LRGB Complete Workflow: Part 1 -- Culling Subs & Stacking Data From One Or More Nights

Рет қаралды 1,060

21 күн бұрын

After imaging for one or more nights, there are a pile of subs to organize, cull and stack. Time to open PixInsight and get cracking! We'll review four criteria to effectively cull subs in the SubFrameSelector and how to stack and drizzle data from one or more nights in the Weighted Batch Preprocessor, and go into the reasons behind each processing choice.
This is the first in a four part series covering the technique and theory for LRGB processing. While this information is on LRGB processing, much of it also applies to OSC and narrow band subs, too.
You can view the final image created in the four part process at the Sky Story Astrobin: www.astrobin.com/4jdauk/J/
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Пікірлер: 12

@ShibajiSinharay 20 күн бұрын

Hi, I am using the sigma calculation directly with: StarsSigma > -2 && FWHMSigma < 2 && EccentricitySigma < 2 I think, this saves some of the manual lookup of values and is quite reliable. Please see if this makes sense.

@SKYST0RY 19 күн бұрын

I'll have to take a look at that some time. Anything that saves a step is worth looking into.

@KJRitch 13 күн бұрын

Since I don't use Pixinsight but Siril I guess the equivalent is when you process the stacking outside the process script, in my case OSC_Preprossing, and after registration there is a plot to decide which frames to remove prior to stacking. Other than that I use ASIFitsView to look at each FIT frame to eyeball each frame. Satellite tracks seem to be my most common problem.What calibration type is supposed to remove satellite or aircraft tracks?

@jakomiske217 8 күн бұрын

I use the Sigma Clipping stacking method when stacking my light frames, and I've never had a problem with satellite trails in the final image when stacking with Deep Sky Stacker, Siril, or Sirilic (a stacking extension for Siril). I also have a major airport by me and get a couple of plane trails throughout each night, and it takes all of those out. I've heard that you need to have a lot of light frames (I think at least 50 is recommended) for Sigma Clipping to work well, but if you're taking short sub exposures, like 90s or less, then you probably won't have to worry about that

@jakomiske217 8 күн бұрын

Also, I have PixInsight, but I still prefer to use ASIFitsView whenever I'm able to manually look through my light frames. It's really easy to go through all of them with one hand on an arrow key and the other on the delete key. I also love how many controls you have for auto stretching the image, allowing you to easily see any clouds or haze come through just by auto stretching on a good frame, toggling the autostretch off, and then switching between through your frames

@IronMan-2024 20 күн бұрын

I see you found something more suitable than Blink 😂

@SKYST0RY 19 күн бұрын

Blink is painful to even think about lol

@gingermetallurgist 19 күн бұрын

Hi. What is your procedure/methodology for taking calibration frames? It looks like you don't use standard dark frames? Thanks.

@SKYST0RY 19 күн бұрын

I haven't bothered with dark frames for years. A statistical assessment of the benefit of darks on modern camera sensors shows they barely make a difference. I don't find them worth the effort on any sensors I've used of the Sony 5xx generation. Cuiv, the Lazy Geek did a thorough assessment of this about a year ago. All I use these days are flats and biases. I do have a couple videos out on shooting flats and yet another coming up soon applying another technique.

@davidandersen208 20 күн бұрын

Have you tried NSG? If not I'll pay it fore you so you can use full function of it.

@SKYST0RY 19 күн бұрын

Thank you for the offer. I tried the free version awhile back but it wasn't compatible with drizzling, and I wasn't willing to give up drizzling. The paid version does allow for drizzled outcomes but VisibleDark did an excellent comparison of NSG vs Local Normalization 2 years ago and found that PI's Local Normalization had improved so much that NSG didn't make much difference anymore. Given I am under dark skies and don't ever have to deal with light pollution or any other gradient than what is created by moonlight, I didn't think it was worth it in my circumstances. Neither gradient nor shot (poisson) noise are meaningful issues at my location.