Amazing Photo of M51-Whirlpool Galaxy

  • Thread starter Drakkith
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In summary, Drakkith took fantastic photos of the Whirlpool Galaxy, Messier 51, using an Astrotech 8" Ritchey-Chrétien telescope, SBIG ST2000XM camera, and Orion Atlas EQ-G mount. He used 3 hours of exposures and had to throw out many sub exposures because of light pollution. He is hopeful that at some point he will be able to pick out a low-surface brightness galaxy located in the lower left area of the image. He also tried shooting M51 last night but did not have a tracking mount. He posted 4x45sec and 6x60sec subs at ISO 3200 ISO using his K-5 with a DA 55-300mm
  • #36
I'm using a different monitor than I normally do for my photography work (I'm in my office) and I'm noticing a lot of yellowish "flare" on my latest images of M-51 which just isn't there on my other monitors. Seeing as how the monitor I'm on now is new and has brilliant colors I'm guessing my monitor at home is a piece of junk. Does anyone else see this yellowish flare in these images?

Very nice Andy! Maybe you already mentioned it but what focal length are you using? 300-ish?
 
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  • #37
Thanks, guys- it's a 400mm focal length lens.
 
  • #38
Here's the second batch of images, two-thirds of a 'deep sky survey': Blue are Messier objects, yellow are NGC:

http://img196.imageshack.us/img196/2383/bigsky.jpg

The image size is close to twice a full 35mm frame size, call it a 2" x 3" image, covering about 8 degrees of the sky (is that the right unit? 0.0024 steradians...). I'm not sure I'll be able to get the segment including the Pinwheel galaxy before it gets too far into the light pollution- there's always next year, tho...

Some technical information- the brightest objects in these images are mag. 7 stars, the dimmest objects are around 15 magnitude- the image has a dynamic range of 8 magnitudes, or a SNR of 10^(8/2.5) = 1585 ~1600. This is an 8-bit image with a noise level is about 14 for a dynamic range of 255/14 = 18. That's what I mean when I say stacking compresses the dynamic range of images: stars from magnitude 7 - 10 are all clipped at white, the brighter stars (mag. 7, 8) are larger than the lower magnitude stars. Below 10, the stars resolve to Airy discs of uniform size (7 pixels FWHM here) and of varying brightness.
 
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  • #39
Wow Drakk that is a wicked photo(s)!

I'm shocked how clear that image is.
 
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