NGC 1507 in Eridanus
December 2023 - Galaxy of the Month
With the winter clusters and nebulae season approaching I thought for this month I would try the edge on galaxy NGC 1507 in Eridanus for the GOM. NGC 1507 was first discovered by William Herschel in January 1785 and he described it as very faint.
It is classified as a barred spiral (SB(s)m pec) and if its distance is about 40 million light-years then it is a small galaxy at perhaps 45,000 light-years in diameter. It does seem a little distorted and from the colours would appear to have a lot of star formation going on, including some very large star clusters. NGC 1507 appears to have no distinct nucleus. It was included in Markarians catalogue of blue sources as Mrk 1080. If the galaxy has been distorted by a merger or interaction this would be odd as the galaxy appears to lie in a void with no other galaxies nearby. There is a nice amateur image showing its blobby nature on Gary Imm's AstroBin. Unfortunately, there does not seem to be much other research on this object.
Observationally NGC 1507 appears in the Astronomical League's Herschel II list. It does arise above the 30 degree altitude line as seen from the southern UK so should be visible but, as always with this type of galaxy, observe it when it is on or near the meridian. As it is quite small I would suggest a medium to high power when observing it.
Steve Gottlieb records it as being fairly faint with a 13.1” and the The Night Sky Observer's Guide (NSOG) Vol 1 suggests that it should be visible in 20-25cm telescopes as a faint streak. They also suggest that 30-37cm should show some sign of mottling, however I suspect that under typical UK skies this may require 40cm or more to see as most of the observations in the NSOG were made in high dry sites. Luginbuhl and Skiff (L&S) suggests that it can just be seen in 15cm, although again this was from a premium observing site. They also suggest that 30cm should show some of the condensations in the galaxy.
Owen Brazell - Galaxy Section Director
