C/1893 N1 (Rordame–Quénisset)

For the other comet discovered by Ferdinand Quénisset, see C/1911 S2 (Quénisset).

Comet Rordame–Quénisset, also known as C/1893 N1 by its modern nomenclature, is a hyperbolic comet that was visible in the naked eye in 1893. It was discovered independently by Alfred Rordame and Ferdinand Quénisset, though several astronomers reportedly saw the comet days before their respective discoveries.

C/1893 N1 (Rordame-Quénisset)

Comet Rordame–Quénisset photographed by W. J. Hussey from the Lick Observatory on 13 July 1893
Discovery[1][2]
Discovered by	Alfred Rordame Ferdinand Quénisset
Discovery site	Salt Lake City, USA Juvisy-sur-Orge, France
Discovery date	8–9 July 1893
Designations
Alternative designations	1893b[3] 1893 II
Orbital characteristics[4]
Epoch	19 July 1893 (JD 2412663.5)
Observation arc	15 days
Earliest precovery date	20 June 1893
Number of observations	15
Perihelion	0.6744 AU
Eccentricity	1.001703
Inclination	159.975°
Longitude of ascending node	338.861°
Argument of periapsis	47.149°
Last perihelion	7 July 1893
TJupiter	–0.953
Earth MOID	0.1169 AU
Jupiter MOID	0.2267 AU
Physical characteristics
Apparent magnitude	3.0 (1893 apparition)

Discovery and observations

It is unknown who were the actual discoverers of C/1893 H1, however both Alfred Rordame and Ferdinand Quénisset were the first people to report the comet's discovery on 8 and 9 July 1893, respectively.^[1] The comet was a 3rd-magnitude object in the constellation Lynx at the time of discovery.^[2]

It was only later that it turned out that several other astronomers had already spotted the comet beforehand. Amateur astronomers, J. Miller and C. Johnson, claimed they have both observed the comet from Alta, Iowa about 2–3 hours before Rordame made his report to Lewis A. Swift.^[2] Across the Atlantic, Mario Roso de Luna reportedly saw the comet from Logrosan, Spain on July 4,^[5] however he didn't recognized it as a new comet until August 1893 when orbital calculations of de Luna's comet had concluded it was that same object as Rordame–Quénisset.^[1] The earliest known prediscovery observations of the comet was made on 20 June 1893, where William E. Sperra observed the comet a dozen times from Randolph, Ohio but he mistook it for 15P/Finlay in his observation reports.^[6]

Orbital calculations in October 1893 determined that the comet had already passed perihelion a day before the official discovery reports were made.^[7] It was last observed as a 6th-magnitude object on 3 August 1893, as further observations were made difficult due to increasingly unfavourable low positions in the night sky and a bright full Moon at the time.^[8]

See also

• C/1893 U1 (Brooks)