Comet Westformally designated C/1975 V11976 VI, and 1975n, was a comet described as one of the brightest objects to pass through the inner solar system in 1976. It is often described as a "great comet.

It was discovered photographically by Richard M. West, of the European Southern Observatory, on August 10, 1975. The comet came to perihelion (closest approach to the Sun) on February 25, 1976. During perihelion the comet had a minimum solar elongation of 6.4 and as a result of forward scattering reached a peak apparent magnitude of -3.0. From February 25 through the 27th, observers reported that the comet was bright enough to study during full daylight

Despite its brightness, Comet West went largely unreported in the popular media. This was partly due to the relatively disappointing display of Comet Kohoutek in 1973, which had been widely predicted to become extremely prominent: scientists were wary of making predictions that might raise public expectations

With a nearly parabolic trajectory, estimates for the orbital period of this comet have varied from 254,000 to 558,000 years, and even as high as 6.5 million years. Computing the best-fit orbit for this long-period comet is made more difficult since it underwent a splitting event which may have caused a non-gravitational perturbation of the orbit. The 2008 SAO Catalog of Cometary Orbits shows 195 observations for C/1975 V1 and 135 for C/1975 V1-A, for a combined total of 330 (218 observations were used in the fit). Comet C/1999 F1 has a similar period. Aphelion is estimated at 70,000 AU, but orbital periods of millions of years are very unstable as they are subject to perturbations by passing stars and the galactic tide.

Before the perihelion passage, and using 28 positions obtained between 1975 August 10 and 1976 January 27, Comet West was estimated to have an orbital period of about 254,000 years. As the comet passed within 30 million km of the Sun, the nucleus was observed to split into four fragments\

The first report of the split came around 7 March 1976 12:30UT, when reports were received that the comet had broken into two pieces. Astronomer Steven O'Meara, using the 9-inch Harvard Refractor, reported that two additional fragments had formed on the morning of 18 March

The fragmentation of the nucleus was, at the time, one of very few comet breakups observed, one of the most notable previous examples being the Great Comet of 1882, a member of the Kreutz Sungrazing 'family' of comets. More recently, comets Schwassmann-Wachmann-3 (73/P), C/1999 S4 LINEAR, and 57/P du Toit-Neujmin-Delporte, have been observed to disintegrate during their passage close to the Sun.

In the nomenclature of the time, it was known as Comet 1976 VI or Comet 1975n, but the modern nomenclature is C/1975 V1. (Note that "1976 VI" uses the Roman numeral VI = 6, while "C/1975 V1" is the letter V and the number 1)




Comet West was a truly spectacular comet, sometimes considered to qualify for the status of "great comet". It was discovered photographically by Richard M. West, of the European Southern Observatory, on August 10, 1975, and reached peak brightness in March 1976, attaining a brightness of -3rd magnitude at perihelion. During peak brightness, observers reported that it was bright enough to study during full daylight.

Comet West was what 1973's Comet Kohoutek should have been. Kohoutek was overhyped and underperforming, and West was the exact opposite. If anything, it was underhyped, because no one wanted to get burned again making ambitious predictions. As a result, Comet West was largely unheralded outside the astronomical community.

The comet has an estimated orbital period of ~559,000 years.  During the comet's run into the inner solar system for the first time in 600,000 years, the nucleus of Comet West was observed to split into four fragments as it passed within 30 million km. of the sun. The first report of the split came around 7 March 1976 12:30UT, when reports were received that the comet had broken into two pieces. These two fragments remained the only pieces until Steven O'Meara, using the 9-inch Harvard Refractor, reported that two additional fragments had formed on the morning of 18 March.

The breakup was one of very few comet breakups observed from historical times by the 1970s. Recently, comets Shoemaker-Levy 9, Schwassmann-Wachmann-3 (73/P), C/1999 S4 LINEAR, and 57/P du Toit-Neujmin-Delporte, have been observed to disintegrate. When observed, many were stunned, but none more so than the discoverer, Richard Martin West. The comet broke into pieces when some distance from the sun. It exploded into four pieces, and those were scattered. Later, two pieces were spotted, and studied intently by astronomers.

While I did not observe Comet West myself, it was the comet that  got me started on my journey of discovery. I joined the Black River Astronomical Society in the fall of  1976 and the guys were abuzz with excitement over the still recent apparition of Comet West. They showed me pictures and pencil drawings and one of the members, Carl Peck, an avid comet chaser, gave a talk on it.

I remembered being amazed at his knowledge of comets and something he said hit home with me. Basically, he said that comets were transient creatures that roamed the very depths of space, some since the beginning of time. Comets, he went on,  held the key to all life in the universe and actually contained the seeds of life and could be responsible for bringing all the water on Earth to us...

Every comet, he said, was a once in a lifetime event in that every comet is totally unique unto itself. Even periodic comets, he explained, returning again and again, exhibit totally different behaviour over each individual apparition.

That talk ignited a fire in my young brain, and I determined that night, so many years ago, to observe every comet within my powers.