Galaxy of the Month in Lacerta

• NGC 7242 in Lacerta

  July 2018 - Galaxy of the Month

  In terms of deep sky observing the month of July in the UK is not dissimilar to June in terms of observing opportunities, really a time to wash the telescope mirrors and sort out any niggles before Astronomical dark returns in August.

  My target for this month is one therefore rather more of hope than expectation and is the elliptical galaxy NGC 7242 in Lacerta.

  First discovered, although not reported, by Augustine Voigt in 1862 using the Foucault 80-cm silver on glass reflector at Marseilles observatory it was actually first reported by Stephan in 1873 using the same telescope. Voigt’s observations were not actually published until 1987!

  NGC 7242 is a cD galaxy at the centre of a small group of galaxies catalogued as WBL 679, which seems to contain between 4 and 9 galaxies depending on the source used. The other galaxies in the group are NGC 7240 (discovered by Stephan in 1873), IC 1441 (discovered by Bigourdan in 1889) and UGC 11963 (Also known as IC 1591 discovered by Barnard in 1888.)

  Barnard actually found three new nebulae in this field that have been assigned the numbers IC 5191, IC 5192 and IC 5193. Unfortunately, he did not send positions to Dreyer just a drawing so it was unclear which was which and the designations were only tied down recently after historical work.

  There is another IC object here as well, IC 5195 found by Bigourdan which turns out to be a galaxy very close to NGC 7242. Barnard did not see this so it will be tough to find and require high power and steady seeing.

  For those of a historical bent the original logbooks from Lick Observatory have been digitised and are available at The Lick Observatory Historical Collections. If you are interested in Barnard’s original observation of this group it was made on the 5th Dec 1888 with the 12” refractor and the drawing is there.

  The group is going to be challenging because NGC 7242 itself is only about magnitude 13.9 and the rest are fainter, it does show however what a good observer Barnard was in that he saw six objects in this field with the 12” refractor, even though he was observing from Mt Hamilton at 4265'.

  There was a supernova in NGC 7242 in 2001 which was independently discovered by Mark Armstrong and Ron Arbour in the UK (SN 2001ib). As expected from a supernova occurring in an elliptical galaxy it was a type Ia.

  Most of the galaxies in the group are elliptical or lenticular with the exception of IC 1441 which is spiral. Even IC 5191 which looks like a spiral is actually a lenticular. The group would appear to be about 300 million light years from us.

  NGC 7240 is also catalogued as VV 1936, and IC 1952 as VV 1935, so they were thought to be disturbed systems. I suspect these may be bad classifications as I suspect that what they thought were other galaxies were actually stars near the galaxies. Even Barnard was not able to resolve the stars from the nebula when he observed IC 5192. Note that because of the vagaries of software authors some charting software may show the Barnard IC numbers and some may not.

  Luginbuhl and Skiff (L&S) suggest NGC 7242 and NGC 7240 can be seen with a 25cm telescope, but I suspect this is from altitude and at least 30-cm will be required from the UK. Probably 45-50-cm will be required to see any of the others.

  Owen Brazell - Galaxy Section Director

• August 2015 - Galaxy of the Month

  NGC 7265 in Lacerta

  This interactive image of the NGC 7265 group was provided by the Digitised Sky Survey using Aladin Sky Atlas. You can view a large overview image of the group too.

  It is not often that we think of galaxies in the small constellation of Lacerta because it lies in the Milky Way region between Cygnus and Cassiopeia. There is however a section of the constellation that lies outside the Milky Way’s boundaries and approaches the border of Pegasus and it is here that we find the galaxies.

  Our targets this month are a challenging group of galaxies associated with NGC 7265. The group is known as USGC U813. The group comprises of 8 galaxies including NGC 7264, UGC 12013 and UGC 12007, and this finder map should help you sort them out.

  NGC 7265 itself is an E/S0 galaxy with an active core. NED currently leans towards giving NGC 7265 a classification of S0 (lenticular). This type of galaxy is normally only found in galaxy clusters so it must be possible that the NGC 7265 group is or has been associated with a much larger group. The distance to the group is probably of the order of 73 Mpc. The whole group appears to be associated with the Perseus super cluster of galaxies. None of the standard references cover NGC 7265 which is slightly surprising but may give some idea of the faintness of the group. I think this is probably one for telescopes in the 40cm+ class, certainly from the UK. I am not sure the UGC galaxies will be seen from the light polluted and crud filled skies we normally expect from the UK. NGC 7265 itself was discovered by Edouard Stephan in 1876 using a 31” sliver on glass reflector whilst NGC 7264 was found by Marth using Lassell’s 48” speculum metal reflector from Malta in 1863. NGC 7263 does not appear to be part of the same group of galaxies. Steve Gottleib in his NGC notes has observed all of the NGC galaxies in this region but they are described as faint and he was observing from high clear California skies. NGC 7264 looks like a smaller version of the classic edge on NGC 4565 in Coma from the images.

  It will be interesting so see how much of this can be seen visually. It would also be interesting to see what amateur imagers can make of this group as there are no images either. I suspect that when hunting this group use a medium to high power eyepiece.

  The group of galaxies around NGC 7274 is also associated with the NGC 7265 group but interestingly also seems to be included in the poor galaxy group catalogue as WBL 681 which does not seem to include NGC 7265 as it only includes the three NGC galaxies near 7274. These three galaxies were also discovered by Stephan in 1876.

  Owen Brazell - Galaxy Section Director