2023-03-15: APP 2.0.0-beta14 has been released !
IMPROVED FRAME LIST, sorting on column header click and you can move the columns now which will be preserved between restarts.
We are very close now to releasing APP 2.0.0 stable with a complete printable manual...
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OK, here's the problem: for some reason Stellarmate won't play nice with my mount so I'm confined to 45 second subs. A few nights ago I took about 200 45 sec subs at ISO800 with my full spectrum modded Pentax K-5 DSLR and a 300/4 lens at the half stop between F/4 and f/5.6 in my Bortle 4 backyard. I see some stars and I know that the horsehead and flame should be in the frame (a quick capture at ISO 3200 showed them quite clearly). When I stack the subs (and bias frames, no darks or flats), I get the serious data warning, but go ahead anyway. The final stack at 16.306 seconds exposure, shows nothing. Even when stretched to the max, there's no nebulosity, just some stars.
What could cause this and how would I be able to deal with this (other than trying to get Stellarmate up and running to enable autoguiding)?
Many thanks in advance!
Hans
Dear Hans,
Do I understand correctly that you are only using lights and bias frames? In that case the warning indicates that either
- your bias are not compatible with your lights in terms of sensor gain and or offset
- your lights are simply exposed to shortly
- Or the bias are not in fact bias but something else... how do the bias frames look?
It definitely sounds like the bias subtraction subtracts much more than only the bias signal, so maybe you even have a light leak in your optical train?
Mabula
Dear mabula.
Yes, I have shot only lights and bias and in the meantime I've shot flats as well. The sensor gain for all of them is ISO800 and I can share a bias frame tomorrow when I have access to my data again. I guess this may be down to the lights not being exposed long enough, but that makes me wonder how I can determine whether there's enough signal in them? Is there a metric for this?
I don't think there's a light leak as the lens and camera a covered during the imaging, as is the viewfinder. Is there a way to identify light leakages (perhaps stretching a dark to the extreme?)
I'm about to process a dataset taken with a different DLSR and if that doesn't have the same problem/warning, I'll share that as well.
Many thanks,
hans
It would be the easiest if we can have a look at some of the data indeed. You can upload 10 lights, 10 bias and 10 flats (if you have those) that display the issue to our server.
Hi Vincent,
Apologies for taking so long, but things hot swamped a bit in my inbox. Anyway, I've uploaded the lights and bias frames. No flats for this session, I'm afraid. Many thanks in advance!
All the best,
hans
Thank you Hans! Unfortunately I'll be in London tomorrow morning so I will have to look at the data in a week, apologies for the delay as well.
No worries at all! Enjoy London and I'm busy as it is processing my comet data.
Hope to see your comet on the Pentax forum, Hans!
I'll certainly share it as soon as I have wrestled through Photoshop....
