Webcam calibration Frames

[kookoo_gr]

the last months i am imaging with a powermate 5x at jupiter with my 8'' f/6 newton and the dust particles that are on my mirrors are starting to give on my nerves. i cleaned the mirrors as best as possible (i used the mirror cleaning process that everybody do) but it is impossible to remove every tiny spec of dust. so i would like to know how can i take the calibration frames for my spc900nc. the most obvious answer is to capture a video of 1200 frames for dark (this the most common duration of my videos) but what about the flat and bias frames? do i need only one video or say 10-15 videos for each calibration frame?

also i would like to know hot to process these videos in order to get the master dark,flat,bias frames

[jgs001]

I've used a dark AVI, and I'm not sure it really helped much in the processing. I've tried a flat avi, but I have to admit the resulting image has always come out rather weird, and with my mono camera (for some reason) turned the resulting stacked image with the flat applied purple... However, in Regi 5.1 load the AVI and in the Flat/Dark/Ref drop down menu, you have the option to create an appropriate frame. let it run, then use the same menu to use that frame during processing.

[Starblazer]

Chances are, the dust you cannot move may be on the chip mate.

Have you had a closer inspection to see if there be any dust bunnies or maybe something on the filter?

Dust on mirrors hardly, if ever effects the images from what i've seen.

[kookoo_gr]

well now that you say at my uv/ir cut filter there are dry humidity smudges but i don't think they are the cause for the dark spots at my images since my camera chip and barlow lenses are clean. i will clean my filter just in case with my baader cleaning fluid and i will report if things get any better

[TopHouse]

I wouldn't mind betting it's not on your filter but on your chip, correct me if i'm wrong here but I bet without the barlows, the spots are either not there or hardly there at all.

Do they look like tiny dark spots with a lighter ring round them?

Here's what to do :-

Unscrew the nosepiece from the webcam, take a couple of good quality cotton buds, ie johnsons, not the superdrug rubbish! Wet one end of one liberally with isopropyl alcohol and gently 'mop' the chip surface with it, be thorough as for some reason, those spots can be hard to remove sometimes, use the dry end then to gently polish the chip as isopropyl left to evaporate will leave a slight residue. If necessary repeat the mopping process.

DISCLAIMER

Do NOT have the webcam powered up when doing this, and I take no responsibility if you mess up your chip, I have performed the above several times on different cameras including SPC900 and if performed properly it works perfectly.