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M104

Messier 104
Sombrero
Spiral Galaxy
Right Ascension 12h 39m 59s Best Seen 5/1-7/15
Declination -11° 37' 23" Magnitude 8.7
Constellation Virgo

Actual		 Compared
to Milky Way
Distance ~45 million ly --
Actual Brightness -- --
Diameter ~130,000 ly ~1.3
Mass ~1.3 trillion suns ~1.3
Galactic Type Sa-Sb Sbc

What To Look For Through The Telescope

  1. Recommended eyepiece: 40mm or 80 mm.

  2. When people look through the telescope they should see a fuzzy patch of light. This is the galaxy. If they are having trouble seeing it, have them look at a star near the edge of the field, then look back to the center out of the corner of their eye.

  3. The view through the telescope will not look like photographs they may have seen. A photograph of a galaxy may have an exposure of many hours. This long exposure brings out spiral arms and other details. Our eyes allow the light to collect for only about 1/30 of a second before they refresh themselves and start over again.

M104 Information

  1. This galaxy was discovered in 1781, and independently rediscovered in 1784.

    a. Charles Messier’s original published catalog didn’t contain M104. He later added it by hand on his personal copy on May 11, 1781.

    b. Pierre Méchain mentioned his May 11, 1781 discovery of the object in a letter written two years later.

    c. William Herschel (who discovered Uranus), independently discovered it on May 9, 1784.

    d. Nicolas Camille Flammarion realized Messier’s handwritten object 104 coincided with Herschel’s discovery, and added it to the official Messier list in 1921.

  2. This galaxy is also referred to as the “Sombrero.”

  3. M104 is a member of the Virgo Cluster of galaxies.

    a. The Virgo Cluster is the closest big galaxy cluster.

    b. There are 2000 galaxies in the Virgo Cluster. There are only about 24 galaxies in our local group of galaxies.

    c. The Virgo cluster is about 40-70 million light years away,
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References
Item Updated Notes
Coordinates 2003-01-13 tweaked a bit
Magnitude 2003-01-13 sciencenet says 8.3 http://www.sciencenet.org.uk/astron/const/Virgo/m104.html SEDs says 8.0 http://messier.seds.org/m/m104.html but sciencenet does point out that brightness is spread out, so seems dimmer than star of same mag -- SO – sticking with 8.7
Distance 2003-01-13 previously said 40 million ly – BUT, SEDs says 50 http://messier.seds.org/m/m104.html and NRAO says 40 http://www.noao.edu/outreach/aop/observers/m104.html
Actual Brightness --
Diameter 2003-01-13 can find no support, but looks OK
Mass 2003-01-13 can find no support, but looks OK
Galactic Type 2003-01-13 http://messier.seds.org/m/m104.html
Other Information 2003-01-13 from http://messier.seds.org/m/m104.html Previously said Virgo cluster had 10,000 galaxies – BUT SEDs said 2000 http://messier.seds.org/more/virgo.html. Can find no support for Virgo cluster distance/diameter, but sound OK