L. Elenin / ISON-NM Observatory

The object MG27A07 was discovered July 7th, during the course of a regular sky survey at our observatory, which became a year old on July 13th. The object’s rating (NEOR) was 100% and it was immediately placed on the NEOCP confirmation page. The speed of the new object was not high, on the order of 0.8 seconds of arc per minute, and in principle, nothing foreshadowed the discovery which eventually happened. It was necessary to continue observing.

July 8th, I again looked for this object, but didn’t see it on the images. Was it possible that the object was just an error on my part, and it didn’t really exist? Weather conditions the 7th were not the best; the object had appeared rather faint. Still, I remained certain of its existence. July 9th I again looked for the object. When I began the exposure, I saw on the NEOCP blog information that MG27A07 had been located by the American ARI Observatory (MPC code H21). Having taken my series, I also saw the object, but a little distance away from the position calculated from the observations of the first night. Later it turned out that in the new version of the program used at the observatory – CLT, error had crept in and inaccurate measurements were obtained. The calculations were done again by hand. By the way, as it came clear later, after correcting the orbit, MG27A07 was visible on several images from July 8th, but for the most part it was located on a starry background so that obtaining accurate measurements was not possible. But most important! After adding all 21 images from July 9th, the object looked like a comet! A coma was clearly visible. FWHM of the object was 5.8″, while at the same time, the average FWHM of the stars was no greater than 4.3″. This data was sent to the Central Bureau for Astronomical Telegrams, CBAT. On July 19 CBAT released a circular where the comet was assigned the designationP/2011 NO1.

Over the next several days, the cometary nature was confirmed by the ARI Observatory, and also by the 2-meter Faulkes Telescope South, FTS. I want to express my since gratitude for their work! Special thanks to all observers of T3 Project.

Preliminary orbital data say the comet is a short period comet with a period of about 13 years. At aphelion the comet goes out farther than the orbit of Saturn; at perihelion it comes in to 1.25 a.u. from the Sun and 0.38 a.u from the Earth orbit. For that reason the comet presents no danger to us. Closest approach to the Sun for this appartiion has already passed. This happened in the middle of January 2011.  Because of its small elongation and its location in the southern sky, it went unnoticed, although it might have had a maximum brightness of about 16th magnitude. Now the comet is again receding from the Sun, and by Fall its brightness will fall below 21st magnitude. The next time the comet will return toward the Sun will be in 2024, but that is a different story.

Observations continue and more details will be published soon!

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