Spring Constellations of the Northern Hemisphere

Spring Constellations of the Northern Hemisphere

The advent of spring in the Northern Hemisphere is slowly ushering in improved seeing conditions, and along with it, a few seasonal constellations that had been out of view for some time. Apart from Ursa Major that is circumpolar, constellations that are now visible include Leo, Boötes, Hydra, Virgo, Cancer, and Crater, all of which offer at least a few deep-sky objects to view.

Boötes

Boötes derives from an ancient Greek word meaning either ox driver, or ploughman, although it can also mean herdsman, depending on the authority consulted. Three meteor showers have their radiants in Boötes: the January Bootids, the June Bootids that each usually produces only 1-2 meteors per hour even at their peaks, and the Quadrantids, that peak in the first week in January and can produce up to about 40 meteors per hour in a good year.

– Quick Facts

Boötes• Constellation: Boötes
• Coordinates: Between latitudes +90° and -50°.
• Best seen: Best seen at 21:00 (9 p.m.) Local Time during June
• Brightest star: Arcturus, (Alpha Boötis), the third-brightest star in the entire night sky
• Stars with planets: 8 stars with 13 planets between them
• Size: 13th largest constellation
• Area: 907 square degrees
• Neighbouring constellations: Draco, Ursa Major, Canes Venatici, Coma Berenices, Virgo, Serpens Caput, Corona Borealis, and Hercules

– Objects of Interest

Boötes does not contain any Messier objects, and very few deep sky objects that hold any interest for the average amateur astronomer. Of passing interest may be the Boötes Void, a 250 million light year-diameter void that despite its huge size only contains about 60 galaxies; and the Boötes Dwarf galaxy that was only discovered in 2006 because it is one of the faintest galaxies found to date.

Cancer

Cancer is by far the faintest of the 12 zodiacal constellations. One meteor shower, the Delta Cancrids has its radiant in Cancer, close to the star Asellus Australis. While his shower runs from the middle of December to the middle of February, a shower-within-a-shower occurs from the 1st of January to about the 24th of January, with a peak on the 17th of January. Note, however, that the Delta Cancrids rarely produce more that 4-6 meteors per hour at its peak.

– Quick Facts

Cancer• Constellation: Cancer
• Coordinates: Between latitudes +90° and -60°
• Best seen: Best seen at 21:00 (9 p.m.) Local Time during March.
• Brightest star: Al Tarf (Beta Cancri)
• Stars with planets: 17 stars with 30 planets between them
• Size: 31st largest constellation
• Area: 506 square degrees
• Neighbouring constellations: Lynx, Gemini, Canis Minor, Hydra, Leo, and Leo Minor

– Objects of Interest

Cancer contains two Messier objects – the Beehive Cluster (M44) and M67 (NGC 2682), with only the former of interest to amateur observers. The Beehive Cluster (Praesepe, Messier 44, M44, NGC 2632, Cr 189), located only about 570 light years away, is one of the closest and brightest open clusters to Earth, making it visible to the naked eye. The cluster contains at least 1,000 stars, of which about 30% are Sun-like stars, with the remainder being mostly red dwarfs.

Crater

Crater (“the Cup”) represents the drinking cup of the Greek deity Apollo. It is very faint constellation, and contains no stars brighter than 4th magnitude. One meteor shower, the Eta Craterids has its radiant in Crater, but note that it is best observed from the Southern Hemisphere

– Quick Facts

Crater• Constellation: Crater
• Coordinates: Between latitudes +65° and -90°.
• Best seen: Best seen at 21:00 (9 p.m.) Local Time during April.
• Brightest star: Delta Crateris
• Stars with planets: 8 stars with 1 planet each
• Size: 53rd largest constellation
• Area: 282 square degrees
• Neighbouring constellations: Leo, Sextans, Hydra, Corvus, and Virgo

– Objects of Interest

Although Crater contains several galaxies, including Crater 2, the Milky Way’s fourth largest satellite galaxy, all are fainter than 12th magnitude, which means that these objects are not visible with modest amateur equipment.

Hydra

Hydra represents the Lernaean Hydra that was killed by Heracles during his Twelve Labours. In some accounts however, the constellation is taken to refer to the water serpent the Crow blamed for his tardiness in fetching the deity Apollo a drink of water. Two meteor showers, the Alpha -, and Sigma Hydrids have their radiants in the constellation. The shower runs from about the 15th of January to the 30th, with a peak on the night of the 20th/21st of January. Look for the radiant close to the head of Hydra. The Sigma Hydrids runs from the first week in December to about the 15th, with a peak on the 12th of the month that usually produces only 3 – 5 meteors per hour. Look for the radiant close to the star Minchir.

– Quick Facts

Hydra• Constellation: Hydra
• Coordinates: Between latitudes +54° and -83°.
• Best seen: Best seen at 21:00 (9 p.m.) Local Time during April.
• Brightest star: Alphard (Alpha Hydrae)
• Stars with planets: 23 stars with 32 planets between them
• Size: Largest of the 88 recognised constellations
• Area: 1303 square degrees
• Neighbouring constellations: Antlia, Cancer, Canis Minor, Centaurus, Corvus, Crater, Leo, Libra, Lupus, Monoceros, Puppis, Pyxis, Sextans, and Virg

– Objects of Interest

The main two main objects of interest in Hydra are Messier 48 (M48, NGC 2548) and the Southern Pinwheel Galaxy (M83, NGC 5236). Located about 1500 light years away, Messier 48 is a magnitude 5.5 open cluster, making it an easy target for binoculars. In good seeing conditions under dark skies, the cluster can also be observed without optical aid. Meanwhile, the Southern Pinwheel Galaxy (Messier 83), so-named because of its striking resemblance to the Pinwheel Galaxy (M101) in Ursa Major, is the closest and brightest spiral galaxy ever discovered, and at a distance of only about 14.7 million light years presents a beautiful view through optical equipment..

Leo

Leo is associated with the Nemean lion, and according to old Greek mythology, was the lion Hercules killed during his 12 Labours. The constellation was first catalogued by the Greek astronomer Ptolemy in the 2nd century, along with the other 12 zodiacal constellations. Two meteor showers, the Leonids, and the January Leonids have their radiants in Leo. The Leonids usually peak on or around the 17th/18th of November each year, and radiate from a point close to the star Gamma Leonis, while the weak January Leonids peak in the first week of January.

– Quick Facts

Leo• Constellation: Leo
• Coordinates: Between latitudes +90° and -65°.
• Best seen: Best seen at 21:00 (9 p.m.) Local Time during April.
• Brightest star: Regulus (Alpha Leonis)
• Stars with planets: 16 stars with 28 planets between them
• Size: 12th largest constellation
• Area: 947 square degrees
• Neighbouring constellations: Ursa Major, Leo Minor, Lynx , Cancer, Hydra, Sextans, Crater, Virgo, and Coma Berenices

– Objects of Interest

Leo contains five Messier objects: Messier 65 (NGC 3623), Messier 66 (NGC 3627), Messier 95 (NGC 3351), Messier 96 (NGC 3368), and Messier 105 (NGC 3379). Note that all of the objects mentioned are galaxies that can generally not be observed with small telescopes, and usually require medium to large telescopes, as well as good seeing conditions.

Located about 35 million light years away, NGC 3628 is the most distinctive feature of this galaxy is the dark dust lane that obscures its spiral structure, since we see it exactly edge-on. The clearly visible distorted shape of the galaxy is the result of tidal interactions with M65 and M66, the other two members of the Leo Triplet Group of galaxies. One other major feature of NGC 3628 is a 300 000 light year-long tidal tail that is believed to have come about as the result of tidal interactions with other galaxies.

Messier 96 is located about 31 million light years away and spans across 100 000 light years, which makes it about as big as the Milky Way, and the largest member of the Leo 1 Group of galaxies. While it is classified as an intermediate spiral galaxy, the slight distortions in its spiral structure seen here are thought to be result tidal interactions with other massive objects that likely occurred in the distant past.

Virgo

Virgo contains the point at which the ecliptic crosses the celestial equator, known as the point of the Autumnal Equinox, which is close to the star Beta Virginis. The other (opposite equinox point is locate in the constellation Pisces.

A series of meteor showers, collectively known as the Virginids Meteor Shower, has its radiants in Virgo. Note however that the Virginids consists of several overlapping showers, including the Alpha Virginids, Gamma Virginids, Eta Virginids, Theta Virginids, Iota Virginids, Lambda Virginids, Mu Virginids, Pi Virginids, Psi Virginids, and March Virginids.

While the parent body/bodies of the (collectively-named) Virginids is not known, the entire complex of shower generally runs from January to may, with most peaking in March or April. Note also that most showers in the complex seem to radiate from Leo in January, the radiant steadily moves toward Virgo, which it reaches in May.

– Quick Facts

Virgo• Constellation: Virgo
• Coordinates: Between latitudes +80° and -80°
• Best seen: Best seen at 21:00 (9 p.m.) Local Time during May.
• Brightest star: Spica (Alpha Virginis)
• Stars with planets: 29 stars with 49 planets between them
• Size: 2nd largest constellation, after Hydra
• Area: 1294 square degrees
• Neighbouring constellations: Boötes, Coma Berenices, Leo, Crater, Corvus, Hydra, Libra, and Serpens Caput

– Objects of Interest

Virgo has 11 Messier objects: Messier 49 (NGC 4472), Messier 58 (NGC 4579), Messier 59 (NGC 4621), and Messier 60 (NGC 4649), Messier 61 (NGC 4303), Messier 84 (NGC 4374), Messier 86 (NGC 4406), Messier 87 (NGC 4486), Messier 89 (NGC 4552), Messier 90 (NGC 4569) and Messier 104 (NGC 4594, Sombrero Galaxy). Note that most of the galaxies listed above are members of large extended groups of galaxies, which in the case of the Virgo Cluster extend into the constellation Coma Berenices.

Found within the constellation is the Virgo Cluster, which contains between 1,300 and 2,000 galaxies, and forms the heart of the Virgo Supercluster of Galaxies, of which the Local Group of Galaxies is an outlying member. Another object of interest is the Sombrero Galaxy (M104, NGC 4594), which is a giant elliptical galaxy located about 29.3 million light years away that possibly contains a super massive black hole in its core. M104 is an easy target for small to medium amateur telescopes, and can be located about 11.5 degrees to the west of the bright star Spica.

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