The Lunar X (also known as the Werner X) is a clair-obscur effect in which light and shadow creates the appearance of a letter 'X' on the rim of the Blanchinus, La Caille and Purbach craters. [1]
The X is visible only for a few hours before the first quarter, [2] [3] slightly below the lunar terminator. Near to the X, the Lunar V is also visible, formed by Ukert crater and several other small craters. [2]
The Eagle Nebula is a young open cluster of stars in the constellation Serpens, discovered by Jean-Philippe de Cheseaux in 1745–46. Both the "Eagle" and the "Star Queen" refer to visual impressions of the dark silhouette near the center of the nebula, an area made famous as the "Pillars of Creation" imaged by the Hubble Space Telescope. The nebula contains several active star-forming gas and dust regions, including the aforementioned Pillars of Creation. The Eagle Nebula lies in the Sagittarius Arm of the Milky Way.
Alphonsus is an ancient impact crater on the Moon that dates from the pre-Nectarian era. It is located on the lunar highlands on the eastern end of Mare Nubium, west of the Imbrian Highlands, and slightly overlaps the crater Ptolemaeus to the north. To the southwest is the smaller Alpetragius. The crater name was approved by the IAU in 1935.
Copernicus is a lunar impact crater located in eastern Oceanus Procellarum. It was named after the astronomer Nicolaus Copernicus. It typifies craters that formed during the Copernican period in that it has a prominent ray system. It may have been created by debris from the breakup of the parent body of asteroid 495 Eulalia 800 million years ago.
Arzachel is a relatively young lunar impact crater located in the highlands in the south-central part of the visible Moon, close to the zero meridian. It lies to the south of the crater Alphonsus, and together with Ptolemaeus further north the three form a prominent line of craters to the east of Mare Nubium. The smaller Alpetragius lies to the northwest, and Thebit is to the southwest along the edge of the mare.
Astronomy Picture of the Day (APOD) is a website provided by NASA and Michigan Technological University (MTU). According to the website, "Each day a different image or photograph of our universe is featured, along with a brief explanation written by a professional astronomer." The photograph does not necessarily correspond to a celestial event on the exact day that it is displayed, and images are sometimes repeated. However, the pictures and descriptions often relate to current events in astronomy and space exploration. The text has several hyperlinks to more pictures and websites for more information. The images are either visible spectrum photographs, images taken at non-visible wavelengths and displayed in false color, video footage, animations, artist's conceptions, or micrographs that relate to space or cosmology. Past images are stored in the APOD Archive, with the first image appearing on June 16, 1995. This initiative has received support from NASA, the National Science Foundation, and MTU. The images are sometimes authored by people or organizations outside NASA, and therefore APOD images are often copyrighted, unlike many other NASA image galleries.
Eratosthenes crater is a relatively deep lunar impact crater that lies on the boundary between the Mare Imbrium and Sinus Aestuum mare regions. It forms the western terminus of the Montes Apenninus mountain range. It is named after ancient Greek astronomer Eratosthenes of Cyrene, who estimated the circumference of the Earth, and the distance from the Earth to the Sun.
Ptolemaeus is an ancient lunar impact crater close to the center of the near side, named for Claudius Ptolemy, the Greco-Roman writer, mathematician, astronomer, geographer and astrologer. It measures approximately 154 kilometers in diameter.
Hipparchus is the degraded remnant of a lunar impact crater. It was named after the Greek astronomer, geographer and mathematician Hipparchus. It is located to the southeast of Sinus Medii, near the center of the visible Moon. To the south is the prominent crater Albategnius, and to the southwest lies Ptolemaeus, a feature of comparable dimensions to Hipparchus. Horrocks lies entirely within the northeast rim of the crater. Halley is attached to the south rim, and Hind lies to the southeast. To the north-northeast is the bowl-shaped Pickering, and the flooded Saunder is located off the northeast rim. High-resolution images of Hipparchus were obtained by Lunar Orbiter 5 in 1967.
Purbach is a large lunar impact crater in the rugged southern highlands of the Moon. The distorted crater Regiomontanus is attached to the southern rim. To the northwest is Thebit and just to the northeast lies La Caille.
La Caille is a lunar impact crater located in the rugged south-central highlands of the Moon. It was named after the French astronomer Nicolas-Louis de Lacaille. It is located to the northeast of the crater Purbach. Nearly attached to the southeast rim are the remains of Blanchinus, and the two are separated by a rugged stretch of terrain. To the northeast is Delaunay, a formation split in half by a ridge.
Blanchinus is a lunar impact crater in the rugged south-central highlands of the Moon. It is named after Italian astronomer Giovanni Bianchini whose Latinized name is Blanchinus. Adjacent to its south is the crater Werner, and La Caille is attached to the northwest rim. To its west is the prominent formation Purbach.
Ukert is a lunar impact crater that lies on a strip of rugged ground between Mare Vaporum to the north and Sinus Medii in the south. It was named after German historian Friedrich August Ukert. It is located to the north-northwest of the crater Triesnecker and northeast of the crater pair of Pallas and Murchison.
Sinus Iridum is a plain of basaltic lava that forms a northwestern extension to the Mare Imbrium on Earth's moon. It is surrounded from the northeast to the southwest by the Montes Jura range. The protruding part of the range at the southwest end is named Promontorium Heraclides, while that at the northeast end is called Promontorium Laplace. This bay and the surrounding mountains is considered one of the most beautiful features on the Moon, and is a favorite among lunar observers.
The Veil Nebula is a cloud of heated and ionized gas and dust in the constellation Cygnus.
A bipolar nebula is a type of nebula characterized by two lobes either side of a central star. About 10-20% of planetary nebulae are bipolar.
NGC 7635, also known as the Bubble Nebula, Sharpless 162, or Caldwell 11, is an H II region emission nebula in the constellation Cassiopeia. It lies close to the open cluster Messier 52. The "bubble" is created by the stellar wind from a massive hot, 8.7 magnitude young central star, SAO 20575 (BD+60°2522). The nebula is near a giant molecular cloud which contains the expansion of the bubble nebula while itself being excited by the hot central star, causing it to glow. It was discovered in November 1787 by William Herschel. The star BD+60°2522 is thought to have a mass of about 44 M☉.
Earthlight is the diffuse reflection of sunlight reflected from Earth's surface and clouds. Earthshine, also known as the Moon's ashen glow, is the dim illumination of the otherwise unilluminated portion of the Moon by this indirect sunlight. Earthlight on the Moon during the waxing crescent is called "the old Moon in the new Moon's arms", while that during the waning crescent is called "the new Moon in the old Moon's arms".
Proctor is a large crater in the Noachis quadrangle of Mars. It measures 168.2 kilometres in diameter and was named after Richard A. Proctor, a British astronomer (1837–1888).
Solar eclipses on the Moon are caused when the planet Earth passes in front of the Sun and blocks its light. Viewers on Earth experience a lunar eclipse during a solar eclipse on the Moon.
Robert J. Nemiroff is an Astrophysicist and Professor of Physics at Michigan Technological University. He received his Ph.D. from the University of Pennsylvania in Astronomy and Astrophysics in 1987 and his B.S. from Lehigh University in Engineering Physics in 1982. He is an active researcher with interests that include gamma-ray bursts, gravitational lensing, and cosmology, and is the cofounder and coeditor of Astronomy Picture of the Day (APOD), the home page of which receives over a million hits a day, approximately 20% of nasa.gov traffic. He is married and has one daughter.
 | This article related to the Moon is a stub. You can help Wikipedia by expanding it. |