Galaxy of the Month Archive 2026

In this series of articles we draw your attention to galaxies particularly worthly of an observer's time.

• NGC 936 in Cetus

  January 2026 - Galaxy of the Month

  First discovered in 1785 by William Herschel the galaxy pair NGC 936 and NGC 941 in Cetus are an interesting combination of galaxy types.

  William Herschel actually thought NGC 936 was a planetary nebula because of its shape and classed it in his Class IV objects. NGC 936 is actually a lenticular galaxy with a bar and shells whose shape has given it the name of the Tie Fighter or Darth Vader galaxy. There is a nice image of the galaxy taken by the VLT. NGC 941 is an open spiral galaxy classed as a Wolf-Rayet galaxy because its spectra reflects that of hot young stars.

  If you compare images of the pair in the ultraviolet taken by the GALEX satellite, NGC 941 shows up as a large bright galaxy and NGC 936 hardly registers at all because there is no star formation going on in it. NGC 936 and 941 do not seem to be interacting. They also appear to be part of a small group of galaxies (LGG 60) which contains maybe 7 galaxies, including NGC 955. The group is associated with the M77 galaxy group. The distance to them is somewhat uncertain but NGC 936 appears to lie at a distance of perhaps 21 Mpc. Colour images show the differences between the stellar populations of the two galaxies as NGC 936 is yellowish as it consists mainly of old stars whereas NGC 941 is blue from all the young stars forming in it.

  Historically NGC 941 is interesting because it was one of the galaxies that Halton Arp claimed was associated with high redshift quasars and this indicated they were ejected from the galaxy, a theory that has since been discredited.

  The bar in NGC 936 is particularly pronounced but it is still not clear if the galaxy and its shape is influenced by a massive dark matter halo. NGC 936 was also home to the type Ia supernova SN2003gs, probably one of last supernovae to be discovered visually by Robert Evans using a 30cm telescope.

  NGC 936 makes it into Stephen O’Meara’s The Secret Deep list as number 7.

  Visually small telescopes in the range 20-22cm will show the core of NGC 936 but it will take larger apertures to see much of the detail that gives rise to its name. NGC 941 is going to be much more difficult to see and will show as just a faint irregular patch.

  NGC 936 and NGC 941 are close enough together that they can be seen in the same field of view using a medium power wide field eyepiece. Steve Gottlieb suggests that both the NGC galaxies are visible in 20cm although they are better seen at 35cm.

  Unfortunately, from the UK the pair do not rise much above the two airmass line so, although they can be seen with telescopes in the 20-22cm range from southern climes, I think that 30cm will be required from the UK.

  Owners of large aperture telescopes may be able to pick up UGC 1945 which makes an equilateral triangle with NGC 936 and NGC 941 in the same field. It is much fainter at around 14th magnitude. UGC 1945 is actually physically associated with the other two. There is a nice amateur image of the group on astrobin.

  Owen Brazell - Galaxy Section Director

  If you'd like to try out the Clear Skies Observing Guides (CSOG), you can download observing guide for the current Galaxy of the Month without the need to register. CSOG are not associated with the Webb Deep-Sky Society but the work of Victor van Wulfen.