Tag Archives: April

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

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

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

Crater (The cup)

CraterCrater is Latin for cup, and this constellation represents the cup of Apollo in Greek mythology. This is one of the 48 constellations identified by the 2nd century astronomer Ptolemy. It is located below Leo’s feet, and behind Virgo’s back in the southern sky, sharing two stars with the constellation Hydra. This constellation reaches its highest nightfall ascension in April. Aside from a handful of NGC objects that are a challenge for amateur astronomers, there is not much to see in this constellation.
http://en.wikipedia.org/wiki/Crater_(constellation)

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

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

Leo (The lion)

Constellation LeoLeo, the lion, is a distinctive zodiacal constellation that was cataloged by 2nd century astronomer Ptolemy. It is located on the ecliptic between Cancer and Virgo, and can be found below the bowl of the Big Dipper with both constellations arriving at their highest nightfall ascension in April.  Leo closely resembles a crouching lion with its rather distinct backward question mark, or sickle asterism. This constellation features the bright star Regulus (Alpha Leonis) at the back of the lion’s head.

The most famous deep sky object in Leo is The Leo Triplet is a close grouping of the galaxies M65, M66 (displayed) and NGC3628 that can be seen together in a single telescopic field of view. For those observing with telescopes, there are several other galaxies cataloged by Charles Messier are located in Leo, to include M65, M66, M95, M96 and M105. Leo is also home to the famous Leonids meteor shower that occurs during November, peaking at about 10 meteors per hour on November 14th and 15th.
http://en.wikipedia.org/wiki/Leo_(constellation)

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

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

Ursa Major (The great bear)

Ursa MajorUrsa Major is a circumpolar constellation that was cataloged by 2nd century astronomer Ptolemy. The Big Dipper asterism is perhaps the most easily identifiable aspect of this constellation. As a circumpolar constellation at 40 degrees north latitude, it can be seen at any time on any clear night from a location with an unobstructed view of the northern horizon. In April, however, Ursa Major reaches its highest ascension at nightfall.

All seven stars comprising the Big Dipper were named by the ancients. The Big Dipper’s handle is the bear’s tail and the bowl is the bear’s hindquarter. Upon closer examination and in a darker sky, all of the constellations stars add to the dipper to form a distinct and complete bear. The two Big Dipper bowl stars opposite the handle are the pointer stars that guide the eye to Polaris, or the north star. Following the arc of the tail away from the bowl, a method sometimes referred to as “arc to Arcturus,” leads the observer to the star Arcturus in the constellation Bootes.  Starting at the end of the tail and moving around through the bottom of the dipper’s bowl, the are: Alkaid (Eta Ursae Majoris), Mizar (Zeta Ursae Majoris) and its naked eye binary companion star Alcor,  Alioth (Epsilon Ursae Majoris), Megrez (Delta Ursae Majoris), Phecda (Gamma Ursae Majoris), Merak (Beta Ursae Majoris), and Dubhe (Alpha Ursae Majoris) . Impress your friends by committing these stars’ names to memory and pointing them out on a late Spring evening when the dipper is high in the northern sky.

Ursa Major contains several Messier objects. A famous pair is M81, a nearly face-on spiral galaxy, and M82, a nearly edge-on galaxy, that gravitationally  interact with one another and can be see within a single field of view of a modest telescope. M101, 108 and 109 are three other Messier galaxies, and M97, a planetary nebula are also found in Ursa Major. One rather odd Messier object is M40, which is the only double star in the Messier catalog.
http://en.wikipedia.org/wiki/Ursa_Major_(constellation)

IAU Ursa Major chart, IAU and Sky & Telescope magazine (Roger Sinnott and Fick Fienberg), June 5, 2011.
IAU Ursa Major chart, IAU and Sky & Telescope magazine (Roger Sinnott and Fick Fienberg), June 5, 2011.

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