Saturday: Cygnus the swan flies tonight. Deneb, the brightest star in the constellation, whose name means “tail” in Arabic, is two fists held upright and at arm’s length above due northeast at 10:15 p.m. Cygnus’ wings make a vertical line one half a fist to the right of Deneb. Its head, marked by the star Albireo, is two fists to the right of Deneb. While Deneb is at the tail of Cygnus, it is at the head of the line of bright stars. It is 160,000 times more luminous than the Sun, making it one of the brightest stars in the galaxy. It does not dominate our night sky because it is 2,600 light years away, one of the farthest naked eye stars. If Deneb were 25 light years away, it would shine as bright as a crescent moon. Compare that to Vega, its fellow Summer Triangle star. Vega IS 25 light years away and certainly doesn’t rival the light of the crescent Moon. Vega is about two fists to the upper right of Deneb.
Sunday: The bright red giant Antares is about one fist above
the south-southeastern horizon at 11:00 p.m.
Monday: Altair, the lowest star in the Summer Triangle, is
one fist above due east at 11:00 p.m.
Tuesday: Jupiter is a little more than a half a fist to the
left of the moon at 9:30 p.m., just above the northwestern horizon.
Wednesday: Stonehenge was created on the island of Great
Britain by Neolithic people. “Manhattanhenge” was created on the island of
Manhattan by modern day architects and construction workers. Twice a year, at
the end of May and mid-July, the setting Sun aligns perfectly with the
Manhattan grid pattern. That means observers will see the Sun set at the end of
the street. The first Manhattanhenge sunset is tonight at 8:13 p.m. Eastern
time and then again tomorrow at 8:12 p.m. Eastern time. For more information
about Manhattanhenge, go to https://www.amnh.org/research/hayden-planetarium/manhattanhenge.
Thursday: As the weather warms up, people start thinking
about swimming in a nice cool body of water. A few years ago, astronomers
discovered evidence of an ocean about 20 miles beneath the surface of Saturn’s
moon Enceladus. NASA’s Cassini probes measured variations in how the moon’s
gravity pulled on the orbiting spacecraft. These variations can be explained by
a large amount of liquid water under one section of the ice because liquid
water is denser than an equal volume of ice. More recently, scientists have
discovered organic molecules in the geyser streaming out of cracks in the
surface. Now they hypothesize that the organic molecules come from hydrothermal
vents, similar to those found under Earth’s oceans, and are working on
discovering the creation mechanism. For more information about these, go to https://www.universetoday.com/166987/linking-organic-molecules-to-hydrothermal-vents-on-enceladus/.
While you need a very large telescope to see Enceladus, you can see Saturn at
4:15 a.m., one and a half fists above the southeastern horizon. The very bright
Venus is about a half a fist above the eastern horizon at this time.
Friday: The Beehive Cluster is about a half a fist to the
left of the moon at 10:00 p.m. two and a half fists above the western horizon.
The Beehive Cluster, described by Ptolemy as “a nebulous mass in the breast of
Cancer [the crab],” is an open star cluster of about 350 stars that is about
600 light years away.
The positional information in this column about stars and
planets is typically accurate for the entire week. For up-to-date information
about the night sky, go to https://nightsky.jpl.nasa.gov/planner.cfm.
All times are Pacific Time unless noted.
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