Please help with processing
Posted 09 March 2013 - 05:43 AM
For M31, the total image time was 51 min (30X60s + 43X30s)
For Horsehead, the total image time was 39 min (39X60s).
Darks were taken and everything was combined using DSS.
The problem now is: why are the images so lousy? First of all, the stars in the corner are not sharp at all. Im using a field flattener for the megrez 88, which apparently is not working well with this equinox. Guess I'll have to try another field flattener for that. Second... 51 minutes for Andromeda... I had higher expectations of what it would look like than the above.
Following all sorts of tutorials on the net, I can't manage to get any good images from my processing.
I've uploaded the original stacks (each and one about 100mb in size) in my skydrive:
Anyone here that can give me any good tips?
About a month earlier I took an image of M31 which was only 12 minute total which is looking way better than the one above (51 minutes)!!! What am I doing wrong?
Maybe someone here might try to process the raw stacks above (from the skydrive folder)?
Posted 09 March 2013 - 08:43 AM
As for image density, I think you just need longer subs to really catch the fainter edges. I did some processing on your image (neutralized background and digital development in ImagesPlus) and got this... You need longer exposures...
Posted 09 March 2013 - 03:11 PM
also try to stack without the dark frames. maybe the darks are failed
Posted 10 March 2013 - 04:14 AM
Posted 10 March 2013 - 12:18 PM
Is there any reason you can't access the TIFF-files from my skydrive? It should be no problems? I dont know any other place that allows uploads of >100mb size images.
Posted 10 March 2013 - 02:44 PM
Try to process it with out darks and see what you get..
what DSS version are you using to process?
Posted 10 March 2013 - 06:09 PM
The vertical streaks are likely due to mismatched darks. Make sure you have at least ten darks, taken at around the same sensor temperature as the lights.
Flats (and flat darks) as part of the calibration process will also let you stretch the resulting data more with less side-effects.
And as John says, above, it looks like the sensor (or some optical component) is tilted with respect to the image plane. Stars near the top left look fine, while those on the bottom right are far from it.
Posted 11 March 2013 - 01:22 PM
What do you mean when you say "historgram up to around 2/3 at least"?
This mismatched darks may be correct, as I took all the darks just before finishing the night (but then I took about 30 minutes worth of darks). Maybe I should take darks more often than that. I didnt note how the temperature varied during the night, but will try to do so next time.
Posted 11 March 2013 - 04:39 PM
Some others create a darks temperature library to use the same darks in the future just matching the temperature.
About the histogram, 2/3 or 25% to the left is like a rule of tomb, I have learn that sometimes this will change for a little bit depending of what is your target , a faint object or a bright galaxy, I'm not an expert but this is what works for me.
Posted 16 March 2013 - 05:04 AM