ASI 178MM and ASI 183MM fixed pattern noise?

[Merlin66]

Have any users had issues with FPN with these cameras?

There’s a lengthy thread over on CN. Just google for sample images.

I returned an ASI 183MM and replaced it with an ASI 1600 for my solar imaging.

Looks like the ASI 178MM has the same issues.

Any comment/ feedback??

[vlaiv]

I'm trying to find the thread you are referring to - but failing.

Not sure what issues with FPN are you having?

I experienced both PRNU and Telegraph type noise with my ASI1600.

I also have ASI178mc cooled version. What should I be looking at? Looking at master dark from this camera - there are vertical and horizontal bands - but I did not notice those in final images - I guess those calibrate out?

That is my master dark binned x6 and insanely stretched.

 

[Merlin66]

https://www.cloudynights.com/topic/700403-pattern-noise-with-asi178mm-non-cooled-with-h-alpha-imaging/

I work at 1x1 binning and the background “pseudo Bayer matrix” is an issue when solar imaging.

 

[vlaiv]

Ah yes, I have that on my ASI1600 as well.

I did not notice that on my ASI178 because I did not do narrowband imaging with it and it is color sensor so it will have bayer matrix anyway - but it is there on ASI1600 as well.

For DSO imaging - it can easily be solved with flats. Here is 1600% (nearest neighbor resampling) zoom of my master flat for Ha (DSO kind - not solar):

Can't you fix that with flats?

[Merlin66]

Vlaiv,

Getting good Ha narrowband flats for solar imaging is still a "black art"...............

[vlaiv]

1 minute ago, Merlin66 said:

Vlaiv,

Getting good Ha narrowband flats for solar imaging is still a "black art"...............

Maybe you could just extract PRNU information with DSO Ha filter and flat panel?

[vlaiv]

Just checked - sensitivity difference seems to be 2-3% in regular Ha

[Merlin66]

What bandwidth?

Solar is 0.3A Ha bandwidth.

 

[vlaiv]

7nm - Baader Ha filter for DSO