Messier 100 (NGC 4321) and Surrounding Galaxies

All Images Copyright Steve Cannistra

Please click here or on image for a higher resolution view.

Magnitude:  9.3
Size: about 7' x 6'
Distance: 56 million light years
RA: 12h 22.9m
Dec: +15 degrees 49'

M100 was discovered by Pierre Mechain in 1781 and subsequently catalogued by Charles Messier later that year.  It is the brightest member of the Virgo Cluster of Galaxies and, along with M51, was one of the first galaxies observed by Lord Rosse to have a spiral structure.  There are about 20 Cepheid Variables in M100, which have been used to great advantage in determining its distance from us.  M100 is a Grand Design galaxy, which refers to the prominent spiral arms containing islands of new star formation.  It is thought that new star formation in Grand Design spirals like M100 and M51 is partly due to gravitational interaction with neighboring galaxies.   As an added bonus, a keen eye can see the waning signal from Supernova SN2006X, a type Ia supernova discovered in early February 2006.  Can you find itMore information about M100 may be found here, and on Rob Gendler's website.

Photographic Details:

Date:  April 20, 2006.
Takahashi FS-102 at f8 , on the G11 Losmandy Mount. 
Autoguider:  SBIG STV with e-finder.
Camera:  Maxcam CM10
Astronomik Type II R, G, B, plus clear filter set; IDAS LPS.
Exposures:  L:R:G:B (140, 20, 35, 35 minutes, unbinned);  Total exposure duration 3.8 hours.
Conditions:  Temperature 50 degrees F; good transparency; poor seeing.  I had a little trouble with tracking (I need to recheck balance for f8 configuration) and had to discard several color subs, which almost never happens.  Still managed a decent color signal.
Debloomed with Ron Wodaski's Debloomer software, calibrated and aligned in Maxim, combined using RC Sigma Reject MaximDL, followed by DDP in ImagesPlus (IP).  Levels, curves, high-pass sharpening in Photoshop CS (16 bit format).

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