383L+ Mono and EFW2 issues

[sprinklestudios]

I am getting some really strange dark edges when I mount my EFW2 to my 383L. These do not show up if I shoot without the filter wheel. I have the 7 position wheel with LRGB & Narrowband 36mm unmounted filters from Baader installed. This shows up in each filter. Can anyone explain what is happening? I cannot see anything that would be in the way inside of the filter wheel and again this does not show up when the filter wheel is not attached. I have attached a jpg from one of my stretched flats.

[Chris]

What scope are you shooting through?

Chris

[NickK]

Could be a reflection?

Are the filters square too?

I confess I've always used 2" filters but that looks like some kind of vingetting or optical issue.

[sprinklestudios]

I was shooting through an AT65EDQ for these, but I have also made a make-shift pinhole "camera" out of aluminum foil and got the same dark spots.

Reflections are what I thought it may be too so I read online about the filter direction. I had originally place them with the > on the side of the filter pointing towards the CCD based on what I read, but I found another article that said they should be turned the other direction. I get this both ways.

These are 36mm round filters. ATIK claims you can use the smaller 1.25" filters with no major vignetting but I got the next size larger just to be safe.

[Chris]

It may be worth trying with the filter wheel attached but no filter installed.  If it's some sort of shadowing effect it should be more or less the same.

I use a 383L+ with a Quantum filter wheel and 1.25" filters.  I get a small amount of vignetting in the corners.

Another thing to bear in mind is that image stretching can make tiny differences in level look huge.  What is the actual difference in signal between the brighter and darker parts of the image?

Chris

[sprinklestudios]

I was expecting some vignetting in the corners. I have a pretty good understanding on that. I have just been baffled on the straight edged areas.

I think the reflections may be the only thing it can be. My plan last night was to try the filter wheel without the filters installed, but unfortunately did not get time to do that. Hopefully I will be able to tonight. But if I determine it is the filters, I don't know how to correct this problem. Any suggestions?
I haven't had enough time to shoot with it to determine if flats will take care of this, but I also know that it's better to capture the best image possible without relying on flats.

[sprinklestudios]

Well I was able to test this without a filter installed into the wheel. It is apparently the filters. Here is a flat without a filter installed. Now I am curious to what is causing the diagonal gradients. It could be the quick and dirty stretch I did on it... it shows in this and the autostretch in artemis capture as well.

I know this is ATIK forums and not Baader, but does anyone have any ideas on why the filters would be doing this and how to correct the problem?

Oh and ignore the dusties... didn't blow off the front glass before testing.

[NickK]

Well I was able to test this without a filter installed into the wheel. It is apparently the filters. Here is a flat without a filter installed. Now I am curious to what is causing the diagonal gradients. It could be the quick and dirty stretch I did on it... it shows in this and the autostretch in artemis capture as well.

I know this is ATIK forums and not Baader, but does anyone have any ideas on why the filters would be doing this and how to correct the problem?

Oh and ignore the dusties... didn't blow off the front glass before testing.

Hmm I use the Baader 2" LRGB - I've not noticed an issues with them and seem them as a good mid range filter set.

For the bars - what power supply are you using? Does this happen with the camera just on it's own?

[sprinklestudios]

I am still getting the dark bars on the edges, but good flats do indeed take care of them. I am not going to worry about this too much more as long as my images are looking good as a final output.

I have not gotten the diagonal lines again. I have no idea why they showed up. I image with a couple deep cycle marine batteries and this test was done with the Celeston 7Ah power tank. Maybe that was what caused the diagonal lines?

[MikeM]

I have the same setup as you with the same filters and have never encountered this issue. I do use a 13.8 regulated power supply as opposed to a power tank though.