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What am I doing wrong?

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Spad

Spad

Posted
Posted (edited)

Please see red hightlghted in below picture... I take it, this is an amp glow artifact?

I have used darks, flats, and darkflats. Am I doing something wrong?

NGC6888SL Amp Glow.jpg

Edited by Spad
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smashing

smashing

Posted
Posted (edited)

Nice image!

What camera are you using and how did you process it? Can you see amp glow in any of the sets of frames? How long ago were the darks taken? Same temperature and settings as the lights?

Something odd in the bottom right corner as well I think.

The above will hopefully help others help you out :)

Edited by smashing
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900SL

900SL

Posted
Posted

Your calibration is incorrect.

Darks should remove the amp glow. Clearly there is an issue there

Additionally, your right hand edge has a vertical band of artifacts that should be cropped out before any DBE

 

What camera, settings, exposures etc?

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Spad

Spad

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I have amp glow showing on Lights and Darks. I know about the right hand side. This is an uncroppped image.

Light and Dark frames attached (Used autostretch in Siril)

Here is the info you requested...

Camera: ZWO ASI183MC Pro
Gain: 111
Binning: 1x1
Exposure: 300Secs
Temp: -20 (altho I have a horrible feling that I may have had the camera set to -10 when I shot the images. I have a sneaky feeling this could be my issue!)

Dark frames were shot the day after. I was advised I could shoot a library during the day.

Processed in Siril.

Dark_300.0s_Bin1_183MC_20240812-172603_0010.jpg

Light_NGC 6888_300.0s_Bin1_183MC_20240812-023140_0030.jpg

Edited by Spad
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tomato

tomato

Posted
Posted

Yes, I would suggest a mismatch between temp and/or exposure time between the light and the dark frames. I use ASI 178 cameras which have bad amp glow even on a 2 min exposure but this calibrates out 99.9% if the time and temperatures match. There can sometimes be a very small residual artefact in the background but you have to stretch the image to extremes to see it.

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vlaiv

vlaiv

Posted
Posted
21 minutes ago, Spad said:

Dark frames were shot the day after. I was advised I could shoot a library during the day.

This might be the problem, or rather part of the problem.

Nothing wrong with shooting darks during the day, or re-shooting them at any time after if you set your parameters the same.

deltaT of that camera is 35C. If you shoot it during the day - there is simply no chance that you'll hit -20C temperature with it. For that to happen you need ambient temperature to be 15C or less. That simply does not happen during the day in summer.

- check to see actual temperature in fits header (it might be tall order to hit -20C even at night in summer with 35C deltaT camera - you'd need something like deltaT of 45C).

- try to match actual temperature of lights bearing in mind that you can max go 35C below the ambient temperature.

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Spad

Spad

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Sorry noticed an error in my post.

The lights were shot at -20 at night. The darks during the day at -10...

I'll have a look at the exif info!

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vlaiv

vlaiv

Posted
Posted
Just now, Spad said:

The lights were shot at -20 at night. The darks during the day at -10...

You need to match them in temperature to have proper calibration. That will be the issue.

Wait for the night to reshoot your darks to be able to reach -20C, or do it during the day if you can make ambient temperature below 15C.

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TiffsAndAstro

TiffsAndAstro

Posted
Posted
35 minutes ago, Spad said:

I have amp glow showing on Lights and Darks. I know about the right hand side. This is an uncroppped image.

Light and Dark frames attached (Used autostretch in Siril)

Here is the info you requested...

Camera: ZWO ASI183MC Pro
Gain: 111
Binning: 1x1
Exposure: 300Secs
Temp: -20 (altho I have a horrible feling that I may have had the camera set to -10 when I shot the images. I have a sneaky feeling this could be my issue!)

Dark frames were shot the day after. I was advised I could shoot a library during the day.

Processed in Siril.

Dark_300.0s_Bin1_183MC_20240812-172603_0010.jpg

Light_NGC 6888_300.0s_Bin1_183MC_20240812-023140_0030.jpg

did you stack lights darks biases and flats in siril?

you can make a dark library in day time, but you still need to have them match tempreture. i cool my 533 down to -5c which should be doable for my camera even in the heat of an english summer night ;)

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Spad

Spad

Posted
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6 minutes ago, vlaiv said:

You need to match them in temperature to have proper calibration. That will be the issue.

Wait for the night to reshoot your darks to be able to reach -20C, or do it during the day if you can make ambient temperature below 15C.

I had a feeling this might be the issue.....

Thank you all for the advice!

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tomato

tomato

Posted
Posted

It's just a suggestion, but in my experience you don't need excessively low temperatures when using CMOS cameras, the key is keeping the temperature consistent across all types of capture frames. I run my actively cooled cameras at -10 C all year round. The ASI 178s have retro fitted Peltier coolers and can only run at about +3 deg C but that's OK if I keep the temperature consistent.

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tomato

tomato

Posted
Posted
2 minutes ago, ollypenrice said:

Putting the camera in the fridge is the usual solution...

Olly

I tried putting my Moravian G2-8300 CCD camera in the fridge to take darks, it didn't work, the fridge just warmed up.😄

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ollypenrice

ollypenrice

Posted
Posted
1 minute ago, tomato said:

I tried putting my Moravian G2-8300 CCD camera in the fridge to take darks, it didn't work, the fridge just warmed up.😄

As they say in films about man-eating cameras, You need a bigger fridge! :grin:

The Moravian is a big chunk of camera, especially with the built in F/W if you have that. I think the fridge ought to work fine for a small modern CMOS. This was a very standard method with earlier, smaller, CCDs.

Olly

 

 

 

 

 

 

 

 

 

 

 

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TiffsAndAstro

TiffsAndAstro

Posted
Posted

Was 

6 minutes ago, tomato said:

I tried putting my Moravian G2-8300 CCD camera in the fridge to take darks, it didn't work, the fridge just warmed up.😄

Your freezer was already full of other large cameras, I assume.

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ollypenrice

ollypenrice

Posted
Posted
Just now, TiffsAndAstro said:

Lol 

I have a Ferrari branded fridge for my Ferrari projects.

And I have a Bugatti branded leather wallet but its contents won't buy me a Bugatti...

:grin:lly 

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