III, and S-II data. 

Used starXterminator on each HSO raw file to get the stars seperately, then combined them into a seperate layer using Seti Astro's NBtoRGBstars script. Saved that for later.

Then I ran blurXterminator on each layer. Then I combined them all using LRGB combination, and set L to just be the H-alpha layer again. Then I used Seti Astro's Statistical Stretch script to stretch it and ran noiseXterminator. Then I exported the .tiff to DxO photolab to lower the blacks, increase the contrast, and try and get more red and color out of the picture.

Any and all thoughts/criticism welcome!
Edited ...
Like
ScottF 4.52
...
· 
·  1 like
·  Share link
For flats, you can buy a light panel for the scope; the electroluminescent panels are best but get expensive as the size increases. You can use inexpensive tracing tablets with a white cloth over the lens, but be careful with the exposure, as the LED light will produce lines at certain exposure times. Barring those solutions, use an elastic band and a white, unpatterned cloth over the lens, ensuring no wrinkles are present, and point it at the sky opposite the sun(preferably just before sunset or shortly after).
I would use the flats feature in NINA or ASIAIR or whatever program you are using to get the exposure correct. 
I don't know if it's "wrong" to use different exposures on your subject, but it's usually not necessary. So figure out your optimum exposure and stick with that, it's a lot easier that way.
What was your total exposure time for each filter? One thing to keep in mind is that with narrowband, the palette combinations are endless, especially if you start using pixel math.
I'm sure others with way more expertise than me will chime in. Welcome to the crazy and fun world of mono imaging!
Like
Zeromantic 0.00
Topic starter
...
· 
·  Share link
Awesome, thank you!

I ordered this EL panel in the 5" size for $50: https://ellumiglow.com/products/astrophotography-5in-circle-kit

How can I figure out which exposure is optimum for my set-up?

Total exposure for each filter was:
H - 3h 30'
S - 2h 30'
O - 2h 20'
Like
afd33 9.38
...
· 
·  1 like
·  Share link
Gleb Polyakov:
Then I ran blurXterminator on each layer. Then I combined them all using LRGB combination, and set L to just be the H-alpha layer again. Then I used Seti Astro's Statistical Stretch script to stretch it and ran noiseXterminator.

I would say in my opnion the order here is off. LRGB combination is generally for stretched images. Channel combination is for nonstretched (linear) images. I have a feeling that's where you lost your most of your red color, but I'm not sure.

Generally my initial workflow is gradient correction (on individual channels), channel combination, color correction (on LRGB images), deconvolution, noise reduction, star removal. Then since you're using Seti Astro's tools, I would use his star stretch on the stars image, then set that image to the side. Then taking your HSO image, stretch and do all your processing to that before using Pixelmath to add your stars back in.

Alternately, instead of using channel combination, you can stretch each individual channel prior to using LRGB combination and seeing what you get. The more you stretch a channel, the more prominent it will be in the image. With some experimentation you could get more of the colors you like. I personally would just uncheck the L channel and just use the RGB channels.

Another workflow could be something like you can see in this video.

Overall I'd say for a first attempt that is pretty impressive. It's really amazing how "easy" a lot of these tools are making it things. My first image is laughable compared to what you got, but then again I was trying to just use GIMP.  One bit of RCC I would have, and it's kind of unclear, but you'll need to learn when different processes are done, why they are done, and for some processes how things are done manually. All these great scripts and tools we have certainly can help up make nice images, but learning how why and what they're doing is what's really going to help you learn how to make better images.
Edited ...
Like
Zeromantic 0.00
Topic starter
...
· 
·  Share link
Thanks for the feedback! I'll try playing around with the order of operations. Is there any guiding principle in knowing what's best to do on linear vs. non-linear data, or is it a RTFM situation?
Like
akshay87kumar 3.01
...
· 
·  Share link
Gleb Polyakov:
I couldn't figure out how to take flats (tho have ordered an EL panel)

I used to dread about flats, until I realized it was pretty easy to take it at dawn. I tried multiple methods - using white clothes, LED screen (and maybe dreaded the process a lot). Now I just let ASIAIR take over the plan for the night till dawn (using an end-time), and then I take a series of flats using ASIAIR's auto calculated exposure setting when I am about to pack up the rig.
Like
Zeromantic 0.00
Topic starter
...
· 
·  Share link
@akshay87kumar I'll give that a shot! Are you pointing anywhere specific in the sky?
Edited ...
Like
akshay87kumar 3.01
...
· 
·  Share link
Gleb Polyakov:
@akshay87kumar I'll give that a shot! Are you pointing anywhere specific in the sky?

My mount is put on plan to return to home position after completing the plan for the night. That works pretty fine for me. I have been able to get histogram midway using ASIAIR. Somehow for me this is a lot more convenient than messing with cloth, panels and the scope.
Like
Zeromantic 0.00
Topic starter
...
· 
·  Share link
Yeah that sounds way easier, thanks!
Like
 
Register or login to create to post a reply.