Object Information:                 M81 (NGC 3031)  Bode's Nebula,
                                               Mag. - 6.9
                                               Constellation - Ursa Major
                                               Location - R.A. 09:55.6,  Dec. +69.04
                                               Distance -  10 million light years,
                                               Size -  70,000 light years across,

Object Notes:    M81 is a spiral galaxy with the morphological classification of SA(s)ab I-II.  This means that this  galaxy is classified as a non-barred spiral type [SA], with an "s" shaped structure [s], fairly tightly wound spiral arms [ab] that are moderately well developed [I-II].

      M81 is located in the Messier 81 Galaxy group, the center of which is located about 10 million light years away.  The Messier 81 Galaxy Group is the second closest galaxy group to our own Local Group.  The nearest to us is the Sculptor Group, only 8 million light years away.  The absolute magnitude of M81 is estimated to be -20.8, a luminosity of 17 billion suns.

    M81 was discovered by J.E. Bode of Berlin in December 1774.  Charles Messier added this object to his now famous catalogue in February 1781.  This object is also commonly referred to as "Bode's Nebula" after its discoverer.  It was not until the 20th Century that astronomers realized that the myriad of faint "nebulosity" surrounding us are actually galaxies separate and apart from our own.

Imaged at:                               San Diego Astronomy Association site near Tierra del Sol, San Diego County, California,
                                               Elevation - 4000 feet

Equipment:                              Optics - Takahashi MT-160 Newtonian at f/6.3
                                               Mount - Losmandy G-11,
                                               Camera - Santa Barbara Instrument Group (SBIG) ST-7  CCD,
                                               Focal Reducer/Field Flattener - none,

Exposure Information:             November 24, 2001
                                               Sum of four 900 second images,
                                               High Resolution Mode, guided with a SBIG STV

Image Acquisition Software:    CCD Ops for DOS,

Image Processing Software:     MIRA AP 6  - Image registration and combination; AIP for Windows -image calibration; Photoshop 6.01 final processing for web publication.

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All the images in this site are © Copyright 2002 by Dean Jacobsen.
Any use of these images without the prior written consent or knowledge of the author is strictly prohibited.
Contact Dean at deanjacobsen@adelphia.net for more information.