M 109 Galaxy Click on photo to return to 'Galaxies' Home
M 109 NGC3992
Dreyer description: Considerably bright, very large, westward moderately extended, abruptly brighter middle bright resolvable, but mottled nucleus; = M109.
RA: 11h 57m 36.2s Dec: +53°22'31" (Epoch 2000)
Azm: 49°54'37" Alt: +45°45'59"
Always above horizon. Transit: 19:01
Size: 7.7' x 4.7'
Discovered by Pierre Méchain in 1781.
M109 is one of the "Theta"-like barred spirals, which appears as a "hazy spot" situated just 40' SE of the mag 2.44 star Gamma Ursae Majoris (Phad, or Phecda).
M109 is about 7-by-4 arc minutes in angular extent, and of apparent visual magnitude 9.5 or 9.6. Visually, only its bright central region together with the bar can be seen, and appear pear-shaped in smaller telescopes, "with a strong suspicion of a granular texture" (Mallas).
According to Brent Tully's Nearby Galaxies Catalog, M109 is about 55 million light years distant, as it is receding at 1142 km/sec, and a member of the Ursa Major Cloud, a giant but loose agglomeration of galaxies. Tully took individual distances from the redshift in a model taking the Virgo-centric flow into account. The distance of this galaxy, however, may be a bit smaller, as the average recession in this cloud is lower, and some part of the surplus may be peculiar velocity.
The type I supernova 1956A occured in this galaxy on March 17, 1956, and reached 12.8 mag (or up to 12.3, according to some sources) in its maximum.
16" F/4.87 Newtonian , ST-8XE, CFW8 06/20/04 Temp. = -13.5 C
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