|Double Star Section Circulars|
We have a date for the 2016 Annual Meeting: 18 June 2016.
Wondering where to find good NGC/IC data? Our Director of the Nebulae and Clusters Section, Wolfgang Steinicke, will reveal the reliable sources in his new article.
The news section contains more detailed items. I try to post items that may be of interest to members there. If you have suggestions, please contact me.
But just in case you're not regularly checking the news: The BAA Deep Sky Section Annual Meeting is on Saturday 27 February 2016. Full details are on the BAA Deep Sky Section website.
February 2015 - Picture of the Month
NGC 2237 (The Rosette Nebula) in the Constellation of Monoceros
Another nebula you might be thinking, and you'd be quite right. I've thrown in another open cluster too, NGC 2244, but there are no apologies. Being a small scope user I like the big and bold, and this image from Warren Keller and Michael Miller works just perfectly for me.
A staggering 50 light years across, it is a nursery to NGC 2244, the 'new' (1M year old) cluster of stars at center. Dark veins called Bok globules give the rose its petals. As a guitar player, it has special meaning. Stemming from the medieval lute, the beautiful decoration around a guitar's soundhole is also called a rosette. Thanks to Michael Miller for acquiring the data.
For a more detailed version, and a Hubble palette version too, please visit Warren's website: Billions and Billions.com.
James Whinfrey - Website Administrator.
Object of the Season (Winter 2015)
Quasar 3C 273 in Virgo
Quasar 3C 273 in Virgo will be announced in DSO 170, and the results will be published in DSO 172.
This image was supplied by the Hubble Space Telescope (HST). Credit: ESA/Hubble & NASA
Quasar 3C 273
Wolfgang Steinicke - Nebulae and Clusters Section Director
February 2016 - Double Star of the Month
38 Gem (06 54 38,63 +13 10 40.1) can easily be swept up since it directly follows the 3.4 mag xi Gem by a little over 2 degrees.
The current orbital period, 1898 years, as determined by Brian Mason in 2014, is clearly very uncertain but the position for 2016.0 is 143° and 7".31 in close agreement with measures by the writer late last year. The stars are of visual magnitude 4.8 and 7.8 so the quadrant in which B lies is certainly the second whilst Sissy Haas puts it in the 4th.
Admiral Smyth gives light yellow and purple, but E. J. Hartung sees yellowish and pale-orange, whilst to Sissy Haas the colours appear lemon-white and greyish.
A third, much fainter star C of mag. 11.3 can be seen at a distance of 119" whilst Andrei Tokovinin noticed a 15.0 mag dot at 151". The primary, a dwarf star of spectral class F0 is 96 light years away.
STF1121 (07 36 35.71 -14 29 00.3) is not a double or multiple star - rather it forms the bright core of the open cluster M47 in Puppis.
This cluster was discovered by the Italian astronomer Giovanni Hodierna sometime before 1654. As well as finding a dozen or so deep-sky objects before Messier catalogued them, Hodierna also compiled a small list of double stars.
The WDS contains 26 entries to cover this system and its large array of comites, but the small telescope user will easily be able to see AB (6.9, 7.3 at 300° and 6".5), whilst amongst the more obvious comites D is mag 9.5 at 72" (distance increasing), E is 9.9 at 70" (distance decreasing) and G is 7.7 at 82".
It is perhaps best seen with a pair of large binoculars. A report on the Cloudy Nights website for 2004 notes that the AB pair can be split easily with Celestron 25 x 100s. M47 and nearby M46 can be swept up in a wide-field telescope by moving 20 degrees due south of Procyon.
Bob Argyle - Double Star Section Director
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