Galaxies Section

Welcome to the Galaxies Section of the Webb Deep-Sky Society. Our role is to promote visual observation and scientific imaging of galaxies by amateur astronomers.

Galaxy of the Month

Below is our current Galaxy of the Month. These are galaxies that we feel are particular worthy of your precious observing time. We have an archive of these articles that stretch back to the beginning of 2011. You can browse them, or search for specific objects and constellations in the Galaxy of the Month archives.

Your observations (sketches, images or observing notes) of any of these objects are very welcome.

For those that use observation planning software

We have plans available for all the Galaxy of the Month pieces from 2011 onwards to make it easier to find the galaxies we have covered so far.

These will be updated as new GOM’s are added.

NGC 3245 in Leo Minor

February 2018 - Galaxy of the Month

This interactive image of the NGC 3245 group was provided by the Sloan Digital Sky Survey using Aladin Sky Atlas. We also have a finder chart should help you locate these galaxies.

NGC 3245 in Leo Minor is part of a small group of galaxies catalogued as LGG 197. The group also includes the galaxies NGC 3245A, NGC 3254, NGC 3277 and NGC 3265.

NGC 3245 itself was first discovered by William Herschel in 1784 and is a mildly active galaxy of a type known as a LINER/HII transition object. NGC 3245 is classified as a lenticular galaxy and observations with the Hubble Space Telescope suggests that it contains a supermassive black hole at the centre. The mass of the black hole is probably going to be of the order of 2 x 108 solar masses.

NGC 3245 appears to form a physical pair with the superthin edge on galaxy NGC 3245A. It should be noted that the use of a letter on NGC designations normally comes from much later cataloguers, often from those using the POSS plates. In this case I believe the A designation comes from the RNGC catalogue of Sulentic and Tifft. The letter designations were also sometimes assigned in the RC2 catalogue which was published slightly later.

NGC 3245 itself may not be much of a visual challenge as it is quite bright however its companion NGC3245A I think will be and is probably going to be one for observers with larger scopes of 40cm+ aperture in a good transparent sky. NGC 3245A is also classified as a low surface brightness galaxy. Steve Gottlieb in his NGC notes suggests that with his 17.5” telescope from altitude it was an averted vison object at best.

It is not clear if the pair are tidally interacting, although GALEX images in the UV suggest there is a lot of star formation going on in NGC 3245A. NGC 3245A is also catalogued as RFGC 1796 in the revised flat galaxy catalogue. It is also listed in Alvin Huey’s Observing Flat Galaxies guide. The distance to the NGC 3245/3245A pair is of the order of 21 Mpc.

Hubble observations, particularly with the NIC (Near Infrared Camera) seem to show dust features near the nucleus of NGC 3245, which is a little unusual for a S0 galaxy. Chandra also showed that there were X-Rays coming from a small jet from the nucleus.

The other galaxies in the group are substantial distances away on the sky from NGC 3245, of the order of a degree or more so this is not a tight group of galaxies. The other galaxies in the group, with the exception of NGC 3245A, were also discovered by William Herschel, although not on the same sweeps. NGC 3254 was discovered almost a month earlier than the others.

As such they should be relatively easy targets for medium aperture telescopes, say 30cm aperture. NGC 3265 may however be a bit more challenging as it is much fainter than the others. NGC 3254 is a nice edge on spiral the others are much less interesting.

Owen Brazell - Galaxy Section Director