Comet West (C/1975 V1)

Discovered by:        Richard M. West
Discovery date:       August 10, 1975
Peak magnitude:    -3.0

Aphelion:                 70,000 AU (10,470 billion kms or 6,500 billion miles or 1.1 light-years)
Perihelion:               0.197 AU (29.47 million kilometres or 18.31 million miles)
Semi-major axis:      35,000 AU (5,235 billion kilometres or 3,250 billion miles)
Eccentricity:            0.99997
Orbital period:          unknown maybe as large as 6 million years
Inclination:               43.1 degrees

Last perihelion:        February 25, 1976
Next perihelion:       unknown

Comet West photographed in March 1976 (J. Linder/ESO)

Discovered photographically on August 10, 1975 by Richard M. West of the European Southern Observatory.

At the time, Comet West was at magnitude 14, had a small dust tail and was located 2.98 AU from the Sun (beyond the orbit of Mars).

Passed perihelion on February 25, 1976.

The comet nucleus was observed to split into four fragments as it passed by the Sun. At the time this was one of very few comet breakups observed, the most notable previous example being the Great Comet of 1882. More recently, comets Schwassmann-Wachmann-3 (73/P), C/1999 S4 LINEAR, 57/P du Toit-Neujmin-Delporte and ISON (C/2012 S1) have all been observed to disintegrate during their passage close to the Sun.

Peak magnitude was -3 and bright enough to be visible during daylight for a couple of days. This was much brighter than originally predicted with Comet West exceeding expectations.

Although a spectacular object before sunrise in March 1976, Comet West received very little media coverage. This was partly due to the display of Comet Kohoutek (C/1973 E1) in 1973, which had been widely predicted to be the "comet of the century" but in the end fell well short and was very disappointing. As a result scientists were wary of making predictions, in particular those of a spectacular nature.

At peak the comet displayed a sensational curved fanned tail tens of degrees in length. Comet McNaught (C/2006 P1) in 2007 was similar in appearance. 

With a near parabolic orbit, the orbital period is very difficult to accurately calculate. Estimates range from 250,000 years to 6 million years.