Anthony1979 Posted April 25, 2020 Share Posted April 25, 2020 ive been trying for days to sort this image out but still not getting any where.. i just dont no where the problem is.. ive tried different settings in dss.. it only seems to be when i add my flats but was told my flats were fine.... this is lights,flats,darks and bias Any ideas please Link to comment Share on other sites More sharing options...
alacant Posted April 25, 2020 Share Posted April 25, 2020 (edited) Hi Tell us what you did to get to this stage. Go through all the light frames and reject any with cloud, haze and any other imperfections. Link us to an example of each type of frame you used. Restack and post a link. Cheers Edited April 25, 2020 by alacant Link to comment Share on other sites More sharing options...
Ant Posted April 25, 2020 Share Posted April 25, 2020 I used to get exactly the same issue, but only occasionally. I never really got to the bottom of it. In the end I used to take three sets of flats. One at my normal ADU count (which from memory was around 20K (1/3rd full saturation)). But because of this issue, I used to take another set at 15k, and another set at 25k. Then if the usual set went a bit Pete Tong, I'd use one of the others, which usually worked OK. Also how many Flats are you using in your stack? If its an even number, remove one... I was always told that it needed to be an odd number for flats, darks and bias frames (never understood why). Ant Link to comment Share on other sites More sharing options...
Freddie Posted April 25, 2020 Share Posted April 25, 2020 If it only happens when you use your flats, obviously the problem must be with the flats. What does your master flat look like? 1 Link to comment Share on other sites More sharing options...
Anthony1979 Posted April 25, 2020 Author Share Posted April 25, 2020 I will put the tiff files on tomorrow... Ive shutter laptop down starting stressed me out I used level and curves in gimp then got frustrated and messed about with everything... Im near enough given up on it all.. Its driving me nuts Link to comment Share on other sites More sharing options...
FaDG Posted April 25, 2020 Share Posted April 25, 2020 (edited) I've had a lot of grief with my flats too! I tried different exposures, different methods to acquire them. Then, recently, I found the solution. How did you shoot those flats? If not already done this way (in which case I don't know how to help), try taking then again tomorrow, in full daylight with a white T-shirt on your lens and pointing opposite side of the sky wrt. the sun. Head for 1/4 ADUs of your full well. It was really the one and only way I solved my flat problem. Edited April 25, 2020 by FaDG Link to comment Share on other sites More sharing options...
Anthony1979 Posted April 25, 2020 Author Share Posted April 25, 2020 I cant take the flats now because ive took the camera off the scope Link to comment Share on other sites More sharing options...
Anthony1979 Posted April 26, 2020 Author Share Posted April 26, 2020 (edited) single flat frame _DSC0001.NEF Edited April 26, 2020 by Anthony1979 Link to comment Share on other sites More sharing options...
Anthony1979 Posted April 26, 2020 Author Share Posted April 26, 2020 single light frame _DSC0007.NEF Link to comment Share on other sites More sharing options...
Anthony1979 Posted April 26, 2020 Author Share Posted April 26, 2020 master flat MasterFlat_ISO400.tif Link to comment Share on other sites More sharing options...
Anthony1979 Posted April 26, 2020 Author Share Posted April 26, 2020 (edited) stacked lights Edited April 26, 2020 by Anthony1979 Link to comment Share on other sites More sharing options...
Anthony1979 Posted April 26, 2020 Author Share Posted April 26, 2020 28 minutes ago, Anthony1979 said: stacked lights M101 TEST 4.TIF 276.49 MB · 2 downloads Sorry this is a full stack of lights,flats,darks and bias... The pic above Link to comment Share on other sites More sharing options...
MarkAR Posted April 26, 2020 Share Posted April 26, 2020 Just done an extreme stretch of the stacked lights and it looks like it might be light pollution. Link to comment Share on other sites More sharing options...
Anthony1979 Posted April 26, 2020 Author Share Posted April 26, 2020 23 minutes ago, MarkAR said: Just done an extreme stretch of the stacked lights and it looks like it might be light pollution. Ive never had this problem from my back yard... Ive done all my imaging from my back yard and this is the first problem ive had... Link to comment Share on other sites More sharing options...
Anthony1979 Posted April 26, 2020 Author Share Posted April 26, 2020 2 minutes ago, Anthony1979 said: Ive never had this problem from my back yard... Ive done all my imaging from my back yard and this is the first problem ive had... The one i put on saying stacked lights was with flats darks and bias. Its not just lights sorry 1 Link to comment Share on other sites More sharing options...
Anthony1979 Posted April 26, 2020 Author Share Posted April 26, 2020 I will do a stack of just lights Link to comment Share on other sites More sharing options...
alacant Posted April 26, 2020 Share Posted April 26, 2020 Hi The single flat frame shows off centre optics. The master-flat less so. the dust has been removed so in that respect, the flat frames are working. The stack shows intense gradient which is not present on the -quite nice- single frame. It looks like there was a change in orientation and /or light leak into camera or telescope when you took the flat frames. It's rescuable, but it needed a big hammer to remove the irregularities. I fixed the stars whilst I was at it; there seems to be coma toward the edges. Anyway, HTH and stay safe. Link to comment Share on other sites More sharing options...
Anthony1979 Posted April 26, 2020 Author Share Posted April 26, 2020 So it is down to my flats being bad Link to comment Share on other sites More sharing options...
david_taurus83 Posted April 26, 2020 Share Posted April 26, 2020 The flats dont match the lights if this is the set that I had a play with. So they can cause all sorts of issues, gradients etc Link to comment Share on other sites More sharing options...
Anthony1979 Posted April 26, 2020 Author Share Posted April 26, 2020 29 minutes ago, alacant said: Hi The single flat frame shows off centre optics. The master-flat less so. the dust has been removed so in that respect, the flat frames are working. The stack shows intense gradient which is not present on the -quite nice- single frame. It looks like there was a change in orientation and /or light leak into camera or telescope when you took the flat frames. It's rescuable, but it needed a big hammer to remove the irregularities. I fixed the stars whilst I was at it; there seems to be coma toward the edges. Anyway, HTH and stay safe. I did accidently remove camera when i was packing everything up forgetting i had to take flats then put it back on.... So is this where i went wrong ( bad mistake) Link to comment Share on other sites More sharing options...
david_taurus83 Posted April 26, 2020 Share Posted April 26, 2020 What software are you using to process after it's been stacked in DSS? Link to comment Share on other sites More sharing options...
alacant Posted April 26, 2020 Share Posted April 26, 2020 4 minutes ago, Anthony1979 said: is this where i went wrong We can confirm or otherwise with a stack of just the light frames. Cheers Link to comment Share on other sites More sharing options...
Anthony1979 Posted April 26, 2020 Author Share Posted April 26, 2020 8 minutes ago, david_taurus83 said: What software are you using to process after it's been stacked in DSS? I use GIMP 2.10 Link to comment Share on other sites More sharing options...
david_taurus83 Posted April 26, 2020 Share Posted April 26, 2020 1 minute ago, Anthony1979 said: I use GIMP 2.10 Does it have a method to deal with gradients? Unless you are imaging from a pristine dark sky location and your optics are spotless then you will nearly always have some sort of gradient to sort out. Have you had a look at any of the dedicated astro softwares? Link to comment Share on other sites More sharing options...
alacant Posted April 26, 2020 Share Posted April 26, 2020 3 minutes ago, david_taurus83 said: nearly always have some sort of gradient Hi The single frame looks pretty good to me. Link to comment Share on other sites More sharing options...
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