swag72 Posted October 11, 2011 Share Posted October 11, 2011 I am sure that I must sound like THE most boring person on here waffling on all the time about my images not being nice an focused across the field. I have posted numerous images in the past to demonstrate this, so won't bore you again at this moment, but just for the sake of clarity want to say the following.1) Focuser and flange as square in the OTA as I think I can ever hope to get - Also no moment, nice and solid.2) Guiding looking good - Cables routed through the mount, nothinh pulling. Again, nice and tight.3) Camera nice and square in the focuser and nice and tight.Using a 0.85x reducer.So, I have a bad bottom left corner, very elongated stars and looking a little out of focus - Focus is spot on with a bahtinov mask - When I move the camera around by 180 degrees the bad corner moves in the same direction as the camera. Nothing else has moved at all. Does that suggest a camera issue or OTA / imaging train issue? I just can not see the wood for the trees. Link to comment Share on other sites More sharing options...
Psychobilly Posted October 11, 2011 Share Posted October 11, 2011 Which camera is this with Sara? Link to comment Share on other sites More sharing options...
Glider Posted October 11, 2011 Share Posted October 11, 2011 :confused:Camera Link to comment Share on other sites More sharing options...
Glider Posted October 11, 2011 Share Posted October 11, 2011 I was going to say something like the chip not being down flat on the camera circuit board but then the distortion would be over the whole FOV.Almost sounds like window is not same thickness in one corner, or part of a protective film has been left on????? Link to comment Share on other sites More sharing options...
swag72 Posted October 11, 2011 Author Share Posted October 11, 2011 1000D Peter - Just trying to get my head clear - If image issue moves with the camera - That's where the problem is right? - Look like you agree Glider? I thought thought that the issue being with the camera would be nigh on impossible. Clip in filter used - All snug and square, clipped in properly. Link to comment Share on other sites More sharing options...
Psychobilly Posted October 11, 2011 Share Posted October 11, 2011 The modified one? Link to comment Share on other sites More sharing options...
Glider Posted October 11, 2011 Share Posted October 11, 2011 Finger print? Link to comment Share on other sites More sharing options...
swag72 Posted October 11, 2011 Author Share Posted October 11, 2011 The modified one?Yes.Finger print?On the sensor? Link to comment Share on other sites More sharing options...
Psychobilly Posted October 11, 2011 Share Posted October 11, 2011 Has anyone ever run one of your full frame images through ccd inspector... Ideally you want a rich star field across the whole of the frame... Link to comment Share on other sites More sharing options...
Glider Posted October 11, 2011 Share Posted October 11, 2011 Yep, a splodge in one corner perhaps. Link to comment Share on other sites More sharing options...
swag72 Posted October 11, 2011 Author Share Posted October 11, 2011 Best way to determine whether this is the case? I don't have the stuff for a wet sensor clean. Will I see it just by looking? Link to comment Share on other sites More sharing options...
Glider Posted October 11, 2011 Share Posted October 11, 2011 Just trying to imagine what could affect one corner:icon_scratch:, if in fact it is just one corner. Link to comment Share on other sites More sharing options...
swag72 Posted October 11, 2011 Author Share Posted October 11, 2011 Yep it is just one corner, with elongated stars and a slight oof compared to the rest of the frame. Fingerprint wouldn't lead to elongated stars though would it? Link to comment Share on other sites More sharing options...
Psychobilly Posted October 11, 2011 Share Posted October 11, 2011 I would ask if anyone could help out and analyse a couple of starfield frames with the camera rotated 90 degrees between each frame... take short(ish) exposure high ISO images... your not after low noise or any great depth... and shorter exposures will help reduce any tracking/alignment related distortionPeter... Link to comment Share on other sites More sharing options...
swag72 Posted October 11, 2011 Author Share Posted October 11, 2011 Will do Peter cheers - I have to say that I am glad it's the camera over the OTA / Imaging train. I was starting to worry it would sffect the new camera. Link to comment Share on other sites More sharing options...
Psychobilly Posted October 11, 2011 Share Posted October 11, 2011 I'm not saying anything till we see some results ... Link to comment Share on other sites More sharing options...
swag72 Posted October 11, 2011 Author Share Posted October 11, 2011 Images will have to wait until tomorrow now as all is packed away - I've only got 2 rotated about 180 degrees at the moment. Link to comment Share on other sites More sharing options...
Glider Posted October 11, 2011 Share Posted October 11, 2011 Yep, analyse some star fields. Link to comment Share on other sites More sharing options...
steppenwolf Posted October 11, 2011 Share Posted October 11, 2011 I can produce the analysis of the frames for you using CCDInspector - in fact I seem to recall that I have already done some for you in the past? What I acn't promise is that I can determine the problem of course, but I have to say that it sound like a camera issue BUT it could be the camera mounting rather than the sensor itself. So much depends on the part of the sensor that you focussed on as well, for example, if you focussed on a star that was off centre to the top right hand corner, the centre and top RH corner could look more in focus than the bottom LH corner?Either way, I'd be happy to run your test images through CCDI. Link to comment Share on other sites More sharing options...
swag72 Posted October 11, 2011 Author Share Posted October 11, 2011 Steve, you are such a darling!! I knew you'd come to my rescue!! Link to comment Share on other sites More sharing options...
Photosbykev Posted October 11, 2011 Share Posted October 11, 2011 do you have access to another camera body that you could use to check if the problem is sensor related? Link to comment Share on other sites More sharing options...
ollypenrice Posted October 12, 2011 Share Posted October 12, 2011 ^^^ is a good idea. Lots of people have a DSLR they could lend you for half an hour. My hunch would be that it won't be Cannon because their tolerances are so tight. OK it might be but I'd be more inclined to suspect the filter or something that happened in the mod. If the problem rotates with the camera then surely it will be the camera? I don't know the filters at all but can they sit out of kilter? Or it could be a bad one with irregular glass.Best of luck.Olly Link to comment Share on other sites More sharing options...
Merlin66 Posted October 12, 2011 Share Posted October 12, 2011 Sara,Olly may have something there....Have you tried the exact same set up but WITHOUT the clip in filter???If you get the same results then it defininately infers an issue with the camera body (somewhere...) if not, then you've identified the clip in filter element is the problem! Link to comment Share on other sites More sharing options...
Psychobilly Posted October 12, 2011 Share Posted October 12, 2011 Put your unmodded body on there without the filter and see how that performs on a starfield?Although if your unmodded camera is a 5D MkII don't do it as the full frame semnsor is likely to throw up all sorts of other questions... and the focuser will have a lot more weight to handle... Link to comment Share on other sites More sharing options...
swag72 Posted October 12, 2011 Author Share Posted October 12, 2011 Cheers for the ideas folks. I'll do a couple of things tonight if it's clear.1) Image with the 1000D without the clip in filter2) Image with the 7D (unmodded) - Has the same APS sensor as the 1000D, won't leave it on long as it's damn heavy!!! Link to comment Share on other sites More sharing options...
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