ASTRO:
     type=Linticular spiral galaxy
     const=Virgo
     mag=8.0
     dist=31 M ly
     size=49k ly
IMAGE:
     location=EB Driveway
     BrtlCls=4
     moon=40% WnCr; sep=139°
     exposure=DSLR OSC: 60x180s (3.0h), ISO1600
EQUIPMENT:
​     optics=ES102CF APO / Hyperion 24mmEP (afocal) 1.7x, FL(eff.)=1238mm, f(eff.)/12.1
     camera=Nikon D90 (mod)
     filter=(none)
     mount=Celestron AVX
     guiding=Orion 60x240mm, ZWO ASi224MC
SOFTWARE:
     acquisition=APT, PHD2, Stellarium
     processing=DSS, Photoshop (RCAstro), LrC

The Sombrero Galaxy, also known as Messier Object 104 (or, M104) and NGC 4594 is a peculiar galaxy of unclear classification in the constellation borders of Virgo and Corvus, being about 31 M light-years from us, within the local supercluster.  It has a diameter of appx 49,000 light-years, or appx 3/10ths the size of the Milky Way. It has a bright nucleus, an unusually large central bulge, and a prominent dust lane in its outer disk, which is viewed almost edge-on.  The dark dust lane and the bulge give it the appearance of a sombrero hat.  Astronomers initially thought the halo was small and light, indicative of a spiral galaxy; but the Spitzer Space Telescope found that the dust ring was larger and more massive than previously thought, indicative of a giant elliptical galaxy. 

In the 1990s, a research group demonstrated that a supermassive black hole is present within the Sombrero Galaxy.  Using spectroscopy data from both the Canada–France–Hawaii Telescope and the Hubble Space Telescope, the group showed that the speed of revolution of the stars within the center of the galaxy could not be maintained unless a mass 1 billion times that of our Sun is present in the center.  This is among the most massive black holes measured in any nearby galaxy, and is the nearest billion-solar-mass black hole to Earth.

The Sombrero has an apparent magnitude of +8.0, making it easily visible with amateur telescopes, and is considered by some astronomers to be the galaxy with the highest absolute magnitude within a distance of 31 M light-years of the Milky Way.  Its large bulge, central supermassive black hole, and dust lane all attract the attention of both professional and amateur astronomers. 

210505 - M104 "Sombrero" galaxy