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Advice on first video image

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#1 gmussman

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Posted 03 July 2013 - 09:00 AM

Hi everyone,
Appreciate a bit of constructive critism to help me as I learn astrovideo. This is the first thing I've ever managed to get on the screen.
I'm using an 8 inch f4.9 newt on an orion atlas. The collimation is a bit off but I was pressed for time so I left it. The camera is an lntech 300 camera with no mods and a f0.5 focal reducer. The camera was set for electronic iris at x128, and I cranked down the red on the manual white balance.
The picture is an iphone shot of the image on a sony portable DVD player.

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#2 mattflastro

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Posted 03 July 2013 - 07:51 PM

The little donuts you have in the image show it's not in focus .
Buy or make some type of focus assist device.
Hartmann mask, Bahtinov mask, 2 sticks crossed in front of the scope, a piece of cardboard with some holes in it, digital zoom on the camera, something is needed to help focus .
For white balance I use a color bars and gradients target I printed on a sheet of white photoprinter paper. Aim the scope at it at the beginning of your observing session (the target can be close to the scope, it doesn't need to be in focus) , have it exposed correctly (no blown highlights )and adjust manual white balance until the screen image matches the printed target.

#3 GlennLeDrew

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Posted 03 July 2013 - 07:52 PM

M57 has fairly high surface brightness and hence contrast, and so should be visible with less sky glow (unless light pollution/moonlight is strong.) the mottled blue glow of the sky is significantly detracting from the image. Yet the nebula is clearly not over-exposed. I take it your sky was very bright? If so, a nebula filter is warranted.

#4 gmussman

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Posted 04 July 2013 - 07:18 AM

Matt and Glenn,

Thanks as usual for the great advice. That's exactly what I need. I'm making a Bahtinov mask for focusing -- I'll look around for a white balance pattern (and a color printer) to print out.

Glenn, you hit the nail on the head with the light pollution -- I'm in white-zone skies in residential Cincinnati. I was thinking I might have some setting wrong to cause the glow, but you're right, the nebula isn't over exposed. I'll be ordering a UHC filter today, I think.

Thanks again,
Grant






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