red blotchy background with asi294mc pro - Forums

Topic starter

Apr 23, 2022

hi everyone! I recently got my first Astro dedicated camera, the asi294mc pro, and I've been having issues with a red blotchy background in all of my pictures, they all have the same pattern and only show in the red channel. I've seen in other forums that this is believed to be an issue with the camera sensor itself, but I just want to know if anyone has found a way to make it less visible or help in any way.
Below I'm going to post some pictures with examples of what's going on. I'm posting my Leo Triplet and California Nebula image split RGB channels which shows the blotchy pattern, also the second picture is one of my flats for the Leo triplet, where you can slightly see the pattern shown there. (I've tried everything with flats, different exposure times, dark flats, shooting with a light source, just pointing to the sky in the daytime, I've tried many things, but nothing helps)

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Jim Matzger

Apr 23, 2022 · Edited: Apr 23, 2022

Yep, I get the same thing. I have had to process it out. Nice camera for the price, but sadly I have had to upgrade to the ASI2600MC.

Greisy Valdes

Topic starter

Apr 23, 2022

Jim Matzger:
Yep, I get the same thing. I have had to process it out. Nice camera for the price, but sadly I have had to upgrade to the ASI2600MC.

***Unfortunately, I cannot afford to get any other camera at the moment, I just got this one so I have no option but to deal with it, just hoping I can find some type of fix that will at least help me processes it out.

Jim Matzger

Apr 23, 2022

Try Gradient Xterminator.

Padraig Farrell

Apr 23, 2022

Hi Greisy

I the same issue and got a lot of it out with…

A:

flats over 4 seconds and set at 50% adu / histogram. At the recommend -10’C.

dark flats set the same. ( use these as bias )

I think I did 100 of each but that’s probably over kill.

50 Darks as per normal.

B:
integrate dark flats. Master Dark Flat

Calibrate darks using master dark flats as bias.

integrate darks …Master Dark

Calibrate Flats with master dark flats

now you have the Masters.

C:
Calibrate Lights using Masters
but …
Master bias use dark flat and tick calibrate

master dark BUT DON’T tick calibrate and
BUT DON’T Optimise.

master flat BUT DON’T tick calibrate.

Now you can go on to Debayer and star align. Etc.

I’m a bit new to this myself , but this gave me the best results so far. There is a slight tinge of green but it even across the image, which can be processed out latter.

just to add…
I use a cheap tracing pad for flats but now I face it towards a white wall to image the flats. Don’t think it make that much of a difference.

hope this helps

padraig

Greisy Valdes

Topic starter

Apr 23, 2022

Padraig Farrell:
Hi Greisy

I the same issue and got a lot of it out with…

A:

flats over 4 seconds and set at 50% adu / histogram. At the recommend -10’C.

dark flats set the same. ( use these as bias )

I think I did 100 of each but that’s probably over kill.

50 Darks as per normal.

B:
integrate dark flats. Master Dark Flat

Calibrate darks using master dark flats as bias.

integrate darks …Master Dark

Calibrate Flats with master dark flats

now you have the Masters.

C:
Calibrate Lights using Masters
but …
Master bias use dark flat and tick calibrate

master dark BUT DON’T tick calibrate and
BUT DON’T Optimise.

master flat BUT DON’T tick calibrate.

Now you can go on to Debayer and star align. Etc.

I’m a bit new to this myself , but this gave me the best results so far. There is a slight tinge of green but it even across the image, which can be processed out latter.

just to add…
I use a cheap tracing pad for flats but now I face it towards a white wall to image the flats. Don’t think it make that much of a difference.

hope this helps

padraig

*** I'll be trying this with my next image, thank you so much for the help!

Well Written Respectful

Andy W

Apr 23, 2022

Greisy Valdes:
Padraig Farrell:
Hi Greisy

I the same issue and got a lot of it out with…

A:

flats over 4 seconds and set at 50% adu / histogram. At the recommend -10’C.

dark flats set the same. ( use these as bias )

I think I did 100 of each but that’s probably over kill.

50 Darks as per normal.

B:
integrate dark flats. Master Dark Flat

Calibrate darks using master dark flats as bias.

integrate darks …Master Dark

Calibrate Flats with master dark flats

now you have the Masters.

C:
Calibrate Lights using Masters
but …
Master bias use dark flat and tick calibrate

master dark BUT DON’T tick calibrate and
BUT DON’T Optimise.

master flat BUT DON’T tick calibrate.

Now you can go on to Debayer and star align. Etc.

I’m a bit new to this myself , but this gave me the best results so far. There is a slight tinge of green but it even across the image, which can be processed out latter.

just to add…
I use a cheap tracing pad for flats but now I face it towards a white wall to image the flats. Don’t think it make that much of a difference.

hope this helps

padraig

*** I'll be trying this with my next image, thank you so much for the help!

I can second the long flat times and matching flat darks. It calibrates out nicely that way.

Well Written

Padraig Farrell

Apr 23, 2022

No problem,

I struggled a lot with this camera. Even check warranty at one stage after reading some nightmare posts on some forums.
But I’m starting to believe it’s like a wild stallion that needs taming 😃
I’ m a lot further on now and just trying to get my head around pixinsight.
I still have to put an image here…
I’ll brave it some day
let us know how you get on …it’ll good to have a before and after for others. I never kept the bad ones.

regards

Padraig Farrell

Apr 23, 2022

Greisy

just to add

I slowed down the cooling time of camera to 10 minutes in Nina.
just in case I might get a frosting halo in the center.
Don’t know if it works, but no harm since I’m waiting for scope to acclimatise 👍

Greisy Valdes

Topic starter

Apr 23, 2022

Padraig Farrell:
Greisy

just to add

I slowed down the cooling time of camera to 10 minutes in Nina.
just in case I might get a frosting halo in the center.
Don’t know if it works, but no harm since I’m waiting for scope to acclimatise 👍

*** I'll try that as well, by the way, when calibrating the flats with the master dark flat do I put the dark flats under darks or bias? darks right?

andrea tasselli

Frequent contributor

Apr 23, 2022

Are you using an UV/IR cut filter by any chance?

Padraig Farrell

Apr 23, 2022

I use the dark flats as bias , tick cal.
add master dark untick cal. And optimise. Since you already calibrated the darks with the dark flats. Optimise is to with exposures of different lengths probably DSLR. So untick.
As for flats have been already calibrated, we untick that.
that’s my understanding so far 🤪

Padraig Farrell

Apr 23, 2022

andrea tasselli:
Are you using an UV/IR cut filter by any chance?

Hi Andrea
I am using a uv/ir cut filter.
I got it when I got the camera, I can’t remember, but I did the research back then and it hasn’t harmed anything I believe.

Greisy Valdes

Topic starter

Apr 23, 2022

andrea tasselli:
Are you using an UV/IR cut filter by any chance?

* I'm using the L-pro for the Leo triplet and l-enhance for the California nebula. I first used the camera without any filter and saw all sorts of blotches but that was due to my bortle 9 skies most likely

Padraig Farrell

Apr 23, 2022

I’m probably a bortle 4…ish
when the neighbours go to bed and their cat stops setting off motion sensor light. 😃

Well Written Engaging

Greisy Valdes

Topic starter

Apr 23, 2022

Padraig Farrell:
I’m probably a bortle 4…ish
when the neighbours go to bed and their cat stops setting off motion sensor light. 😃

where I live I drive down about an hour to bortle 2 almost bortle 1 skies but run the risk of getting eaten by alligators since its in the middle of the florida everglades but 🤷🏻‍♀️

andrea tasselli

Frequent contributor

Apr 23, 2022

Greisy Valdes:
* I'm using the L-pro for the Leo triplet and l-enhance for the California nebula. I first used the camera without any filter and saw all sorts of blotches but that was due to my bortle 9 skies most likely

Then I suspect a sensor tilt or camera filer holder tilt. The way it behaves isn't normal at all if taken with those filters.

Greisy Valdes

Topic starter

Apr 23, 2022

andrea tasselli:
Greisy Valdes:
* I'm using the L-pro for the Leo triplet and l-enhance for the California nebula. I first used the camera without any filter and saw all sorts of blotches but that was due to my bortle 9 skies most likely

Then I suspect a sensor tilt or camera filer holder tilt. The way it behaves isn't normal at all if taken with those filters.

I place the filter directly into the telescope, no filter drawer, but I will read into sensor tilt and see if that could be causing any issues, thank you!

Mike Dobres

Apr 23, 2022 · Edited: Apr 23, 2022

Greisy Valdes:
andrea tasselli:
Greisy Valdes:
* I'm using the L-pro for the Leo triplet and l-enhance for the California nebula. I first used the camera without any filter and saw all sorts of blotches but that was due to my bortle 9 skies most likely

Then I suspect a sensor tilt or camera filer holder tilt. The way it behaves isn't normal at all if taken with those filters.

I place the filter directly into the telescope, no filter drawer, but I will read into sensor tilt and see if that could be causing any issues, thank you!

Hi Greisy, your last comment got me thinking. Is your filter too far from the sensor? This can cause heavy vignetting and star halos due to back reflection from the filter to the sensor. Both get worse the further your filter is from the sensor. I initially had problem with vignetting. So, I now screw the filter directly into the 42F-42F adaptor , that comes with the camera, so its sits a few mm above the glass just above the sensor. of my 294MCpro. In other words as close as is physically possible. I do this with all filters (UV-IR cut, L extreme etc.). I am a relative newby, I've had this camera almost exactly a year, and I find it produce great results with my very basic Dobson set up. Just a thought. Worth experimenting.

Helpful Supportive

Greisy Valdes

Topic starter

Apr 23, 2022

Mike Dobres:
Greisy Valdes:
andrea tasselli:
Greisy Valdes:
* I'm using the L-pro for the Leo triplet and l-enhance for the California nebula. I first used the camera without any filter and saw all sorts of blotches but that was due to my bortle 9 skies most likely

Then I suspect a sensor tilt or camera filer holder tilt. The way it behaves isn't normal at all if taken with those filters.

I place the filter directly into the telescope, no filter drawer, but I will read into sensor tilt and see if that could be causing any issues, thank you!

Hi Greisy, your last comment got me thinking. Is your filter too far from the sensor? This can cause heavy vignetting and star halos due to back reflection from the filter to the sensor. Both get worse the further your filter is from the sensor. I initially had problem with vignetting. So, I now screw the filter directly into the 42F-42F adaptor , that comes with the camera, so its sits a few mm above the glass just above the sensor. of my 294MCpro. In other words as close as is physically possible. I do this with all filters (UV-IR cut, L extreme etc.). I am a relative newby, I've had this camera almost exactly a year, and I find it produce great results with my very basic Dobson set up. Just a thought. Worth experimenting.

I dont have my gear set up right now since the weather here is terrible during spring and summer, but I will see if theres a way I can attach the filter closer to the sensor, if not, Im guessing a filter drawer could be an option. I will first try with what I have, because what you pointed out makes sense, thank you!

andrea tasselli

Frequent contributor

Apr 23, 2022

I had the filter further away, at the end of the focuser adaptor so I guess 70 mm away from the sensor and I had no issue whatsoever, either with vignetting or weird halos. Same camera, same filter (2").

Mike Dobres

Apr 23, 2022

andrea tasselli:
I had the filter further away, at the end of the focuser adaptor so I guess 70 mm away from the sensor and I had no issue whatsoever, either withvignetting or weird halos. Same camera, same filter (2").

Interesting - but by moving the filter closer to the camera, could he also thereby reduce any possible tilt caused by its current placement in the focuser? At least in his set-up. Simple enough to test - to see if filter position affects his images - whatever the cause.

Ryan Abbott

Apr 23, 2022

I know it's mostly already been said but just wanted to chip in and also say I have the same issue only with my L-eXtreme filter using ZWO's filter drawer.

Flats calibrated it out completely for me. They're usually around 4-5s for me to reach 50% ADU but it will depend on your light source of course. I also only take around 30 flats & dark flats and that is good enough to solve it.

I think a lot of people struggle to take flats correctly and I'd probably be one of them but I use N.I.N.A's flat wizard to take them so - if you can - give that a try as it will pretty much take care of everything to ensure you get proper flats.

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Greisy Valdes

Topic starter

Apr 23, 2022

Ryan Abbott:
I know it's mostly already been said but just wanted to chip in and also say I have the same issue only with my L-eXtreme filter using ZWO's filter drawer.

Flats calibrated it out completely for me. They're usually around 4-5s for me to reach 50% ADU but it will depend on your light source of course. I also only take around 30 flats & dark flats and that is good enough to solve it.

I think a lot of people struggle to take flats correctly and I'd probably be one of them but I use N.I.N.A's flat wizard to take them so - if you can - give that a try as it will pretty much take care of everything to ensure you get proper flats.

I've tried the flat wizard in NINA before but have never gotten it to work, I would have to watch some tutorial to see how it actually is, but I've been taking 4-second flats at 30k ADU with the APT CCD flat aid

Ryan Abbott

Apr 24, 2022

Greisy Valdes:
Ryan Abbott:
I know it's mostly already been said but just wanted to chip in and also say I have the same issue only with my L-eXtreme filter using ZWO's filter drawer.

Flats calibrated it out completely for me. They're usually around 4-5s for me to reach 50% ADU but it will depend on your light source of course. I also only take around 30 flats & dark flats and that is good enough to solve it.

I think a lot of people struggle to take flats correctly and I'd probably be one of them but I use N.I.N.A's flat wizard to take them so - if you can - give that a try as it will pretty much take care of everything to ensure you get proper flats.

I've tried the flat wizard in NINA before but have never gotten it to work, I would have to watch some tutorial to see how it actually is, but I've been taking 4-second flats at 30k ADU with the APT CCD flat aid

Yeah I had to change a setting relating to how it handles the raw files for it to work properly, I can't remember it off the top of my head but I'm sure a tutorial would tell you.

That's pretty much identical settings to me, I took all mine using a panel (iPad) and with a white t-shirt, so maybe try that if you're doing it any other way. I doubt it makes much difference either way but you may as well cover all grounds for trial and error. I've heard people say they also couldn't calibrate it out but I don't know what they were doing for flats.

Either way I hope you manage to get a solution, be worth also trying what somebody else mentioned above and putting the filter closer to the sensor.