Comet Bennett, formally known as C/1969 Y1 (old style 1970 II and 1969i), was one of the two bright comets observed in the 1970s, along with

Comet West Comet West, formally designated C/1975 V1, 1976 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." History It was discovered photograp ...

. The name is also borne by an altogether different comet, C/1974 V2. Discovered by

John Caister Bennett John Caister "Jack" Bennett (born 6 April 1914 in Estcourt, Natal, died 30 May 1990 in Pretoria), was a South African civil servant and amateur astronomer. His mother was British and his father was from Tasmania. He attended school in Ficksburg ...

on December 28, 1969 while still almost two AUs from the

Sun The Sun is the star at the center of the Solar System. It is a nearly perfect ball of hot plasma, heated to incandescence by nuclear fusion reactions in its core. The Sun radiates this energy mainly as light, ultraviolet, and infrared rad ...

, it reached

perihelion An apsis (; ) is the farthest or nearest point in the orbit of a planetary body about its primary body. For example, the apsides of the Earth are called the aphelion and perihelion. General description There are two apsides in any e ...

on March 20, passing closest to Earth on March 26, 1970 as it receded, peaking at magnitude 0.C&MS: C/1969 Y1 (Bennett)
/ref> It was last observed on February 27, 1971.

Observational history

The comet was discovered by

on 28 December 1969 from

Pretoria Pretoria () is South Africa's administrative capital, serving as the seat of the executive branch of government, and as the host to all foreign embassies to South Africa. Pretoria straddles the Apies River and extends eastward into the foot ...

, South Africa, during his comet seeking routine. The comet was located in the costellation

Tucana Tucana (The Toucan) is a constellation of stars in the southern sky, named after the toucan, a South American bird. It is one of twelve constellations conceived in the late sixteenth century by Petrus Plancius from the observations of Pieter D ...

, in 65° south declination, and had an estimated magnitude of 8.5. At that time the comet was about 1.7 AU both from the Sun and the Earth. The orbit was computed by M. P. Candy of the

Perth Observatory The Perth Observatory is the name of two astronomical observatories located in Western Australia (WA). In 1896, the original observatory was founded in West Perth on Mount Eliza overlooking the city of Perth (obs. code 319). Due to the city ...

and it became apparent that the comet could became a bright object by the end of March, during its perihelion at a distance of 0.54 AU, as it moved northwards. The comet became visible to the naked eye in February, and the first week of that month it had a magnitude of 5 and its tail measured about one degree in length. By the end of February the comet had brightened to a magnitude of 3.5 while its tail was about two degrees long. The comet continued to brighten during March, as it approached both the Sun and Earth. By the middle of the month it was a first magnitude with a prominent curved tail about 10 degrees long. The comet reached perihelion on 20 March and crossed the equator on 25 March, becoming better visible in the morning sky of the north hemisphere, staying at an elongation greater than 32 degrees. On 26 March was the perigee of the comet, when it approached Earth at a distance of 0.69 AU. The comet was then at the square of the

Pegasus Pegasus ( grc-gre, Πήγασος, Pḗgasos; la, Pegasus, Pegasos) is one of the best known creatures in Greek mythology. He is a winged divine stallion usually depicted as pure white in color. He was sired by Poseidon, in his role as hor ...

and continued moving northwards until it reached its maximum north declination of 83° in August, when the comet was in the constellation of

Camelopardalis Camelopardalis is a large but faint constellation of the northern sky representing a giraffe. The constellation was introduced in 1612 or 1613 by Petrus Plancius. Some older astronomy books give Camelopardalus or Camelopardus as alternative fo ...

. The comet at the start of April had a magnitude of 1, but as it receded both from the Sun and Earth, it had dimmed to a magnitude of 3-4 by the end of April, when its circumpolar, located in Cassiopeia. The comet had in April two tails, with the longest being 20-25 degrees long. Although by the start of May the comet head had faded to magnitude 5, its tail was still 10-15 degrees long, but by the end of the month it was only 2.5 degrees long. It was last seen by

naked eye Naked eye, also called bare eye or unaided eye, is the practice of engaging in visual perception unaided by a magnifying, light-collecting optical instrument, such as a telescope or microscope, or eye protection. Vision corrected to normal ...

around mid May. The comet was observed to fade during summer, autumn and winter. By the start of July it was around magnitude 10 and by the September it was magnitude 12. In January of 1971 it was photographed as a 18.9 magnitude object. It was last photographed by Elizabeth Roemer on 27 February 1971, when the comet was 4.9 AU from the Sun and 5.3 AU from Earth.

Apollo 13 attempted photograph

Comet Bennett was intended to be photographed by the crew of

Apollo 13 Apollo 13 (April 1117, 1970) was the seventh crewed mission in the Apollo space program and the third meant to land on the Moon. The craft was launched from Kennedy Space Center on April 11, 1970, but the lunar landing was aborted af ...

during their journey to the

Moon The Moon is Earth's only natural satellite. It is the fifth largest satellite in the Solar System and the largest and most massive relative to its parent planet, with a diameter about one-quarter that of Earth (comparable to the width ...

. Their first attempt on April 13, 1970 was unsuccessful. On April 14, 1970, after completing the maneuver to orient the spacecraft for a second attempt, ''Odyssey''s service module ruptured, forcing the cancellation of the mission's scientific objectives and touchdown on the lunar surface.

References

External links

Cometography.com

Orbital simulation
from JPL (Java)
Ephemeris
{{DEFAULTSORT:Bennett, 1969 Y1 Long-period comets 1969 in science 1970 in science Discoveries by amateur astronomers