February 2016 - Galaxy of the Month
NGC 2340 and WBL 133 in Lynx
This interactive image of the NGC 2340 was provided by the Digitised Sky Survey using Aladin Sky Atlas. You can download a finder chart for this an the surrounding galaxies too, and there's a SkyTools version as well.
This month’s galaxy of the month was a toss-up between the Abell cluster AGC 569 and the group of galaxies around NGC 2340. Both of these targets are in the constellation of the Lynx.
Although AGC 569 is an interesting target I felt that as it contains only one NGC galaxy it was going to be perhaps too much of a challenge, except for very large telescope owners.
The group around NGC 2340 however contains 9 galaxies that have been listed in either the NGC or IC catalogues. It is also classified in the WBL catalogue of poor galaxy clusters as group number 133 containing 10 galaxies so it maybe of more interest.
Unfortunately, the group is also a classic case of trying to determine which galaxy is which and even the NGC/IC project members seem to have some disagreement about who discovered which galaxy and what numbers should be assigned to them.
Perhaps the only certainty is the main galaxy NGC 2340 which was discovered by William Herschel in 1788. He may also have discovered NGC 2332 at the same time but his positions are off. What is certain is that John Herschel found it when he re-observed his father’s objects.
After this it starts to get confusing. The Birr observers using the 72” re-observed the field and found 9 objects but the observations and even more importantly the field drawings seem to be mislabelled so it is unclear which objects they actually found but it is generally accepted that they found the objects that became IC 458, 459, 461, 463, 464 and 465.
Later Kobold observed the same region with the 18” refractor at Strasbourg and found another set of galaxies in the same area. He seems to have discovered two new galaxies in IC 460 and 462 and confusingly gave the number IC 457 to the galaxy listed as NGC 2330. Unfortunately, he only published his observations quite a long time after he observed the objects and Bigourdan observing in Paris also observed the same area and reported new objects to Dreyer who tried to sort out the mess but did not get too far.
The full complex story can be found on Harold Corwin’s site at under the NGC notes section, or at least his version of it.
The group is interesting as it consists almost entirely of elliptical and lenticular galaxies, although the classifications of some of the galaxies may be uncertain because they are faint and have not been studied in much detail.
My suspicion is that the NGC galaxies as identified should be visible in medium sized telescopes but the IC galaxies may require larger apertures to see.
I will be interested in hearing what can be seen.
Owen Brazell - Galaxy Section Director
And a few of our members have provided observations for this field.