Barred Spiral Galaxy NGC 2903 in Leo

Barred Spiral Galaxy NGC 2903
A 20 minute exposure with an SBIG ST-9E CCD camera taken thru our 20 inch F/8.1 telescope. The image below is a color version.

Color Version - Barred Spiral Galaxy NGC 2903

Barred Spiral Galaxy NGC 2903 (and NGC 2905):

Dreyer's description in the New General Catalog (NGC):

"Considerably bright, very large, extended, gradually much brighter middle, resolvable, but mottled, southwest of 2."

NGC 2903 is a Barred Spiral Galaxy in the Constellation of Leo. NGC 2905 is the northeast arm of NGC 2903. John Herschel (1792-1871) recorded several observations of it in that position, as well as a sketch. The only slight mystery is why William Herschel (1738-1822) made NGC 2905 one of his first class nebulae, ranking it in brightness with the central portion of NGC 2903 itself.

The internal pattern of dust in this nearly face-on galaxy is quite intricate. The delicate dust filaments threading across luminous regions are lost at points, but there is no question that these patterns are present. The nucleus is composed of about eight intense knots, presumed to be giant HII regions. The Hubble Space Telescope Near Infrared Camera image of the nucleus shows many clusters of bright new stars.

Based on the published red shift, (and a Hubble Constant of 62 Km/sec per Mpc) a rough distance estimate for NGC 2903 is 29 million light years, with a diameter of about 107,500 light years.

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George Normandin, KAS

May 26th, 2001