Galaxy NGC 4725, one-armed spiral

Astrophotography: share your photos & discuss techniques
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AstroGeek
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Re: Galaxy NGC 4725, one-armed spiral

Unread post by AstroGeek »

Cool stuff, Andy.

Did I mention that your background sky is like black glass??

Steve
Steve L
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menardre
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Re: Galaxy NGC 4725, one-armed spiral

Unread post by menardre »

Andy

Great shot, Looks like your remote observatory is working out well. After searching internet, I would say that your shot is at least as good as any others.

As a novice I have one question... this is an accumulation of several nights shots. What do you do to make sure that all of the pictures (from night to night) are aligned properly?

Currently I use color DSLR, and I try to do all of my astrophotography in one night. Someday I may move up to CCD, but I am not sure how difficult it is to align pictures taken from different nights. I know that SGP has a plate solve function, but I have never tried it.

What do you do??

Roger
Roger M.
Celestron CPC1100 EDGE, Stellarvue 130T refractor dual mounted on iOptron CEM120 on permanent pier mounted in Observatory. Imaging camera ZWO ASI2600 OSC, guide camera Lodestar or ZWO ASI290MM.
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AndyG
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Re: Galaxy NGC 4725, one-armed spiral

Unread post by AndyG »

menardre wrote:I am not sure how difficult it is to align pictures taken from different nights. I know that SGP has a plate solve function, but I have never tried it.
If you already have SGP, you can use it to center your targets. It's quite easy once you have it setup. You specify your target coordinates from a reference image, or get the coordinates from a planetarium program, or (best of all) use SGP's Framing and Mosaic Wizard. SGP points the scope precisely at the target location when you start imaging the target.

SGP relies on third party plate solving software for the centering. You should use PlateSolve2 (free, bundled with SGP) as the primary solver, and local astrometry.net as the fall-back ("blind" solver as SGP calls it, also free). There is plenty of information in the SGP help file on how to set things up, and you can always ask questions in the SGP support forum.

If you do not have SGP, then for target centering you can use AstroTortilla which is a Windows user interface for the astrometry.net plate solver.
menardre wrote:What do you do to make sure that all of the pictures (from night to night) are aligned properly?
My centering routine is similar to how SGP does it (though I do not use SGP.) I use PlateSolve2, and if that fails I use a local instance of astrometry.net, and if that fails I use the online astrometry.net.
Andy
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