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Walking on the Moon

Weirds Darks Effect

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I tried to add darks to my Atik images for once, but I'm bemused. The L, R, G and B images are really black and can't be stretched. Here are screen shots of first, the L with darks and then one without. Weird. What's the problem??



Satcking Issue.jpg

Satcking Issue - darks.jpg

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So, I tried StarTools, following this tutorial, but got this hideous image only a third into the tutorial - see screenshot at bottom of this post. I've had nothing but trouble with my Atik the last two times I've used it. Is it me or the camera? I'm about to give up. Fed up, ill, tired and feeling totally useless. Sorry for the rant. Needed to get that off my chest. :crybaby2:

By all means have a go (MediaFire links):














ST Issue.jpg

Edited by Astrosurf
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What's happened is that, presumably, the darks have black clipped the image. This would happen if 1) the darks had a very high signal. Did you make them with the black metal cap screwed on over the chip window? That is the way to do them. If you did them on the scope, and espeically on the Newt, light would get in from various leaks and build up on the darks. This high value would then be subtracted leaving only the brightest signal still in place. 2) The bias signal is in the dark frame. If you subtract both a bias and a dark you will double subtract the bias and black clip the image.

It could also be a glitch in the calibration software.


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Thanks Olly. To the rescue as usual! I got my Atik second hand and don't have a cap for it. Yes, I took darks on the frac with it's dust cap on. Won't do that again!

Any idea why all my RGB subs are soooo noisy? I tried your advice you gave me some while ago, which I used successfully on my M51, but I couldn't get it to work on this one: when you process the L and RGB separately, then add the L as a layer with Luminosity Blending Mode several times, increasing the opacity each time.

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