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Video Imaging 101 Questions! (Long)


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Spent up to the hilt on a Watec plus HEQ5 (And general commissioning of a RoRo observatory!), I have been trying a little BASIC [Watec] video imaging. Documentation notwithstanding, I just wonder if I can beg a little clarification on BASIC techniques re. an actual example? :)

Although I've just purchased a Telescope Service 8" F4 imaging Newt(!), I decided, for simplicity (smaller turning circle!), to use my MAK150. With ATIK field reducer, I'm getting about F6...

After a rough polar alignment of the HEQ5, I chose M57 (Hey it's easily found?) as a target! With Watec integration set to "8" (128 frames@ 1/50 sec) and gain to ~75% (Gamma set to "HI") I'm getting actual frames every Five seconds (Gstar software set accordingly) or so, looking like this:

RingNeb01.jpg

FIRST QUESTION: Is the setting "about right"? There is both camera GAIN and CONTRAST in reserve, but I thought that the nebula should appear a tad.... "gauzy" at this stage. Maybe I should INCREASE the gain / contrast? :)

Comment: Woohoo, you can (believe me!) just about see the 15th mag central star. :)

Anyway, I go on to records a video of 200 frames of this ilk. For good measure, I then cover the objective (corrector) and dutifully record 200 dark frames, that look like this:

RingDark.jpeg

Clearly there are some hot pixels (at least!) at these settings. Notwithstanding this, I simply process the IMAGE (only!) video through Registax, with default settings. I "lock on" to M57's adjacent star and stacking (200 frames) produces [with minor twiddling]:

RingNeb.jpg

Believe me, I am well enough (easily?) pleased! :eek:

BUT CLEARLY e.g. the "Hot Pixels" (despite attempts to conceal them!) are now streaked across the frame.

SO MANY QUESTIONS:

1. Could I remove the hot pixels, by using my dark (master dark) frames? Maybe even consider flat frames too? Are such things subtracted piecewise (framewise?) from the TRUE image?

2. Is the drift of M57 (Arc minute over 1000 sec!), typical of (normal!) limitations of the HEQ5 Syntrek's tracking - OR indicative of pathological (quick & dirty) polar alignment? :eek:

3. Where to next? I'd like a (Video) "diary" of my observations. I don't feel capable of (funding!) "proper imaging"... auto-guiding(?) whatever. I sense I can still do something to improve (what for me is!) really exciting stuff!

P.S. Yeah, I'm being a LAZY here. But I feel overloaded at the moment. All this Polar Aligning, EQMod-ing, Collimating - Not to mention carpentry! LOL. How hardcore imagers manage without "observatory staff"... :o

Edited by Macavity
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