ST-10XME and CFW8a, Astrodon LRGB filter set
Takahashi FSQ F/5 Fluorite Refractor w Robofocus
20 x 3 min Luminance, 8 x 5 min RGB for a total of 3 hours
Self-guided on an AP900QMD mount
Acquired, Flats and Darks subtracted in CCDSoft5
Alignment and Sigma Reject combine in Maxim
Levels and curves in PS CS2
Sharpening via High Pass filter on the Luminance in PS CS2
Luminance layered in per Rob Gendler's article
No noise reduction
RA: 1h 33.9
Dec: 30:39
Visual Mag: 5.7
73 x 45 arcminutes
Click on the image to see it at 2x this size.
===============
From SEDS.ORG:
Probably discovered by Hodierna before 1654. Independently discovered by Charles Messier
1764.
The Triangulum galaxy M33 is another prominent member of the Local Group of galaxies. This
galaxy is small compared to its big apparent neighbor, the Andromeda galaxy M31, and to our
Milky Way galaxy, but this is more of an average size for spiral galaxies in the universe.
One of the small Local Group member galaxies, LGS 3, is possibly a satellite of M33, which
itself may be a remote but gravitationally bound companion of the Andromeda galaxy M31.
M33 is approaching us (our Solar System) at 182 km/s. Corrected for our motion around the
Milky Way's Galactic Center, it is approaching our Galaxy at 24 km/sec.
M33 was among the first "spiral Nebulae" identified as such by William Parsons, the Third
Earl of Rosse. It was also among the first "nebulae" identified as galaxies, in which
Cepheid variable stars were found; Edwin Hubble published a fundamental study in 1926
(Hubble 1926).
The results of the Hipparcos satellite have lead to a revision of the cosmic distance
scale, therefore also of our distance to M33: The current value is about 3.0 million light
-years. With this value, its angular dimension of 73 arc minutes in major axis (about 2.5
times the Moon's diameter) corresponds to about 50,000 light-years, half the diameter of
the Milky Way. However, the faintest outlayers seem to reach more far out, so that the true
diameter may be at least 60,000 light-years. The mass of the Triangulum Galaxy has been
estimated between 10 and 40 billion solar masses.
For the observer, this galaxy can be glanced with the naked eye under exceptionally good
conditions; for most people, it is the most distant object visible to the naked eye. It is
outstanding in good binoculars, but as its considerable total brightness is distributed
quite evenly over an area of nearly four times that covered by the full Moon, its surface
brightness is extremely low. Therefore, it is difficult to impossible to view this galaxy
in telescopes which do not allow low magnification - lowest is best for this object ! M33
is also a most rewarding target for the astrophotographer, who can track down its spiral
arms and brighter nebulae with considerably inexpensive equipment.
===============
Flesherton, Ontario
August 20 2006
图文来源：http://www.astrofoto.ca/stuartheggie/ccd_photos/M33_LRGB_FSQ.html |
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