Thursday, May 29, 2014

Comet 67P Churyumov-Gerasimenko - First amateur images 2014

As the European Space Agency's Rosetta Mission ramps up in a busy week of astronomy, Observatory W96 and Observers A. Maury, J.-G Bosch, J.-F. Soulier were the first amateurs to report positions of 69P (this apparition) to the MPC. Amateur images of Comet 67P have also been acquired by the Professional-Amateur Collaboration in Astronomy (PACA) for comet 67P led by Dr Padma Yanamandra-Fisher in partnership with Amateur Astronmers. The PACA group uses social media to connect amateur and professional astronomers to provide observation follow-up, monitoring and collaboration on science missions.

Comet 67P is about to be visited by the Rosetta Probe and ESA released their first photos, 2 weeks ago, of the comet starting to come to life as it heads on in towards the sun. The Rosetta mission is to follow the comet round the sun during the part of its orbit where the ices and dusts begin to discharge and form the tail. In november 2014, Rosetta will deliver a landed named Philae that will touch down on the nucleus of the comet to sample the particles as they become active.

Pictured here at a very faint magnitude 21.2 you can see Comet 67P, and the position of the Rosetta spacecraft is also marked (even though it is way too faint to see). ESA this week began a number of engine burns to slow the spacecraft as it approaches the comet.

The star field is quite crowded, and one of the most interesting parts of the video is the amount of "traffic" in this part of the sky. There were about 6 clearly identifiable asteroids in the full field of view, I have labelled a couple of the closer ones for reference. One asteroid in the field of view caught my eye as it seemed to dip in brightness, so it has been noted for further follow up as it approaches opposition in July.

Capturing the comet at such a faint magnitude required a deep "stacking" of images to account for the movement of the comet. "Stacking" is a process used to add a number of images together to improve the signal to noise ratio of the target. The comet was travelling so slowly relative to our point of view that I was able to resolve it with 12x300 second images. These images were then stacked in three groups of 4 at the movement of the comet - 0.16arc"/min at a position angle of 226 degrees. My images were quickly followed up by Rolando Ligustri, Bacci Paolo Backman. The astrometry (positional information) was included in MPEC 2014-K54

Previously in 2012, amateurs using the the Faulkes Telescopes had photographed 67P at aphelion (its furtherest point from the sun), also a remarkable effort!. In January 2014 the large telescopes in Chile, European Southern Observatory (ESO) and the Very Large Telescope (VLT) recovered 67P and have been following it regularly, this was the first occasion that amateurs had obtained images on this apparition.

For more information about the program check out the Year of Southern Comets article at PACA has a Facebook and Flikr group for members and a website under construction, it is open to any amateur astronomers who have their own telescope, are familiar with photometry and astrometry, are members of, or have access to other telescope facilities and are prepared to work as a team on the science effort.

The Rosetta Spacecraft was named after the Rosetta Stone which assisted historians and archeologists decipher the Egyptian hieroglyphs, scientists hope that in the same way the data gathered will assist in our understanding of the early solar system.


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