Object Information:               M109 (NGC 3992),
                                             Visual magnitude  -  9.8,
                                             Galaxy Type - SB(rs)bc,
                                             Constellation -  Ursa Major,
                                             Location -  R.A. 11:57.6, Dec. 53:23,
                                             Distance -  approximately 46 million light years distant,
                                             Size -  In excess of 100,000 light years across.

Description:    Although mentioned By Charles Messier in his March 24, 1781 observations of M97, this object was not included in Messier's original published list of 103 objects.  M109 was only added to the official Messier listing of objects in 1953 by Owen Gingerich.  This barred spiral galaxy is classified according to the Hubble system as a SB(rs)bc, which means that this object features a central bar (SB), with an inner ring (r), an "s-shaped" overall structure (s), and with moderately loosely wound spiral arms (bc).

This member of the Ursa Major Galaxy Cluster is a very nice example of a barred spiral.  The central bar and detail of the spiral arms are clearly seen in this accumulated exposure of 45 minutes. 

Imaged at:                             Vallecitos County Park, Anza-Borrego Desert, San Diego County, California;
                                             Elevation - 1,500 feet

Equipment:                            Optics - Takahashi MT-160 6.25" classical Newtonian at f/6.3
                                             Mount - Losmandy G-11 with SkyWalker Servo drive system,
                                             Camera - Santa Barbara Instrument Group (SBIG) ST-7E NABG  CCD,
                                             Focal Reducer/Field Flattener - none,
                                             Filter - none,

Exposure Information:            March 2, 2003
                                             Sum of three, 900 second exposures for a total exposure of 45 min.,
                                             High Resolution Mode,

Image Processing Software:   AIP for Windows - image calibration, MIRA AP 6.03 - Image registration, Photoshop 7 - final processing for web publication.