Category Archives: Constellations

A brief description and some very basic information about constellations visible at 40-degrees north latitude.

Corona Australis (The southern crown)

Constellation Corona AustralisCorona Australis is a southern constellation that was cataloged by 2nd century astronomer Ptolemy, and remains among the 88 modern constellations. This horseshoe-shaped constellation lies about as far south as, and adjacent to the crook of Scorpius’ tail, and just beneath the teapot asterism of Sagittarius. Because of its far southern location in the celestial sphere, it barely rises above the southern horizon before setting again. Corona Australis reaches its highest nightfall ascension in September.

This constellation provides the foreground stars for a portion of the Milky Way pointing in a direction near the center of our galaxy. The most notable object in this region is the Corona Australis Molecular Cloud, a large and dark molecular cloud with many embedded reflection nebulae. There are many other telescopically interesting objects in this constellation to include star-forming regions with proto-stars, galaxies, and variable stars.
http://en.wikipedia.org/wiki/Corona_Australis

IAU Corona Australis chart, IAU and Sky & Telescope magazine (Roger Sinnott and Rick Fienberg), June 5, 2011.
IAU Corona Australis chart, IAU and Sky & Telescope magazine (Roger Sinnott and Rick Fienberg), June 5, 2011.

© James R. Johnson, 2014.
jim@jrjohnson.net

Centaurus (The centaur)

Constellation CentaurusCentaurus is a large, bright southern constellation that is among the 48 constellations cataloged by 2nd century astronomer Ptolemy. Because it is located so far south on the celestial sphere, it rises only partially above the horizon at a 40-degree north location. It reaches its highest nightfall ascension in May. This constellation has the distinction of hosting our nearest stellar neighbor, the Alpha Centauri system. Located just over four light years away, this system consists of three components: Alpha Centauri A, B and C. Alpha Centauri C is also known as Proxima, which is actually the nearest of the three component stars, and the only one that cannot be seen with the unaided eye.
http://en.wikipedia.org/wiki/Centaurus

IAU Centaurus chart, IAU and Sky & Telescope magazine (Rober Sinnott and Rick Fienberg), June 4, 2011.
IAU Centaurus chart, IAU and Sky & Telescope magazine (Rober Sinnott and Rick Fienberg), June 4, 2011.

© James R. Johnson, 2014.
jim@jrjohnson.net

Ara (The altar)

Constellatiion AraAra, the altar, is a southern constellation that is so far south as to never rise above the horizon for viewers at 40-degrees north latitude. It is included in this collection to complete the descriptions of the 48 constellations cataloged by 2nd century astronomer Ptolemy. For those traveling south, to say Florida or farther, look for Ara to reach its highest nightfall ascension in July. It is located just beneath the crook of Scorpius’ tail.
http://en.wikipedia.org/wiki/Ara_(constellation)

IAU Ara chart, IAU and Sky & Telescope magazine (Roger Sonnott & Rick Fienberg), June 4, 2011.
IAU Ara chart, IAU and Sky & Telescope magazine (Roger Sinnott & Rick Fienberg), June 4, 2011.

© James R. Johnson, 2014.
jim@jrjohnson.net

Corvus (The raven)

CorvusCorvus is a southern constellation that was cataloged by 2nd century astronomer Ptolemy that remains among the 88 modern constellations. It’s four brightest stars form a distinct quadrilateral asterism that lies beneath Virgo’s back, adjacent to Crater, and above Hydra near its tail. This constellation reaches its highest nightfall ascension in May. Because of its deep southern declination, it sets shortly after setting, and it never rises very far above the horizon.

NGC40384039_largeThere are no Messier objects in Corvus, but there is a very interesting pair of NGC galaxies, the Antennae peculiar galaxy (NGC 4038 and 4039).  These two objects are undergoing a galactic collision which is stretching them out into unusual antenna-like shapes. “Peculiar” is a term given to any galaxy that does not have the usual spiral or elliptical shape.
http://en.wikipedia.org/wiki/Corvus_(constellation)

IAU Corvus chart, IAU and Sky & Telescope magazine (Roger Sinnertt and Rick Fienberg), June 5, 2011.
IAU Corvus chart, IAU and Sky & Telescope magazine (Roger Sinnott and Rick Fienberg), June 5, 2011.

© James R. Johnson, 2014.
jim@jrjohnson.net

Leo Minor (The lesser lion)

Leo, Leo MinorLeo Minor is a northern constellation that walks the sky below Ursa Major’s hind legs and above Leo’s mane. Ptolemy, the 2nd century astronomer that cataloged many of today’s modern constellations, noted that the region of Leo Minor was undefined, and it remained that way until Johannes Hevelius first depicted it in 1687. Lying just outside the circle that defines circumpolar objects, this constellation can be seen most of the night year ’round, and it reaches its highest nightfall ascension in April. There are no Messier objects in Leo Minor, but there are several NGC objects available to the determined amateur astronomer’s telescope.
http://en.wikipedia.org/wiki/Leo_Minor

IAU Leo Minor chart, IAU and Sky & Telescope magazine (Roger Sinnott and Rick Fienberg), June 5, 2011.
IAU Leo Minor chart, IAU and Sky & Telescope magazine (Roger Sinnott and Rick Fienberg), June 5, 2011.

© James R. Johnson, 2014.
jim@jrjohnson.net

Lupus (The wolf)

Constellation LupusLupus, the wolf, is one of the 48 constellations cataloged by 2nd century astronomer Ptolemy that remain among the 88 modern constellations defined by the International Astronomical Union. It is a southern constellation that is so far south that it barely peeks above the horizon in June and July for viewers at 40-degree north locations. It is situated beneath the scales of Libra, and to the right of Scorpius. There are no Messier objects in Lupus, and the several NGC objects located there are difficult for northern observers because of the constellation’s low placement on the horizon.
http://en.wikipedia.org/wiki/Lupus_(constellation)

IAU Lupus chart, IAU and Sky & Telescope magazine (Roger Sinnott and Rick Fienberg), June 5, 2011..
IAU Lupus chart, IAU and Sky & Telescope magazine (Roger Sinnott and Rick Fienberg), June 5, 2011..

© James R. Johnson, 2014.
jim@jrjohnson.net

Sextans (The astronomical sextant)

Leo, Hydra, SextansSextans is Latin for astronomical sextant, and was so-named by Johannes Hevelius who frequently used this instrument for his observations. Sextans is very dim as its brightest star barely exceeds 5th magnitude – close to the limit that can be seen with the unaided eye. Sextans is located on the celestial equator below Leo’s front leg, and Hydra slithers along below it. This constellation reaches its highest nightfall ascendance in April, and it contains little else of interest to the amateur astronomer.
http://en.wikipedia.org/wiki/Sextans

IAU Sextans chart, IAU and Sky & Telescope magazine (Roger Sinnott and Rick Fienberg), June 5, 2011.
IAU Sextans chart, IAU and Sky & Telescope magazine (Roger Sinnott and Rick Fienberg), June 5, 2011.

© James R. Johnson, 2014.
jim@jrjohnson.net

Serpens (The serpent)

Serpens Caput, Corona Borealis Sagittarius, Scutum, SerpensSerpens is unique among modern constellations in that it is separated into two parts. Serpens Caput, the head, begins near Corona Borealis, and descends southward until it connects to Ophiuchus (the serpent bearer). Serpens Cauda, the tail, begins on the other side of Ophiuchus and ascends north and eastward, terminating near Aquila. Serpens is often depicted as passing behind Ophiuchus and emerging from the other side. Since Serpens is a lengthy constellation that extends primarily in an east-west direction, it reaches its highest nightfall ascension beginning in June with the head and ending with the tail in August. The entire constellation is situated for best nightfall viewing in July.

Serpens Cauda extends into the Milky Way, so there are several deep sky objects in that section. Two of these are Messier objects, M5, and M16 (the Eagle Nebula, which includes the Pillars of Creation and its associated star cluster). Hoag’s Object is a face-on example of a very rare class of galaxies known as ring galaxy.
http://en.wikipedia.org/wiki/Serpens

IAU Serpens Caput chart, IAU and Sky & Telescope magazine (Roger Sinnert and Rick Fienbert), March 21, 2012.
IAU Serpens Caput chart, IAU and Sky & Telescope magazine (Roger Sinnott and Rick Fienbert), March 21, 2012.
IAU Serpens Cauda chart, IAU and Sky & Telescope magazine (Roger Sinnertt and Rick Fienberg), March 21, 2012.
IAU Serpens Cauda chart, IAU and Sky & Telescope magazine (Roger Sinnott and Rick Fienberg), March 21, 2012.

© James R. Johnson, 2014.
jim@jrjohnson.net

Scutum (The shield)

Scutum, SagittariusOriginally named Scutum Sobiescianum (Shield of Sobieski) to commemorate the victory of Christian forces led by Polish King John III Sobieski in the Battle of Vienna in 1683, the name was later shortened to Scutum. This is a small, dim constellation located between the tail of Aquila, above the head of Sagittarius, and to the left of Ophiuchus. Scutum reaches its highest nightfall ascension in August. It contains two Messier star clusters, M11 (the Wild Duck Cluster), and M26 (NGC 6694).
http://en.wikipedia.org/wiki/Scutum

609px-Scutum_IAU.svg
IAU Scutum chart, IAU and Sky & Telescope magazine (Roger Sinnott and Rick Fienberg), June 5, 2011.

 

© James R. Johnson, 2014.
jim@jrjohnson.net

Hydra (The water snake)

Hydra, SextansHydra is the largest of the 88 modern constellations, and was one of the 48 constellations cataloged by 2nd century astronomer Ptolemy. Hydra’s head lies at a point about halfway between Procyon in Canis Minor and Regulus in Leo. From there, it snakes (pun intended) south and eastward below Leo and Virgo, sharing two stars with Crater along the way, before ending just below the right scale of Libra. Hydra’s head reaches its highest nightfall ascension in March, but the tail does not reach that point until three months later in June. The best over all view of Hydra is in late April. Hydra is home to three Messier objects: M83 (the Southern Pinwheel Galaxy), M68 (a globular star cluster), and M48 (an open star cluster).
http://en.wikipedia.org/wiki/Hydra_(constellation)

IAU Hydra chart, IAU and Sky & Telescope magazine (Roger Sinnott and Rick Fienberg), June 5, 2011.
IAU Hydra chart, IAU and Sky & Telescope magazine (Roger Sinnott and Rick Fienberg), June 5, 2011.

© James R. Johnson, 2014.
jim@jrjohnson.net