M51 (Whirlpool Galaxy) and NGC 5195
Characteristics:
Magnitude: 8.4
Size: about 11' x 7'
Distance: 37 million light years
RA: 13h 30m 5.9s
Dec: 47 degrees 10' 04"
Description:
The famous face-on spiral galaxy M51
(NGC 5194) is located in the constellation Canes Venatici (Hunting
Dogs). It
was originally discovered by Charles Messier in 1773, although its true
spiral
structure was first realized by Lord Rosse
in 1845. The galaxy has a characteristic shape, in the form of an
inverted question mark, due to its association with another galaxy
located well behind M51 in the above photograph, known as NGC
5195. Note that this
smaller galaxy is seen edge on and is partly obscured by a long, thin,
prominent dust lane extending from M51. Interaction between M51
and NGC5195 is thought to trigger new star formation in M51 itself, as
represented by clusters of young, blue stars within the spiral
arms. M51 is a good target
for visual observation through small aperture telescopes in dark skies,
although it can be a challenging to discern its spiral structure in
more light polluted skies. Closer examination
of
this image reveals several other small galaxies, including IC4263,
IC4277, and IC4278. More
information
about M51
may be found here.
Photographic Details:
Date: March 18, 2006 and April 15, 2006.
Scope: Takahashi
FS-102 at f8 , on the G11 Losmandy
Mount.
Autoguider: SBIG STV with
e-finder.
Camera: CM10
Filter: Astronomik
Type II R, G, B, plus clear filter set; IDAS LPS.
Exposures: L:R:G:B. 18 x
10' subexposures for total 3 hours of luminance, unbinned; 45' each for
R, G, and B, unbinned. Total exposure duration 5.25 hours.
Conditions: Temperature 50 degrees F; average
transparency; average seeing; a few passing clouds.
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
bit format).
Please
note: Graphics on this website
may not be reproduced without author permission.
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