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What's Up - M 104 in Virgo


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What’s Up

By Steve Coe

M 104 in Virgo

This bright galaxy is one of the more unique objects in the sky.  The bright core of the galaxy has a prominent ring of dark material around it.  This flat disk of material looks like a Mexican hat and therefore gives the galaxy its name—the Sombrero Galaxy.

This galaxy is one of the most massive of the nearby galaxies, about 1.3 trillion suns.  It is over 80,000 light years across and is at a distance of 40 million light years.  This puts it as an outlying member of the Virgo-Coma group.

Pierre Mechain discovered M 104 in May of 1781.  William Herschel mentioned the dark lane in his notes during a sweep with the large 20 foot telescope.  John Herschel noticed that the elongation is almost exactly east to west.

Using a 6" f/8 refractor on an excellent night about 100 miles from Phoenix lights, I saw it as bright, large and much elongated 3X1.  It is suddenly much brighter in the middle with a stellar nucleus.  The dark lane is easy and the stellar nucleus "sits on it".  This observation was with a 14mm eyepiece which gives 85X.  I rated the night as 7 out of 10 for seeing and 8 out of 10 for transparency.  All in all, a great view of a favorite.

With a 13" f/5.6 Newtonian on a night I rated the seeing at 7 and the transparency at 9, it was bright, large, very much elongated 4X1 in PA 90 and suddenly much brighter of the middle at 100X.  Again, the core "sits" on the northern edge of the dark lane.  Raising the magnification to 150X provides a nice view; averted vision doubles the size of the galaxy, both in length and width.  There is a 13th mag star to the north side, centered above the core.  The core is elongated 2X1 in the same PA as the galaxy.  At 220X there is a little scalloped detail in the edges of the dark lane.  The core area shows a small stellar nucleus about 20% of the time.  330X-no more detail seen in the dark lane, too much power, this gets rid of the galaxy to the south of the dark lane.  At lower powers there is some mottling across the face of this galaxy, but as I get to 220X and above it appears smooth.

In Tom Clark’s 42" f/4 Newtonian in New Mexico, on a night rated both seeing and transparency at 6 out of 10, this galaxy is very bright, large, very much elongated 4X1 and much brighter in the middle with an almost stellar nucleus.  The dark lane is easy and shows dark detail along its length.  In moments of good seeing that detail shows itself as viewing the dark lane as thicker and then thinner along its length.  Averted vision makes this galaxy much thicker and shows off the dark lane with more contrast.  A memorable view.


M 104 13in at 150X


M 104 by Chris Schur  12” f/5 Newtonian
From Payson, Az


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