Do I have a problem with my 1600mm pro (PROGRESS REPORT 2 )

[simmo39]

Hi, just looking for a second opinion before i go chasing for replacement or repair. I have been getting bad blooming on my subs with what I can only describe as black holes. At first I thought it was my flats but after doing some subs without flats Im getting the same pattern here are some subs what do you think?

Oii sub mild stretch

Ha sub v little stretch but patches still visible

 

This is a small stack from the other night in Ha Ths bright star doent help but you can see the patches of bloom better. This shows up on all filters with or without darks or flats.

A well cropped image that was been stretched and playyed with to an inch of its lifedut still has the problems showing.

Do I have a problem? The camera is only 5 Months old bought from FLO. Not sure as what to try or do next.

 

 

[steppenwolf]

I don't think this is a camera fault - it looks much more like an optical fault to me as it isn't 'blooming' in the normal astrophotography sense. Blooming is normally a description of 'bleed' from one pixel element to another. This looks much more like a reflection to me. It is a strange one though, I don't recall seeing one like this before.

Have you tried imaging with a different telescope (I am assuming that this is with the 130PDS)?

Have you tried imaging with NO filter at all?

[simmo39]

32 minutes ago, steppenwolf said:

I don't think this is a camera fault - it looks much more like an optical fault to me as it isn't 'blooming' in the normal astrophotography sense. Blooming is normally a description of 'bleed' from one pixel element to another. This looks much more like a reflection to me. It is a strange one though, I don't recall seeing one like this before.

Have you tried imaging with a different telescope (I am assuming that this is with the 130PDS)?

Have you tried imaging with NO filter at all?

Hi, yes its the 130 PDS. I havent tried a different scope, but my first images just after I got the camera seem a lot better this has only appeared in the last month or so.

[steppenwolf]

6 minutes ago, simmo39 said:

Hi, yes its the 130 PDS. I havent tried a different scope, but my first images just after I got the camera seem a lot better this has only appeared in the last month or so.

I guess you have already thought long and hard about any subsequent changes that you have made but in the excitement of the new camera, you may have missed this fault earlier.

I would recommend a series of elimination tests before assuming it is the camera just to be sure:-

1. Test image same region of sky no filter

2. Test image same region of sky no filter, no coma corrector (if you have one installed)

3. Test image same region of sky no filter, no corrector, different telescope

If the problem persists, it is the camera!

[billyharris72]

I reckon this isn't a sensor fault as I have a very similar issue (same camera with a SW 72 ED) with Ha images that doesn't affect LRGB images at all. I haven't got to the bottom it yet but suspect it's some kind of reflection artifact.

Pretty sure it's not amp glow, as nothing like this shows up on my darks.

Billy.

[coatesg]

Are the light/dark patches (I'm assuming we're looking at the background variation?) in consistent places? Can you post a stretched flat/stack of flats?

Have you checked down the optical train for haze/condensation?

[simmo39]

48 minutes ago, coatesg said:

Are the light/dark patches (I'm assuming we're looking at the background variation?) in consistent places? Can you post a stretched flat/stack of flats?

Have you checked down the optical train for haze/condensation?

As far as i can see the  Darks and lights look ok. Here is a flat from my last session

Cant see a lot wrong with it but Ill let others judge as Im no expert.

[simmo39]

Also cant see any misting or condensation, I did think at first this was the problem but it seems to be in the same place on different subs taken on different nights with different filters.

[steppenwolf]

Your flat looks OK although it is offset somewhat so checking your collimation would be a good idea. However, the fault that I believe we are seeing in your image would be a focused source whereas the flat will deliberately be unfocused so it is unlikely to manifest itself in a flat image.

[simmo39]

4 minutes ago, steppenwolf said:

Your flat looks OK although it is offset somewhat so checking your collimation would be a good idea. However, the fault that I believe we are seeing in your image would be a focused source whereas the flat will deliberately be unfocused so it is unlikely to manifest itself in a flat image.

Oh. ok would it show in the dark?

[Adam J]

5 hours ago, simmo39 said:

Hi, just looking for a second opinion before i go chasing for replacement or repair. I have been getting bad blooming on my subs with what I can only describe as black holes. At first I thought it was my flats but after doing some subs without flats Im getting the same pattern here are some subs what do you think?

Oii sub mild stretch

Ha sub v little stretch but patches still visible

 

This is a small stack from the other night in Ha Ths bright star doent help but you can see the patches of bloom better. This shows up on all filters with or without darks or flats.

A well cropped image that was been stretched and playyed with to an inch of its lifedut still has the problems showing.

Do I have a problem? The camera is only 5 Months old bought from FLO. Not sure as what to try or do next.

 

 

Cant see your images from work, but ill ask anyhow. Is it just the micro-lens diffraction pattern?

[simmo39]

18 minutes ago, Adam J said:

Cant see your images from work, but ill ask anyhow. Is it just the micro-lens diffraction pattern?

If I knew what that is i might say yes or no lol

[coatesg]

I think your flats are slightly overcorrecting (judging by the light corners on the OIII sub, but I'd agree that the flats look fairly normal. Quite odd - especially if it was working OK before - my thoughts were that it could be some kind of odd issue with the sensor substrate, but then that would have been there from day one...

It's hard to tell in the images, but it looks like the dark area in the first is lower than the dark area in the Gamma Cas image (unless flipped?). I wonder if this is either overcorrection after all, or possibly some kind of reflection in the tube - is it flocked or just bare?

[steppenwolf]

51 minutes ago, simmo39 said:

Oh. ok would it show in the dark?

I assume you mean dark calibration frame? No it wouldn't show.

[Adam J]

5 minutes ago, simmo39 said:

If I knew what that is i might say yes or no lol

I cant open your images but this is a typical example of what the micro lens diffraction pattern looks like on the ASI1600mm pro for bright stars. Gamma Cas is very bright and would cause this issue. 

If yours looks like this then there is nothing you can do about it, its a "feature" of the camera caused by reflections from the glass that is mounted to the sensor itself.

It shows up strongest in HA.

Adam

[simmo39]

8 minutes ago, coatesg said:

I think your flats are slightly overcorrecting (judging by the light corners on the OIII sub, but I'd agree that the flats look fairly normal. Quite odd - especially if it was working OK before - my thoughts were that it could be some kind of odd issue with the sensor substrate, but then that would have been there from day one...

It's hard to tell in the images, but it looks like the dark area in the first is lower than the dark area in the Gamma Cas image (unless flipped?). I wonder if this is either overcorrection after all, or possibly some kind of reflection in the tube - is it flocked or just bare?

Hi the scope is flocked and part of the focus tube is flocked. On the over correction I have gone from 18000adu flats upto 25000, with no obvious change to the subs. 

[coatesg]

2 minutes ago, simmo39 said:

If I knew what that is i might say yes or no lol

There is microlensing diffraction but that's not the issue here - Gamma Cas shows it ?

Any chance of posting the raw files in fits/xsif with appropriate flats - be interesting to see if the brightest areas in the flats correspond to the areas of darkness in the calibrated frames...

[simmo39]

21 minutes ago, coatesg said:

There is microlensing diffraction but that's not the issue here - Gamma Cas shows it ?

Any chance of posting the raw files in fits/xsif with appropriate flats - be interesting to see if the brightest areas in the flats correspond to the areas of darkness in the calibrated frames...

Yep will try to do that, how is the best way to post xsif files? sorry a bit of a luddite with these things.

 

[Laurin Dave]

Hi,

I had a similar problem with my ZWO Ha filter, are you by any chance using unmounted ZWO filters? Are they in the right way round?  It might be light reflecting off the unblackened edges of the filters.  I found it much worse with my ZWO Ha than their RGB.  Do you get the same issue with RGB filters?  What sort of targets/filters have previously given no issues.   To rule out the camera maybe you could try rotating the camera relative to the telescope and filter wheel using a spacer and reshoot the same target to see if the problem moves with the camera.  Also shoot an area devoid of bright stars to see if its caused by reflections from them. Also ZWO now do plastic masks to fit round the filters to combat the problem.. they have also recently redesigned their narrowband filters.

Hope thats of some help

Dave

[simmo39]

44 minutes ago, Laurin Dave said:

Hi,

I had a similar problem with my ZWO Ha filter, are you by any chance using unmounted ZWO filters? Are they in the right way round?  It might be light reflecting off the unblackened edges of the filters.  I found it much worse with my ZWO Ha than their RGB.  Do you get the same issue with RGB filters?  What sort of targets/filters have previously given no issues.   To rule out the camera maybe you could try rotating the camera relative to the telescope and filter wheel using a spacer and reshoot the same target to see if the problem moves with the camera.  Also shoot an area devoid of bright stars to see if its caused by reflections from them. Also ZWO now do plastic masks to fit round the filters to combat the problem.. they have also recently redesigned their narrowband filters.

Hope thats of some help

Dave

Hi Dave. im using baader 1.25 filters. Havent got any RGB filters yet I have had ago at a few targets and as I said earlier its only on the last couple that the problems have started. The Pacman target I did doesnt seem to have any realy bright stars yet im getting the problem.

[simmo39]

3 hours ago, steppenwolf said:

Your flat looks OK although it is offset somewhat so checking your collimation would be a good idea. However, the fault that I believe we are seeing in your image would be a focused source whereas the flat will deliberately be unfocused so it is unlikely to manifest itself in a flat image.

 

Hi, Would the bad collimation be the problem or is it in the focus tube and attachments ( CC and filters)

[steppenwolf]

No, bad collimation is not what is causing the huge halo issue I'm afraid.

[simmo39]

4 minutes ago, steppenwolf said:

No, bad collimation is not what is causing the huge halo issue I'm afraid.

Sorry to be a pain, do you think its more of an internal reflection than a sensor issue?

[steppenwolf]

5 minutes ago, simmo39 said:

Sorry to be a pain, do you think its more of an internal reflection than a sensor issue?

Absolutely, this is what I have been saying all along?

8 hours ago, steppenwolf said:

I don't think this is a camera fault - it looks much more like an optical fault to me as it isn't 'blooming' in the normal astrophotography sense. Blooming is normally a description of 'bleed' from one pixel element to another. This looks much more like a reflection to me. It is a strange one though, I don't recall seeing one like this before. 

Have you tried imaging with a different telescope (I am assuming that this is with the 130PDS)?

Have you tried imaging with NO filter at all?

 

[Laurin Dave]

23 minutes ago, simmo39 said:

Hi Dave. im using baader 1.25 filters. Havent got any RGB filters yet I have had ago at a few targets and as I said earlier its only on the last couple that the problems have started. The Pacman target I did doesnt seem to have any realy bright stars yet im getting the problem.

Not ZWO filter issues then... hmm perplexing..  Hope you get it sorted soon

Dave