Messier 100 (NGC 4321) and Surrounding Galaxies
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 it? More
information about M100 may be found here, and on Rob Gendler's
Date: April 20, 2006.
FS-102 at f8 , on the G11 Losmandy
Autoguider: SBIG STV with
Camera: Maxcam CM10
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.
Post-processing: 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
note: Graphics on this website
may not be reproduced without author permission.
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