Image Centered on Ra.09 : 55.8 (h:m) Dec.+69 : 41 (deg:m)
M 82
Irregular Galaxy M82 (NGC 3034), type Ir-II, in Ursa Major
Cigar Galaxy
Information ( from the SEDS website )
Discovered by Johann Elert
Bode in 1774.
Forming a most conspicuous physical pair with its neighbor, M81 (THE showpiece
galaxies for many Northern hemispherers), this galaxy is the prototype of an
irregular of the second type, i.e. a "disk" irregular. Its core seems to have
suffered dramatically from a semi-recent close encounter with M81, being in a
heavy starburst and displaying conspicuous dark lanes. This turbulent explosive
gas flow is also a strong source of radio noise, discovered by Henbury Brown in
1953. The radio source was first called Ursa Major A (strongest radio source in
UMa) and cataloged as 3C 231 in the Third Cambridge Catalogue of Radio Sources.
In the infrared light, M82 is the brightest galaxy in the sky; it exhibits a
so-called infrared excess (it is much brighter at infrared wavelengths than in
the visible part of the spectrum). This behaviour can also be observed for the
companion of M51, NGC 5195, and the peculiar galaxy NGC 5128 (Centaurus A). The
visual appearance is that of a silvery sliver, as John Mallas decribed it.
Recently, over 100 freshly-formed (young) globular clusters have been discovered
with the Hubble Space Telescope. Their formation is probably another effect
triggered by the encounter with M81. It was estimated that the most recent tidal
encounter occurred between about 50 and several 100 million years ago: STScI's
most recent number was 600 million years, when the 100-million-year-long period
of heavier interaction began.
As a member of the M81 group, M82 is 12 million light years distant.
M82 was discovered on December 31, 1774 by Johann Elert Bode together with M81;
he described it as a "nebulous patch", about 0.75 deg away from M81, which "is
very pale and of elongated shape," and cataloged it as No. 18 in his catalog.
Pierre Méchain independently rediscovered both galaxies as nebulous patches in
August 1779 and reported them to Charles Messier, who added them to his catalog
after his position measurement on February 9, 1781.
M82 belongs to those few Messier objects which have been assigned a Herschel
number, H IV.79, based on an observation of September 30, 1802, while William
Herschel usually carefully avoided to give his numbers to Messier objects.
William Parsons, the Third Earl of Rosse, was the first to remark on the dark
dust lanes and patches visible in the central part of M82.
Halton Arp has included M82 as No. 337 in his Catalogue of Peculiar Galaxies.
One false and one true supernova have been reported in M82 so far:
Lebofsky, Rieke, and Kailey reported the discovery of a supernova, 1986D, which
should have occurred in M82, and is e.g. listed in Kenneth Glyn Jones' book.
However, this "SN" turned out to be a false alarm. Instead, a slightly variable
2-micrometer source had fooled the discoverers.
Supernova 2004am was discovered lately on images taken at Lick Observatory on
November 21, 2003, when it was at mag 17.0.
Optics and Exposure Data
Telescope, Vixen R200ss 8 inch Newtonian at F4 (Fl 800mm) with a Televue Coma Corrector and aftermarket Moonlite accessories focuser.
Mount, Losmandy G11 with Gemini control electronics
Imager, Starlite-Xpress SXV-h9
Exposure data, Luminance = 60 minutes
Images acquired with Astroart and aligned then combined in Maxim Dl. Final RGB composite processed with Photoshop Cs
Images acquired from my backyard - " Dirt Clod Observatory" in Antelope California
