Messier 74 is a large spiral galaxy in the equatorial constellation Pisces. It is about 32 million light-years away from Earth. The galaxy contains two clearly defined spiral arms and is therefore used as an archetypal example of a grand design spiral galaxy. The galaxy's low surface brightness makes it the most difficult Messier object for amateur astronomers to observe. Its relatively large angular size and the galaxy's face-on orientation make it an ideal object for professional astronomers who want to study spiral arm structure and spiral density waves. It is estimated that M74 hosts about 100 billion stars.
NGC 6946, sometimes referred to as the Fireworks Galaxy, is a face-on intermediate spiral galaxy with a small bright nucleus, whose location in the sky straddles the boundary between the northern constellations of Cepheus and Cygnus. Its distance from Earth is about 25.2 million light-years or 7.72 megaparsecs, similar to the distance of M101 in the constellation Ursa Major. Both were once considered to be part of the Local Group, but are now known to be among the dozen bright spiral galaxies near the Milky Way but beyond the confines of the Local Group. NGC 6946 lies within the Virgo Supercluster.
Leuschner Observatory, originally called the Students' Observatory, is an observatory jointly operated by the University of California, Berkeley and San Francisco State University. The observatory was built in 1886 on the Berkeley campus. For many years, it was directed by Armin Otto Leuschner, for whom the observatory was renamed in 1951. In 1965, it was relocated to its present home in Lafayette, California, approximately 10 miles (16 km) east of the Berkeley campus. In 2012, the physics and astronomy department of San Francisco State University became a partner.
SN 1994D was a Type Ia supernova event in the outskirts of galaxy NGC 4526. It was offset by 9.0″ west and 7.8″ south of the galaxy center and positioned near a prominent dust lane. It was caused by the explosion of a white dwarf star composed of carbon and oxygen. This event was discovered on March 7, 1994 by R. R. Treffers and associates using the automated 30-inch telescope at Leuschner Observatory. It reached peak visual brightness two weeks later on March 22. Modelling of the light curve indicates the explosion would have been visible around March 3-4. A possible detection of helium in the spectrum was made by W. P. S. Meikle and associates in 1996. A mass of 0.014 to 0.03 M☉ in helium would be needed to produce this feature.
NGC 2207 and IC 2163 are a pair of colliding spiral galaxies about 80 million light-years away in the constellation Canis Major. Both galaxies were discovered by John Herschel in 1835.
NGC 1309 is a spiral galaxy located approximately 120 million light-years away, appearing in the constellation Eridanus. It is about 75,000 light-years across, and is about 3/4s the width of the Milky Way. Its shape is classified as SA(s)bc, meaning that it has moderately wound spiral arms and no ring. Bright blue areas of star formation can be seen in the spiral arms, while the yellowish central nucleus contains older-population stars. NGC 1309 is one of over 200 members of the Eridanus Group of galaxies.
Alexei Vladimir "Alex" Filippenko is an American astrophysicist and professor of astronomy at the University of California, Berkeley. Filippenko graduated from Dos Pueblos High School in Goleta, California. He received a Bachelor of Arts in physics from the University of California, Santa Barbara in 1979 and a Ph.D. in astronomy from the California Institute of Technology in 1984, where he was a Hertz Foundation Fellow. He was a postdoctoral Miller Fellow at Berkeley from 1984 to 1986 and was appointed to Berkeley's faculty in 1986. In 1996 and 2005, he was a Miller Research Professor, and he is currently a Senior Miller Fellow. His research focuses on supernovae and active galaxies at optical, ultraviolet, and near-infrared wavelengths, as well as on black holes, gamma-ray bursts, and the expansion of the Universe.
The known history of supernova observation goes back to 1006 AD. All earlier proposals for supernova observations are speculations with many alternatives.
SN 2006gy was an extremely energetic supernova, also referred to as a hypernova, that was discovered on September 18, 2006. It was first observed by Robert Quimby and P. Mondol, and then studied by several teams of astronomers using facilities that included the Chandra, Lick, and Keck Observatories. In May 2007, NASA and several of the astronomers announced the first detailed analyses of the supernova, describing it as the "brightest stellar explosion ever recorded". In October 2007, Quimby announced that SN 2005ap had broken SN 2006gy's record as the brightest-ever recorded supernova, and several subsequent discoveries are brighter still. Time magazine listed the discovery of SN 2006gy as third in its Top 10 Scientific Discoveries for 2007.
SN 1999ec was a type Ib supernova that was discovered in the interacting galaxy NGC 2207 on October 2, 1999. It was found on images taken with the Katzman Automatic Imaging Telescope at the Lick Observatory. The progenitor is estimated to have had 38 times the mass of the Sun and was 5.34 million years old at the time of the outburst.
SN 2003H was a supernova that appeared halfway between the colliding NGC 2207 and IC 2163 galaxies. It was discovered on January 8, 2003, by the Lick Observatory and Tenagra Supernova Searches (LOTOSS).
NGC 6118 is a grand design spiral galaxy located 83 million light-years away in the constellation Serpens. It was discovered on 14 April 1785 by German-British astronomer William Herschel.
Puckett Observatory is a private astronomical observatory located in the state of Georgia. It is owned and operated by Tim Puckett. Its primary observation goals are the study of comets and the discovery of supernovae. To facilitate the latter goal it sponsors the Puckett Observatory World Supernova Search whose astronomers have discovered 369 supernovae.
SN 2014J was a type-Ia supernova in Messier 82 discovered in mid-January 2014. It was the closest type-Ia supernova discovered for 42 years, and no subsequent supernova has been closer as of 2023. The supernova was discovered by chance during an undergraduate teaching session at the University of London Observatory. It peaked on 31 January 2014, reaching an apparent magnitude of 10.5. SN 2014J was the subject of an intense observing campaign by professional astronomers and was bright enough to be seen by amateur astronomers.
A type Iax supernova is a rare subtype of type Ia supernova, which leaves behind a remnant star, known as zombie star, rather than completely dispersing the white dwarf. Type Iax supernovae are similar to type Ia, but have a lower ejection velocity and lower luminosity. Type Iax supernovae may occur at a rate between 5 and 30 percent of the Ia supernova rate. As of October 2014, thirty supernovae had been identified in this category.
NGC 3198, also known as Herschel 146 is a barred spiral galaxy in the constellation Ursa Major. It was discovered by William Herschel on 15 January 1788. NGC 3198 is located in the Leo Spur, which is part of the Virgo Supercluster, and is approximately 47 million light years away.
NGC 4490, also known as the Cocoon Galaxy, is a barred spiral galaxy in the constellation Canes Venatici. William Herschel discovered it in 1788. It is known to be of the closest interacting/merging galactic system. The galaxy lies at a distance of 25 million light years from Earth making it located in the local universe. It interacts with its smaller companion NGC 4485 and as a result is a starburst galaxy. NGC 4490 and NGC 4485 are collectively known in the Atlas of Peculiar Galaxies as Arp 269. The two galaxies has already made their closest approach and are rushing away from each other. It's been discovered that NGC 4490 has a double nucleus.
SN 2013ej is a Type II-P supernova in the nearby spiral galaxy Messier 74. It was discovered by the Lick Observatory Supernova Search on July 25, 2013, with the 0.76 m Katzman Automatic Imaging Telescope, with pre-discovery images having been taken the day before.
NGC 3746 is a large barred spiral galaxy with a ring structure located in the Leo constellation. It is located 449 million light-years from the Solar System and has an approximate diameter of 165,000 light-years. NGC 3746 was discovered by Ralph Copeland on 9 February 1874 with subsequent observations made by Hermann Kobold, Lawrence Parsons and John Louis Emil Dreyer.
IC 5145 is a type Sab spiral galaxy located in the constellation Pegasus. It is located 356 million light-years from the Solar System and was discovered by Edward Emerson Barnard, although the year he discovered it is unknown.
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