2600MC Pro - Green tint in raw files - Forums

Topic starter

Dec 20, 2023

I upgraded to the 2600MC Pro a month ago and I've been getting very strange and inconsistent results in individual light files in imaging sessions. In most of the sessions, the image previews were the normal grayscale that Sequence Generator Pro provides. However, a handful of the images had an awful green tint in them but those were easily discarded. The weather finally cleared and I was able to shoot again last night. Every one of my raw files has the heavy green tint. Post processing in PI isn't touching it, even stacked with new flat and bias files. The tint isn't as strong in the flats but I can see echos of it. Looking at the camera settings I see that it's detecting RGGB and that matches the value in the fits header. Looking at the histogram in a fits viewer it's clearly green heavy and overpowering the other channels.

Has anyone seen anything like this in the past? I've changed the USB cable, updated to the latest driver version, and installed the latest firmware on the camera. Nothing helps.

Well Written Engaging

Tom Boyd

Dec 20, 2023

Assuming this has just been screen stretched with colors locked together, kinda looks normal to me. If you unlock the colors before screen stretching it should look more like you would expect. Have you stacked, extract the background, and color calibrate the result? That should take care of the green tint…

Jerry Gerber

Perfect post

Dec 20, 2023 · Edited: Dec 20, 2023

Did you shoot that with a filter? The kind of green cast that OSC images often have is more subtle, nothing like the image you posted. Did you do any processing at all with it?

In PixInsight, there's a process called "SCNR" which removes a particular color cast. Removing a red, green or blue color cast is easy. If you need to remove cyan, magenta or yellow color cast, invert your image and use red (cyan), green (magenta) or blue (yellow) and then re-invert the image.

I downloaded your image and tried to color correct it using SCNR but it's far too green to get an acceptable result with that process. If you haven't done any processing and you did not shoot using a filter, I suspect there *might* be a problem with your camera. I have the ASI2600MC and have never seen that.

Well Written Helpful Insightful Engaging Supportive

Sterling DeRamus

Dec 20, 2023

Got the same camera. Never seen this.

Loran Hughes

Perfect post

Dec 20, 2023

This is completely normal. When you use the Screen Transfer Function to stretch in PI, make sure the RGB channel link icon (top, left side of tool) is de-selected.

Well Written Helpful Concise

Matt Crognale

Topic starter

Dec 20, 2023 · Edited: Dec 20, 2023

That's an unlocked screen stretch of a single frame. Attaching an unlocked and locked screen stretch of the stacked output. I've done the extraction, calibration, etc with no real impact on the amount on the end result. I can get the gradient under control but the colors are still horribly off.

The really crazy thing? If I use SCNR to reduce the green channel the result is almost a grayscale image.

Al Haines

Dec 20, 2023 · Edited: Dec 20, 2023

Did you happen to crop first? or was it at the end of the processing?

Is the previous camera's specs being used?

Best,

Matt Crognale

Topic starter

Dec 20, 2023

Jerry Gerber:
Did you shoot that with a filter? The kind of green cast that OSC images often have is more subtle, nothing like the image you posted. Did you do any processing at all with it?

In PixInsight, there's a process called "SCNR" which removes a particular color cast. Removing a red, green or blue color cast is easy. If you need to remove cyan, magenta or yellow color cast, invert your image and use red (cyan), green (magenta) or blue (yellow) and then re-invert the image.

I downloaded your image and tried to color correct it using SCNR but it's far too green to get an acceptable result with that process. If you haven't done any processing and you did not shoot using a filter, I suspect there *might* be a problem with your camera. I have the ASI2600MC and have never seen that.

It's the same with or without a filter in place. Last night I had the L-Pro installed but when I shot on the new moon I didn't use one and still saw a decent number of images with that tint. I'm leaning towards it being an issue with the camera at this point. Using SCNR on a stacked image, the result is almost grayscale.

l'AstroVan

Dec 20, 2023

Hello Matt
perhaps use the RGGB for Debayer process and, when you get the image of pretreatment (green image I think) you apply the process "automaticbackgroundextractor" or "dynamicbackgroundextractir"
With Pixinsight of course

Brian Puhl

IOTD Staff

Dec 20, 2023

Almost looks like a debayering issue. There's no red in that Histogram at all.

See if you can upload a raw sub for one of us to debayer for you. Disclaimer, make sure you strip the location data from the header if you image from your backyard, for security reasons.

Helpful Concise

Matt Crognale

Topic starter

Dec 20, 2023

Al Haines:
Did you happen to crop first? or was it at the end of the processing?

Is the previous camera's specs being used?

Best,

The crop was done at the end of the WBPP run. I double checked and the equipment profile is using the specs for the new camera. This is so bizarre.

Matt Crognale

Topic starter

Dec 20, 2023

Brian Puhl:
Almost looks like a debayering issue. There's no red in that Histogram at all.

See if you can upload a raw sub for one of us to debayer for you. Disclaimer, make sure you strip the location data from the header if you image from your backyard, for security reasons.

Max file size is 20M so here's a dropbox link:

sample frame with location data removed.

Jason Coon

Dec 20, 2023 · Edited: Dec 20, 2023

~~Can you upload and share one of the files, perhaps to Dropbox or OneDrive, so we can take a look?~~

Nevermind, you just did, looks like we posted about the same time. I'll take a look.

Brian Puhl

IOTD Staff

Dec 20, 2023 · Edited: Dec 20, 2023

I went through every possible debayer pattern in Pix, VNG does not work at all, bilinear with RGGB made the most sense, but the results were just like yours, very green.

Red and blue channels are completely absent of signal, nothing at all.

I'd say something is wrong with your camera. Double check your power source maybe, as a last resort.. but I don't think it's saving things properly.

Dan Kearl

Dec 20, 2023

I downloaded the file, ran through APP, opened in Pix, applied SNR.
Looks normal to me.

Brian Puhl

IOTD Staff

Dec 20, 2023

Here is the sub you sent, seperated by color channels. Whats interesting is I don't see the pixel pattern at all in the green channel, which tells me all the data is getting saved to the green channel, no debayer was involved during the save. Could you have enabled some sort of mono mode, luminance, black and white, or something to this effect on accident? I don't know if that's a thing, but that's what it looks like.

Helpful Insightful Concise

l'AstroVan

Dec 20, 2023

The green color is normal at the and of the pretreatment. You just must apply automaticBackgroundExtractor after crop and the image will be allright.

Brian Puhl

IOTD Staff

Dec 20, 2023

Dan Kearl:
I downloaded the file, ran through APP, opened in Pix, applied SNR.
Looks normal to me.

Normal if it was mono, but it's a OSC camera. There should be color.

Jason Coon

Dec 20, 2023 · Edited: Dec 20, 2023

I see your gain is 100 but your offset is 50. Is that deliberate? I looked at one of my own subs for M31 (120s for mine vs. 60s for yours) and there is far more data in mine. My gain is also 100 but I use an offset of 1, resulting in an eADU value of 1.00 while yours is 0.242. I found this on the ZWO website:

Understanding the unity gain and offset the cameras - ZWO User Forum (astronomy-imaging-camera.com)

--------------
6. What is offset and why/when use it? (seems to lower constrast)offset is just avoid data clip by zero, so you don't need to worry about it because our ASCOM driver already set it well

7. Is there a way to compute or test to determine the ideal offset to use? I read people using histogram median values from bias frames.just make sure all data higher than 0
--------------

This is why I just leave mine at 1. Maybe try recapturing with Offset at 1 instead of 50?

Helpful

l'AstroVan

Dec 20, 2023

The process SNRC IS very destructor and must be use just to kill green very softly

Peter Graf

Dec 20, 2023

Once had something similar, when I used calibration frames for stacking in Pixinsight that have been taken with another software. I do imaging with Nina and Indigo, and both need their own darks, flats, etc.
Think they they have some different implementation of the fits format.

Matt Crognale

Topic starter

Dec 20, 2023

Jason Coon:
I see your gain is 100 but your offset is 50. Is that deliberate? I looked at one of my own subs for M31 (120s for mine vs. 60s for yours) and there is far more data in mine. My gain is also 100 but I use an offset of 1, resulting in an eADU value of 1.00 while yours is 0.242. I found this on the ZWO website:

Understanding the unity gain and offset the cameras - ZWO User Forum (astronomy-imaging-camera.com)

--------------
6. What is offset and why/when use it? (seems to lower constrast)offset is just avoid data clip by zero, so you don't need to worry about it because our ASCOM driver already set it well

7. Is there a way to compute or test to determine the ideal offset to use? I read people using histogram median values from bias frames.just make sure all data higher than 0
--------------

This is why I just leave mine at 1. Maybe try recapturing with Offset at 1 instead of 50?

I set the offset to 50 based on a few threads I read here and on CN. In theory it will be another clear night tonight. I'll adjust the offset to 1 and see what comes from it. The other thing I think I'm going to do is have the sequence take a series of exposures at 60s, 120s, 180s, 240s, and 300s to compare the results. if the change in offset clears helps with the green tint, a longer exposure may provide more valid data to work with.

I'm still not 100% convinced that there isn't a problem with the camera itself but I'd like to try everything I can before starting an RMA / warranty replacement process.

Jason Coon

Dec 20, 2023

Good idea, it would suck to RMA a good camera! I'm guessing that with offset at 50 and only 60s exposures you are likely clipping all the blue and red, given that they each only account for 25% of the data.

Helpful Insightful

SemiPro

IOTD Staff

Perfect post

Dec 20, 2023 · Edited: Dec 20, 2023

Something is very wrong here. The 2600MC follows a RGGB bayer pattern, but the values on your R and B pixels are essentially zero and do not vary. Either Sequence Generator Pro is doing something really funky, or your camera is failing to read the R and B values from the sensor.

This is over a star. It doesn't matter where I check on the image, values for the R and B pixels are always 0.0076.

Try a different acquisition program and if that does not work I think you are going to have to RMA the camera. The fact that it was intermittent before becoming a permanent issue suggests to me its a mechanical fault in the camera.

You don't even have to use the night sky to test. Your problem is that you are getting no values for R and B, so you should just be able to test this by pointing your telescope at literally anything.

You are looking for variations in the R and B pixels. If there are some then you know that the camera is doing something.

Helpful Insightful

Gaillard Jérôme

Dec 21, 2023

I’ve got this camera too. I have never seen such a thing. Probably your camera has got a problem.
If you belong it since just a month, I believe you should use the guarantee.

Related discussions

Review of my QHY600M Camera

I've been getting very good results with the QHY600M and posted a review here for those interested: Link:https://astrogeartod...y600m-reviewed/ Latest image with the camera:https://www.astrobin.com/vxsvh4/ .

Camera comparison relevant; user experienced with QHY600M might offer insights.

Jul 11, 2022

Issue in frames calibration?

Hi everyone, this is a long post, but it’s needed to provide proper context. Thanks in advance to anyone willing to read through it and help me figure things out! I’ve been struggling for days with what seems to be a calibration issue (or possibly a ...

Calibration frames issue may cause color tint artifacts in raw files.

Jul 8, 2025

Do you know what is wrong with my image capture?

I've been troubleshooting my imaging on the Lobster Claw Nebula over a few sessions now. I have an artifact that I'm stumped as the the problem. 1. Collimation has been verified to be good 2. Tilt has been verified to be little or none 3. Foc...

Similar image capture artifact troubleshooting relevant to green tint problem.

Aug 15, 2025

Flat Darks prep and use in PI

Recently, I switched from the ASI 2600MC to the ASI2600 MM Pro with LRGB filter wheel. It's been a complicated journey for sure. Im trying to figure out dust motes, flats etc and was really stumped. I often find numerous dust motes in my my linea...

Flat darks calibration directly relevant to ASI 2600MC color issues.

May 25, 2025