Comet 1999 Y1 LINEAR

Comet 1999 Y1 LINEAR reached magnitude 11.7 during October 2000. This made it a relatively easy object for southern observers with 10" or larger telescopes. With a perihelion of over 3AU, the comet remained visible for a considerable length of time, with the final visual observations being made as late as October 2001. I imaged the comet twice during June 2001. At that time, the comet was around 13th magnitude and showed a strong central condensation with a faint outer coma and a hint of a tail.


Comet 1999 Y1 LINEAR. June 19, 2001.
Combination of 2, 3 minute exposures, Meade 416xt CCD. 300mm f/6 newtonian at prime focus.

The comet shows a 'bright' central condensation with a faint outer coma. A very faint tail can just be made out heading towards the top of the image. At this stage the comet was around 13.6 magnitude but was not visually observable in a 12" telescope.


Comet 1999 Y1 LINEAR. June 20, 2001.
Combination of 2, 3 minute exposures, Meade 416xt CCD. 300mm f/6 newtonian at prime focus.

At this stage the comet was passing through Cetus in a region containing numerous faint galaxies, not far from the galaxy cluster AGC 128. However none of the galaxies visible in this image are listed in MegaStar or The Sky.

Before leaving 2000, mention must be made of a very interesting comet, 1999 S4 LINEAR. Discovered on September 27, 1999, this comet was expected to put on a fine display as it passed through perihelion. Leading up to perihelion the comet was visible only in the northern hemisphere and southern observers read reports of the comet reaching 6th magnitude, so we were all looking forward to when it headed south. However just when the comet was starting to become visible it disintegrated! The Hubble Space telescope was able to obtain some spectacular images of the disintegration, such as the example below.


While the disintegration was a wonderful event for comet scientists, southern observers felt cheated in missing out on a bright comet! At least we did not have to wait too long for the next one!