Popular Astronomy

Share to Facebook Share to Twitter Stumble It More...

October 2010

The latter half of October 2010 saw a series of lunar occultation events which were observed successfully by members of the Section, and my thanks to all those who submitted reports.

STF2752, Zeta & Tau Arietis

Mike Clarke (Retford, Nottinghamshire) watched and timed the disappearance of three events, starting with the double star STF2752 on 16 October 2010. Using a 102mm f/8 telescope between 91x and 200x magnification, Mike reported: “Rather poor seeing conditions; however the double nature of the magnitude +7.2 star STF2752 was visible at high magnification in the eyepiece of the 102mm refractor. The dark limb disappearance was timed at 21h 28m 14s UT. The primary star was occulted first, quickly followed by the magnitude +9.9 companion star.” A further report from Mike followed, for the observation of zeta and tau Arietis, on the 24 and 25 October, and he submitted two superbly detailed digital images; one showing tau Arietis shortly after reappearance, and the other showing zeta Arietis as it approached the bright limb of the Moon. Mike was also successful in observing the reappearance of zeta Arietis.

3 Geminorum

Colin James Watling (Kessingland, Suffolk), timed the reappearance of 3 Geminorum on 27 October 2010, using a 20×60 Russian mounted binocular, at 23h 00m 59s UT.

Mike Feist (Portslade, Sussex) also attempted to observe the reappearance of 3 Geminorum, and reported: “I went outside with my recently acquired 50mm spotting scope (a Vanguard SF-531T set at 22x magnification) to look at the Moon. A nice view, with the terminator running from Burg and Lacus Mortis, three tiny peaks in the approaching sunset, up the Serpentine Ridge to a couple of bright peaks in the darkness. I noticed a reddish star on the other side of the field of view (about 1.5 degrees), and identified this star as eta Geminorum. I then had a go at looking for the reappearance of the fainter star 3 Geminorum. It was a bit difficult, due to murky sky conditions, but I did find it at 23h 01m UT, shortly after it had reappeared.

Tejat Posterior

An early morning event took place on Thursday 28 October, and involved the reappearance of the star Tejat Posterior (mu Geminorum). Jeff Stevens (Stoke-on-Trent) was successful in observing this spectacular event, using an 8” reflector at 46x magnification. Tejat Posterior is a magnitude +2.9 star, which lies at the foot of Castor, one of the twins in the constellation of Gemini. The orange colouration of this star, along with its relative brightness, made for a stunning reappearance from behind the dark limb of a waxing gibbous Moon. Jeff timed the reappearance at 05h 54m 49.18s UT, from his location in Stoke-on-Trent, and managed to capture several images of the star several minutes after the initial reappearance.

Mike Feist also attempted the Tejat Posterior event, and reported: “I got up at 04h 16m UT, and going outside with the 50mm spotting scope, I saw that there was much high cirrus cloud, through which the Moonlight produced a 22 degree halo that had Castor, Pollux, Procyon, Betelgeuse and Bellatrix just enclosed within it. Details on the Moon, along with the star Tejat Posterior, were visible in the scope, although this time they were separated by a considerable distance; perhaps equal to the apparent length of the Lunar Apennines by 04h 47m UT. However, after 04h 58m UT, lower fast moving cloud blocked the star from view. By 05h 21m UT, a gap enabled a clear view of the limb, in which there was a noticeable ‘dent’, and I saw the star against the Moon for a very short while.

Added by: