Astronomy & Space | Comet Ison

Hello and welcome to Astronomy & Space. In our next program on July 31st we take a look at the highlights of the August Night Sky and the Perseid meteor shower.Our main theme is Comets, what are they and where do they come from.We also have the latest news and photographs of Comet S1 2012 ISON which is scheduled to reach magnitude –4.9 on 28th November.

On Sep. 21, 2012 Vitali Nevski (Belarus) and Artyom Novichonok (Russia) discovered an asteroidal object of magnitude 18.5 in images taken with the 0.4m telescope of the International Scientific Optical Network (ISON). Although they suspected a comet, due to its motion, they did not mention anything in their discovery report. Thus, after the object appeared on the NEOCP page, other observers first noted and reported the cometary nature. In consequence the comet was given the project's name. Comet C/2012 S1 (ISON) displayed a 9" coma and a faint tail in p.a. 280°. The central condensation seemed elongated. Shortly thereafter the comet was identified on images taken on Dec. 28, 2011 and Jan. 28, 2012, which allowed the quick determination of accurate orbital parameters. Accordingly this comet will come extremely close to the Sun on Nov. 28, 2013 (0.012 AU). Since the discovery brightness indicates an intrinsically bright object, the comet could become very spectacular (CBET 3238). Assuming an average brightness evolution (n=4) the comet should reach magnitude -10 at perihelion, with the visual tail stretching about 40-50° during the following days. After perihelion the comet will move strictly northward, thereby approaching Earth. It will come within 0.43 AU of our planet on Dec. 27, when it could still be as bright as 4 mag, with a coma the size of the Moon. On Jan. 7/8, 2014 it will pass the northern celestial pole at a distance of only 3°. In case it should be a new comet (n=3), the predicted values are -5 mag / 8° / 6 mag / 7.5 mag