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[Solved] ASI 294 mc Pro processing
OK...this is probably a really stupid question. I just went back to an OSC (ASI 294) from LRGB. Last night was my first use of my OSC. This morning I gave processing a shot. In the Raw/Fits tab I checked Force debayer and RGGB. Setup is GT-71, .8 reducer, optolong ir cut filter, ASI 294 MC Pro, APT.
I tried to run a quick process with no calibration frames just to see how everything looked and every time the result is a rather yellow greenish color. If I uncheck force debayer, it comes out mono.....
Anyone who might share their settings for their 294?.......or maybe I've got something checked that shouldn't be or the reverse......
By the way....My LRGB mono images were just fine......????
If you capture in RAW, then the colour cast is something that can be removed post processing. All the information is there, just the white balance is off.
However, I don't use APT so the "problem" might be the capture, but I'll share my 294MC Pro settings I use with NINA and APP:
- I capture all my images with my 294MC Pro with a Gain of 121 Offset 0. Depending on target: 3-5 min exposures usually (exceptions are Orion and Andromeda for example which require much shorter for my kit)
- I take Flats ending up with an ADU of around 24k (30 Subs)
- I take DarkFlats (same as Flats but with end of scope covered) (30 Subs)
- I don't use Bias
- Darks obviously at same exposure settings and temp as Lights (I have a prebuilt set of Masters)
- I select Force Bayer because OSC
- I load Lights, Flats, DarkFlats, Darks, Master Bad Pixel Map
- Calibrate: I select Average and Sigma Rejection for all Flats, DarkFlats and Darks (if I'm not using masters/new)
- After Analyze, order by quality. In the list I Deselect (or Remove [from disk]) the bad ones compared to my Reference Frame
- Normalize: Regular and Neutralize Background checked
- Integrate: Weights: Quality, Integrate: Average (if more than 30, else Median). Outlier filter: MAD Sigma Rejection.
If your image is still Green - most OSC end up Green cast because RGGB (G = 2x Green here). I do any colour correction in Photoshop (if you use Photoshop Google the free plugin: HLVG which stands for Hasta La Vista Green) and white balances the image. Under Tools there are various things you can try like calibrating star colour or background - or even light pollution. Might be worth trying them, but I definitely prefer to do any colour correction in a more suited tool.
I get consistent results for my setup from the above. I'm sure everyone will have an opinion on every single setting, but this is a recipe - adjust to suit you and your preferences.
Thank you so much for your reply. I appreciate the work flow, it will help a lot.
I think I figured out my issue. As I said, I didn't use any calibration frames, all I wanted was a quick look at the data. on the load panel, I had the "auto-detect Masters & Integrations" box ticked. I'm not sure what this does but from the name I would think that the program is looking for Masters or Integrations that have been previously made. Anyway, I unticked it and the result was a color image at the end of processing. I shut down APP last night and when I came back this morning, opened the program, it was ticked again; so I suppose "ticked" is the default assuming that calibration frames are going to be used. I have no idea what I am talking about....:-). Anyway, when I unchecked the box all seemed to work correctly.
Thank you for the work flow.....very helpful. Fumbling around with bad results is not any fun.
That "Auto detect Masters & Integrations" box should only affect the files that have been loaded... i.e. you load a Master Bias using the Darks load button, and it works out that it's actually a Master Bias from the filename. So I'm *really* curious why it affected processing. Sounds like a bug! That checkbox should not have any impact with Calibration?!
Hmmmm? I'll try it again with the box ticked and un-ticked and report back....standby...probably be tonight before I can get to it...
You should never use offset 0 for any CMOS camera, not even for Gain 0. That will result in clipping dark pixels due to noise. Setting a reasonable offset is specifically to prevent that. I have the ASI294 also and for Gain 121 I use Offset 8.
Just a friendly tip.
😳 Typo!! Should be Offset = 9
Can't remember why I chose 9 though. The default is 15 I think. I may have read somewhere, liked some images and stuck with it.
@heno thanks for the tip 😉 i too have the 294MC-pro and my default unity gain is 120 and offset it 30. Ive never touched these values, can you or anyone please explain the reason and usage for offset and its value please ?
I'm no camera expert, so I base my knowledge on those that are, like Dr. Robin Glover (founder of SharpCap) and Dr. Craig Stark (founder of PHD and Nebulosity a.o.). They say, using my words, that the offset value is there to prevent camera noise (read noise and ADC noise) clipping low signal pixels to black. The offset value makes base value that is slightly larger than what the noise is able to create and is applied to all pixels, thus preventing clipped pixels due to noise. (This is my understanding.)
If you are using SGP, NINA or any similar, take a dark image, 0,5-1 sec using your preferred gain and temperature. Check the median value. It should be between 500-1000 in 16 bit. Don't sweat it. 😀
My camera gives me 536 at offset 8 and 664 at offset 10. Yours may produce different results. Going above 1000 will waste dynamic range for no benefit.
@heno thanks for the info, i will definately look into these settings. cheers 🤗