Skies Over Louisville: Spring 2010 (March 21, 2010 - June 21, 2010)

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Skies Over Louisville Spring Schedule at the Planetarium

Interested in seeing the sping sky in action, complete with tour guides and constellation tales? Join us for Skies Over Louisville, our monthly, live star program at the planetarium. Always on Saturday night at 9 PM, the dates for the spring 2010 editions are March 13, April 10 and May 8. After the show, enjoy a telescope viewing party on the planetarium terrace with Louisville's own Astronomical Society (the telescopes are weather permitting, but the Skies Over Louisville show happens rain or shine!)

Louisville's Spring Skies

As we move into the winter months, longer nights and frigid temperatures mean perfect stargazing opportunities if you bundle up tight and bring the hot chocolate. The full moons during the winter have names which seems to describe the season; the Cold Moon, on December 2nd, signals the longest and darkest nights of the year; January's Wolf Moon is named for the packs that would gather around Native American villiages looking for food at this time of the year; and the Snow Moon of February describes the month that usually saw the heaviest snowfall for the Native Americans. See below for dates and special Moon happenings this season.

Spring Planets

On the Solar System front, here is what to expect from our planetary neighbors this month:

Venus

The brightest object in the night sky except for the Moon, Venus is not hard to find, even in city lights. It is so bright, in fact, that you can observe its phases as its position changes in the sky throughout the month.

April 2010: Venus appears low in the western sky near the horizon just before sunset at around 9 PM

May 2010: Venus is up slightly longer in the west setting around 11 PM

Mars

Known as the red planet for its ruddy appearance, Mars is the closest planet to Earth and has long been the stuff of science fiction novels for harboring extraterrestrial life. Using a telescope or a pair of binoculars, one can see the ice caps that adorn the planet's poles. These ice caps give astronomers hope that Mars could be a potential cradle for life.

April 2010: Mars is high overhead in the skies this month in the constellation Cancer and is visible throughout the evening

May 2010: Mars remains high in the sky for the month of May as well, moving away from Cancer and edging closer to the constellation Leo

Jupiter

Jupiter is the largest planet in the solar system; its cloud tops act like a giant mirror, reflecting much of the sunlight that falls onto them. Some of this reflected light makes its way back towards the Earth, making Jupiter appear as one of the brightest objects in the night sky. Through a good pair of binoculars it is possible to see the four largest moons of Jupiter, Io, Europa, Ganymede, and Callisto.

April 2010: Jupiter begins to rise in the morning about an hour before sunrise around 6 AM

May 2010: Jupiter rises in the east around 5 AM and can be seen shining brightly for a couple of hours before sunrise

Saturn

Saturn, the second largest planet, is mostly composed of hydrogen and has a density less than that of water. That means, if you had a bathtub large enough, Saturn would float! This sixth planet from our Sun also contains a system of rings that span about 100,000 miles and are made of various sizes of ice and rock. These rings truly distinguish Saturn from all the other planets in the solar system and make it a favorite target for binoculars and small telescopes.

April 2010: Saturn dominates the sky in the constellation Virgo and can be seen throughout the night

May 2010: Saturn remains in the constellation Virgo during the month of May and can be easily seen as one of the brightest objects in the night sky

The Spring Constellations

Ursa Major and Ursa Minor

One of the most recognizable objects in the night sky is not a constellation at all, but a group of stars called an asterism that form part of a larger constellation. The Big Dipper is marked by three bright stars that form a handle and four stars which make the shape of a bowl. The two outside stars of the bowl can be used to find a star named Polaris, which is known as the North Star because it remains fixed in the northern skies.

Polaris is itself part of an asterism known as the Little Dipper and when we look at the larger constellations the dippers are part of, we see the great and small bears known as Ursa Major and Ursa Minor. These constellations are circumpolar meaning they lie closely to the North Star and never really set throughout the night. In fact, because they never go below the horizon, you can enjoy these constellations throughout the year.

Finally, several bright galaxies and astronomical objects inhabit this part of the sky including the Pinwheel Galaxy, the Cigar Galaxy, and the Owl Nebula.

Bootes

The handle stars of the Big Dipper arc backwards to the third brightest star in the night sky known as Arcturus in the kite-shaped constellation Bootes, the herdsman. While Greek mythology attributes the development of the plow to him, Bootes also hosts a Sun-like star with an exoplanet, tau Bootes, which can be found in the tail of the kite this constellation resembles.

Virgo

From Arcturus we can "spike" down the sky to Spica, a blue giant star in the constellation Virgo, the maiden. Used by the ancient Greeks as a way to indicate the beginning of spring, Virgo is also one of the constellations of the zodiac. This means the ecliptic, the path the Sun takes over the course of one year, lies in this constellation and that, during some months of the year, the Sun travels through this part of the sky. So, if you were born during the months of September or October, the time when the Sun is traveling through this constellation, your sign of the zodiac would be Virgo. Other zodiacal constellations in the skies this season are Leo and Cancer.

One of the most remarkable features we can see in Virgo is a large supercluster of galaxies, appropriately called the Virgo Supercluster. This supercluster is the group with which our own Milky Way Galaxy is gravitationally associated. Additionally, there are several beautiful galaxies that you can view with a small telescope.

Taurus

Taurus the bull lies just to the right of Orion in the winter skies and, in reality, is not a bull at all, but merely a disguise used by the god of all gods in Greek mythology, Zeus, to woo a beautiful Phoenician princess named Europa. Two open clusters of stars make great targets for binoculars or a small telescope. The first of these is the Hyades which can be seen arranged in the shape of a V and compose Taurus' head. The brightest star in Taurus, Aldebaran, lies within this group. The other open cluster, also called "The Seven Sisters," is the Pleiades, and is easily found lying along the bull's back.

Corona Borealis

Next to Bootes, we find a group of stars arranged in the shape of a letter C. This is the constellation Corona Borealis, the Northern Crown. This was a crown placed on the head of a princess, Ariadne, for helping her love, Theseus, through a labyrinth after he defeated a minotaur at the maze's center. Corona Borealis contains several variable stars which are stars whose brightness seem to change over time.

Leo

The back two stars of the bowl of the Big Dipper can be used to find the bright star Regulus in the constellation Leo, the lion. Leo was a fierce and greatly feared beast who was slain by the Greek hero Hercules as the first of his 12 challenges. Regulus, the brightest star in Leo is actually a system of stars all under the same name. This part of the sky contains several bright Messier objects (M65, M66, M95, and M96) as well.

Cancer

The constellation Cancer is a faint constellation that is meant to resemble a small crab which was used by the goddess Hera to try and distract Hercules from his twelve labors, but to no avail. To honor the crab's honorable, but pitiful, performance, Hera placed him in the sky with dim stars. Nevertheless, Cancer hosts one of the most impressive sights of the season, the Beehive cluster, which is a group of young stars that have formed from the same parent cloud. It is one of the nearest clusters to us and can be found in the center of the crab's shell. A pair of binoculars will reveal even more stars and some faint nebulosity or cloudiness.

Special Events in the Sky this Season

April 2010

The constellation Leo is host to the second largest asteroid in the asteroid belt, Vesta. It will remain Leo (near his mane) for the months of April and May. It makes a great target for a small telescope.

Additionally, the Lyrid meteor shower will appear during the early morning hours in the constellation Lyra, the Lyre. The shower will peak on the nights of April 21st and 22nd.

May 2010

The Eta Aquarids can be seen in the constellation Aquarius beginning around 3 AM. The shower will be at its most impressive on May 5th.

To Ask the Astronomer a question, send your email to planet @ louisville.edu.
To listen to the Sky hotline, call 502-852-6664 and press 4 for the Sky this Month.