Whirlpool Galaxy M51
The "Whirlpool Galaxy," termed M51 for the 51st object in the Messier catalog, was discovered by Charles Messier in 1772.  The attached image shows the both the spiral
galaxy and its smaller irregular companion galaxy.  The interaction between the two galaxies is stretching one of the spiral arms of the Whirlpool.  M51 has been estimated
to contain 60 billion solar masses.  The light reaching my camera originated from the galaxies 15 million years ago.

The image above was obtained an a crisp cold winter night between 1 and 5 a.m., when the air was unusually steady, allowing a high resolution image.  I only needed 90
minutes of luminance exposures blended with 30 minutes each of red, green, and blue exposures to yield this result.  Source images were 5 minute exposures, unbinned for
luminance and binned 2x2 for color.  I used an ST10XME camera, Astro-physics nosepiece reducer, through a 12" Meade RC/SCT, at the dark skies of the Hidden Lake
Observatory.  Oh, what a night!

The picture is below was obtained 3 years earlier from my suburban backyard, using a combination of 64 sequential 5 minute images, for a total exposure time over 5
hours, digitally combined and then enhanced with Adobe photoshop to subtract the effects of light pollution.  I used an 8" C8 telescope with an ST10-XME camera and a
0.67x photographic reducer.  
Music:  Oh, What a Night
click on image for full size