Communiqué de presse

Bright Comet 1995 Q1

18 août 1995

In the evening of August 17, 1995, famous comet hunter William Bradfield (Australia) discovered his seventeenth comet. He found the comet as a 6th magnitude object with a tail longer than 1 degree in the southern constellation Crater.

A few hours later, ESO received a request for confirmation of this discovery by Brian Marsden, Director of the Central Telegram Bureau of the International Astronomical Union. In the evening of August 17, more than 20 persons at the ESO observatory at La Silla in Chile observed the new comet with binoculars. They estimated that the tail was longer than 2 degrees. They also found that they were able to see the object with the naked eye, once they knew its position. The magnitude was about 5.5.

A 10-minute exposure was immediately made with the ESO Schmidt telescope by Guido Pizarro. It showed the comet about 1 degree north of the discovery position near the horizon and with two wavy tails more than 3 degrees long. These tails are most probably ion tails, consisting of charged particles that move rapidly outward from the coma. No obvious dust tail was seen.

The Schmidt plate was scanned at La Silla and a digital file was transmitted to ESO Garching via the data link. The present photo was reproduced from this file in the morning of August 18. It shows the cometary head (coma), approximately 7 arcminutes across, as well as the beginning of the two tails that extend in SE direction.

The vertical diffuse band that crosses the comet tails is caused by a reflection in the telescope and an artificial satellite has left a nearly horizontal trail in the left half of the frame.

The comet is now moving towards the north, i.e. in the general direction of the Sun. The orbit has not yet been computed, but with this motion, there is a certain chance that it may later become a well visible object on the northern sky.

Later on August 18, further confimatory observations were obtained from New Zealand and Australia. The comet has been given the designation "1995 Q1" (see IAU Circular no. 6206 of August 18, 1995).

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