RGB combine question

Hello everyone,

should I sum or average the single subexposures of the individual channels in order to obtain the single images to combine in the RGB?

Thanks for any assistance.

Luca

Hi Luca,
I use Sum most of the time. It seems to give me the best results. But you might try both to see what you think.
If you have a little star elongation, then Median seems to help with that, I believe that is the same as average.

hi Luca,

neither sum nor average.
best methode is to sigma clip the single frames, as this will deal with lots of artefacts like hot pixles and noise.
the downside - this methode requires quite a long tota lexposure time.
in case you do not have much exposure time, average would be better.
simple sum augments all kinds of artecats and you run rhe risk of "overexposing" bright parts...
hope this helps...?

Luca,
I would go with average over sum. If you toss a subexposure for tracking errors or jet/satellite, with average, you don't have to worry about radjusting scale on the other channels.

But I agree with Ditmar - I love a sigma clip average. It really eliminates the effects of single frame artifacts. But actually I use a "sigma Combine" average in Astroart (plugin). Is that the same as a Sigma Clip?

Hello again guys!

Unfortunately I don't seem to have much luck with RGB: I've never been able to put together a decent one so far unless I used my OSC camera :C
Now I have 14 10min subs af all 3 channels (the seeing wasn't that good, so I opted for unbinned colors), but my B and G averages are really weak and the final image is truly awful!! I sure need to apply some flats, but I thought that the combined image without flat fields applied would have been full of defects, but not that it would have very weak color. What could I be doing wrong?
What happens is attached here :C :C :C :C

Attached Image: