Ophiuchus is a large constellation straddling the celestial equator. Its name comes from the Ancient Greek ὀφιοῦχος (ophioûkhos), meaning "serpent-bearer", and it is commonly represented as a man grasping a snake. The serpent is represented by the constellation Serpens. Ophiuchus was one of the 48 constellations listed by the 2nd-century astronomer Ptolemy, and it remains one of the 88 modern constellations. An old alternative name for the constellation was Serpentarius.
Telescopium is a minor constellation in the southern celestial hemisphere, one of twelve named in the 18th century by French astronomer Nicolas-Louis de Lacaille and one of several depicting scientific instruments. Its name is a Latinized form of the Greek word for telescope. Telescopium was later much reduced in size by Francis Baily and Benjamin Gould.
Vela is a constellation in the southern sky, which contains the Vela Supercluster. Its name is Latin for the sails of a ship, and it was originally part of a larger constellation, the ship Argo Navis, which was later divided into three parts, the others being Carina and Puppis. With an apparent magnitude of 1.8, its brightest star is the hot blue multiple star Gamma Velorum, one component of which is the closest and brightest Wolf-Rayet star in the sky. Delta and Kappa Velorum, together with Epsilon and Iota Carinae, form the asterism known as the False Cross. 1.95-magnitude Delta is actually a triple or quintuple star system.
Eta Canis Majoris, also named Aludra, is a star in the constellation of Canis Major. Since 1943, the spectrum of this star has served as one of the stable anchor points by which other stars are classified.
The American Association of Variable Star Observers (AAVSO) is an international nonprofit organization. Founded in 1911, the organization focuses on coordinating, analyzing, publishing, and archiving variable star observations made largely by amateur astronomers. The AAVSO creates records that establish light curves depicting the variation in brightness of a star over time. The AAVSO makes these records available to professional astronomers, researchers, and educators.
Zeta Ophiuchi is a single star located in the constellation of Ophiuchus. It has an apparent visual magnitude of 2.6, making it the third-brightest star in the constellation. Parallax measurements give an estimated distance of roughly 366 light-years from the Earth. It is surrounded by the Sh2-27 "Cobold" nebula, the star's bow shock as it ploughs through dense dust clouds near the Rho Ophiuchi cloud complex.
V382 Velorum, also known as Nova Velorum 1999, was a bright nova which occurred in 1999 in the southern constellation Vela. V382 Velorum reached a brightness of 2.6 magnitude, making it easily visible to the naked eye. It was discovered by Peter Williams of Heathcote, New South Wales, Australia at 09:30 UT on 22 May 1999. Later that same day it was discovered independently at 10:49 UT by Alan C. Gilmore at Mount John University Observatory in New Zealand.
RS Ophiuchi is a recurrent nova system approximately 5,000 light-years away in the constellation Ophiuchus. In its quiet phase it has an apparent magnitude of about 12.5. It has been observed to erupt in 1898, 1933, 1958, 1967, 1985, 2006 and 2021 and reached about magnitude 5 on average. A further two eruptions, in 1907 and 1945, have been inferred from archival data. The recurrent nova is produced by a white dwarf star and a red giant in a binary system. About every 15 years, enough material from the red giant builds up on the surface of the white dwarf to produce a thermonuclear explosion. The white dwarf orbits close to the red giant, with an accretion disc concentrating the overflowing atmosphere of the red giant onto the white dwarf.
Robert Owen Evans, OAM was an Australian minister of the Uniting Church in Hazelbrook, New South Wales, and an amateur astronomer who holds the record for visual discoveries of supernovae (42).
A dwarf nova, or U Geminorum variable, is one of several types of cataclysmic variable star, consisting of a close binary star system in which one of the components is a white dwarf that accretes matter from its companion. Dwarf novae are dimmer and repeat more frequently than "classical" novae.
The known history of supernova observation goes back to 1006 AD. All earlier proposals for supernova observations are speculations with many alternatives.
IK Pegasi is a binary star system in the constellation Pegasus. It is just luminous enough to be seen with the unaided eye, at a distance of about 154 light years from the Solar System.
Albert Francis Arthur Lofley Jones was a New Zealand amateur astronomer, and a prolific variable star and comet observer, a member of the Variable Star Section and the Comet Section of the Royal Astronomical Society of New Zealand.
Michiel Daniel Overbeek, also known as Danie Overbeek, was a South African amateur astronomer and one of the most prolific variable star observers.
Gregg D. Thompson of Brisbane, Australia is an amateur astronomer.
Sutherland Astronomical Society Incorporated (SASI) is an amateur astronomical society based in the Sutherland Shire, in the southern suburbs of Sydney, Australia. It operates the Green Point Observatory, it is one of the two founding organizations of the National Australian Convention of Amateur Astronomers, and its members have discovered two comets and two novae.
The Astronomical Society of New South Wales (ASNSW) is an amateur astronomy club in the state of New South Wales, Australia, founded in 1954.
V841 Ophiuchi was a bright nova discovered by John Russell Hind on 27 April 1848. It was the first object of its type discovered since 1670. At the time of its discovery, it had an apparent magnitude of 5.6, but may have reached magnitude 2 at its peak, making it easily visible to the naked eye. Near peak brightness it was described as "bright red" or "scarlet", probably due to Hα line emission. Its brightness is currently varying slowly around magnitude 13.5. The area of the sky surrounding this nova had been examined frequently by astronomers prior to the nova's discovery, because it was near the reported location of "52 Serpentis", a star John Flamsteed had included in his catalogue with erroneous coordinates.
