sponsored by psychohistorian.org


Deep Sky Observer's Companion – the online database


Welcome, guest!

If you've already registered, please log in,

or register an observer profile for added functionality.


log in to manage your observing lists























Full database:

Entire DOCdb database of 18,816 objects.



NGC 3556 (7,571 of 18,816)


oc gc pln bn dn gx gxcl ast aka lost




finder chart

altitude today

altitude (year)


½°, , in DOCdb

Warning: date(): It is not safe to rely on the system's timezone settings. You are *required* to use the date.timezone setting or the date_default_timezone_set() function. In case you used any of those methods and you are still getting this warning, you most likely misspelled the timezone identifier. We selected the timezone 'UTC' for now, but please set date.timezone to select your timezone. in /home/yivumoo/public_html/show_object.php on line 167

show browsing

Messier 108

NGC 3556, LEDA 34030, MCG+09-18-098, UGC 6225, Messier 108, V 46, h 831, GC 2318

RA: 11h 11m 31.29s
Dec: +55° 40′ 31″

Con: Ursa Major
Ch: MSA:576, U2:46, SA:2


(reference key)

Type: galaxy, Sc

Mag: B=10.7, V=?

Size: 8.128′ x 2.754′
PA: 80°

Historical observations

William Herschel (c.1784)

Synonyms: H V-046

Recorded on APril 17, 1789 by William Herschel with an 18.7-inch f/13 speculum telescope. He called it "vB, mE, resolvable, 10' long, 2' broad. There is an unconnected pretty bright star in the middle."

Published comments


A supernova erupted in this galaxy in 1969 (13.5p)

Sulentic & Tifft (1973)

The RNGC (Sulentic and Tifft 1973) notes that this is a 11.0 mag galaxy. Their coded description reads EL,HISB,KNPCHYDSKSTR.

Doig, P. (1925)

Doig, P. (1925) Notes on the nebulae and clusters in Webb's 'Celestial Objects for Common Telescopes' (Sixth edition, Vol.ii). Part V. M.N.R.A.S., 36(3), 89.

Sandage, A. (1961) The Hubble Atlas of Galaxies

This galaxy appears on page 35 of "The Hubble Atlas of Galaxies" by Allan Sandage (1961, Washington, DC).

Modern observations

Walter Scott Houston

Houston writes: "Although Messier did not include this object in his original 18th century catalogue, handwritten notes in his personal copy of the work make it clear he was aware of it ... it is a narrow streak about 7' long with a small central condensation."

Tom Lorenzin

Tom Lorenzin, in the electronic version of "1000+ The Amateur Astronomers' Field Guide to Deep Sky Observing", notes: "10M; 8' x 2' extent; very large and bright, E-W-oriented gash; somewhat mottled appearance; 12.5M star superimposed off-center; see photo at HAG-35; 50' NW of M-97; !good supernova prospect!."

Contemporary observations

Tom Bryant

2012 1 28 23:30:55

Observing site: Little Tycho Observatory

Telescope: C-8

[11h 11m 30s, 55 40m 0s] AKA M 108. An almost starlike nucleus, surrounded by a faint, elliptical haze in pa 80. The "nucleus" is actually a foreground star, as shown in a U of Arizona 4 meter image.

Favourite lists

Lacaille's catalogue

The Messier objects

Dunlop's catalogue

The Bennett objects

The Caldwell list

Named DSOs

Object search

First search phrase


Second search phrase

Type of object to include:

open cluster
globular cluster
planetary nebula
bright nebula
dark nebula
galaxy cluster
asterism & stars

The Bug Report

DOCdb is still in beta-release.

Known issues, feature requests, and updates on bug fixes, are here:

> Bug Report


Found a bug? Have a comment or suggestion to improve DOCdb? Please let us know!

> Contact us


DOCdb is a free online resource that exists to promote deep sky observing.

You could help by sharing your observations, writing an article, digitizing and proof-reading historical material, and more.

> Find out more

Everything on DOCdb.net is © 2004-2010 by Auke Slotegraaf, unless stated otherwise or if you can prove you have divine permission to use it. Before using material published here, please consult the Creative Commons Attribution-Non-Commercial-Share Alike 2.5 License. Some material on DOCdb is copyright the individual authors. If in doubt, don't reproduce. And that goes for having children, too. Please note that the recommended browser for DOCdb is Firefox 3.x. You may also get good results with K-Meleon. Good luck if you're using IE. A successful experience with other browsers, including Opera and Safari, may vary.