Tag Archives: Eridanus

Fornax (The furnace)

Constellation FornaxFornax, the furnace, is a southern constellation that barely comes into view for observers at 40-degrees north latitude. It is south of Cetus, and flanked by Eridanus and Sculptor. It reaches its highest point in the sky at nightfall in January, but its dim stars and placement at only ten degrees above the horizon make this a very challenging constellation. The view beyond Fornax’s foreground stars is out of the plane of the Milky Way Galaxy. This accounts for the paucity of visible stars in this region, and is why it was chosen for one of the Hubble Deep Field photographs. This also explains why a relatively large number of the dwarf galaxies in the Milky Way’s galactic halo can be found in this direction with a telescope.
http://en.m.wikipedia.org/wiki/Fornax

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

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

Eridanus (The river)

Eridanus was the ancient Greek name for today’s Po River. This constellation was one of the 48 constellations cataloged by the 2nd century astronomer Ptolemy that remain among the 88 modern constellations. This southern constellation has the distinction of being sixth largest of the modern constellations, and is best seen at its highest nightfall ascension in January. The river begins near Orion’s left foot and flows southward from there. At our 40-degree north location, the southern, or lower half of the constellation remains hidden below the horizon. At the southern end of Eridanus is the magnitude 0.5 star Achernar whose traditional name means “the river’s end.”

Of particular interest in this constellation is the Eridanus Supervoid. Numerous galaxies can be seen in deep exposure photographs in almost every direction when looking outward into the Universe beyond the foreground Milky Way stars, but the sky in the direction of Eridanus is almost entirely void of distant galaxies.
http://en.wikipedia.org/wiki/Eridanus_(constellation)

597px-Eridanus_IAU.svg
IAU Eridanus chart, IAU and Sky & Telescope magazine (Roger Sinnott and Rick Fienberg), June 5, 2011

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

Cetus (A sea monster in Greek mythology)

CetusCetus, the Greek mythological sea monster, is a large southern constellation on the celestial equator, and one of the 48 constellations cataloged by 2nd century astronomer Ptolemy. It is accompanied by other water constellations – Pisces, Aquarius and Eridanus. Its head is nestled among three zodiacal constellations: Taurus, Aries and Pisces. Its body is south (below) Pisces, and is flanked by Aquarius and Eridanus. Cetus’ close proximity to the ecliptic means that the Moon, planets and asteroids occasionally pass through this constellation. Cetus is placed highest in the sky at nightfall in December.

Cetus is home to one Messier object, M77, a striking face-on spiral galaxy. Among Cetus’ stars is an unusual variable star, the disappearing  one, or Mira (Omicron Ceti). This star’s high variability from 3rd magnitude to 10th magnitude means that it disappears from view when it dips below 5th or 6th magnitude. Cetus’ brightest star Menkar (Alpha Ceti) marks the sea monster’s nose.
http://en.wikipedia.org/wiki/Cetus

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

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