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Observing Sombrero Galaxy (M104)

The Sombrero Galaxy is a peculiar galaxy of unclear classification in the constellation borders of Virgo and Corvus, being about 9.55 megaparsecs from the Milky Way galaxy. It is a member of the Virgo II Groups, a series of galaxies and galaxy clusters strung out from the southern edge of the Virgo Supercluster.

What Sombrero Galaxy is

The Sombrero Galaxy is a peculiar galaxy of unclear classification in the constellation borders of Virgo and Corvus, being about 9.55 megaparsecs from the Milky Way galaxy. It is a member of the Virgo II Groups, a series of galaxies and galaxy clusters strung out from the southern edge of the Virgo Supercluster. It has an isophotal diameter of approximately 29.09 to 32.32 kiloparsecs, making it slightly larger than the Milky Way.

How to observe it

This is a fainter target that rewards aperture and dark skies. A 150 mm or larger telescope from a site away from town lights shows it best, and averted vision helps.

It lies in the constellation Virgo. To find it, learn the constellation first, then star-hop from its brighter stars with a finder or a wide-field eyepiece before switching to more magnification.

Magnification is your telescope's focal length divided by your eyepiece's focal length. For an extended object like this, start low to frame it, then step up in power only if the object takes it. Use the Fit My Telescope tool to see the exact magnification, true field and exit pupil each of your eyepieces gives.

How it looks at the eyepiece

What you see at the eyepiece is fainter and less colourful than a photograph, because the eye takes in light in an instant while a camera builds it up over minutes. Expect a grey glow rather than the vivid colours of an image, and let your eyes dark-adapt for at least twenty minutes to see the most.

Frame it at low to medium power first with a wide true field, then step up the magnification only if the object stays sharp and the sky is steady. The Fit My Telescope tool shows the magnification, true field of view and exit pupil each of your eyepieces gives in your telescope, so you can pick the one that frames the object best.

The object in NASA imagery

NASA has imaged this object. One example in the NASA Image and Video Library is titled The Sombrero Galaxy Split Personality, from JPL.

This infrared vision of NASA Spitzer Space Telescope has revealed that the Sombrero galaxy, named after its appearance in visible light to a wide-brimmed hat, is in fact two galaxies in one.

NASA imagery is in the public domain. What you see through an eyepiece is fainter and mostly grey, since the eye does not accumulate light the way a long-exposure camera does, but knowing an object's true shape helps you recognise it at the telescope.

PropertyValue
Object typeedge-on galaxy
ConstellationVirgo
Apparent magnitude8.0
CatalogueMessier 104 (M104)

Object data from Wikidata (CC0) and standard Messier catalogues.

Related

Sources: Sombrero Galaxy (Wikipedia, CC BY-SA) · Wikidata (CC0) · NASA Image and Video Library: PIA15426 (public domain)