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Explore unique elements of isle skies in program

By Mike Shanahan

Bishop Museum

POSTED:
LAST UPDATED: 09:03 p.m. HST, Aug 05, 2011

Bishop Museum's newest planetarium program, Tropical Skies, is now playing at 3:30 p.m. daily (except Tuesdays, when the museum is closed).

Tropical Skies explores some of the unique qualities of the Hawaiian daytime and nighttime sky.

We use the planetarium sky to show the changes in the sun's path during different seasons. We look at the phenomenon of Lahaina Noon, that uniquely tropical event where the sun passes directly overhead. And we find the Southern Cross and discover why it is visible in Hawaii but not in the continental United States.

February Planets

Jupiter remains the bright light in the western evening sky, shining at minus 2 magnitude. However, it is getting pretty low in the west in February and we will lose it entirely in late March. At the start of February, look for Jupiter about one-third of the way up in the western sky at dusk. In early February, Jupiter sets just before 10 p.m. By the end of February, Jupiter is very low in the west at dusk (7:25 p.m.), only about 12 degrees above the horizon. You will have only an hour to catch Jupiter before it sets at 8:30 p.m. Look for the crescent moon next to Jupiter on Feb. 6 and 7.

Venus is that blazing light you see in the early morning sky throughout February. Venus rises about 4 a.m. at the start of February and at 4:30 a.m. at the end of the month. It remains a beacon in the eastern predawn sky all month. At minus 4 magnitude, it is the brightest dot in the sky. Look for the old crescent moon next to Venus on the mornings of Feb. 28 and March 1.

On the Net:

» For more information and a longer version of this article, go to www.bishopmuseum.org/exhibits/planetarium/planetarium.html

Saturn rises in the east at 11 p.m. at the start of February and by 9 p.m. at the end of the month. This means it will be high in the southeast by the time much-brighter Venus joins the planet show around 4 a.m. Shining around 0.5 magnitude, Saturn is just above Spica, a bluish star that is slightly brighter than Saturn brightness. Look for the waning gibbous moon next to Saturn on Feb. 20 and 21.

February Stars

In the east, Leo the Lion returns. By the time this star map is in effect (9 p.m. at the start of February, 7 p.m. at the end), nearly all of Leo is above the horizon, including the bright star Regulus.

In the south, look for the star Canopus. Called Keali'iokonaikalewa in Hawaiian, the "chief of the southern skies," Canopus is the second-brightest star in the entire sky. It's also a good example of a star we can see from Hawaii, but which never rises above the horizon in most of the continental U.S. Even from Hawaii, it is pretty low in the southern skies.

Look for Orion the Hunter high in the south, with its familiar hourglass shape, distinctive belt of three stars, and brilliant stars Rigel and Betelgeuse. Other winter constellations in the center of the map include Auriga the Charioteer, with its brilliant yellow star Capella.

Look also for the Gemini, marked by the twin bright stars Castor and Pollux; Canis Major, with its star Sirius, the brightest star in the sky; and Taurus the Bull, with the reddish Aldebaran marking its eye.

Also high overhead is Perseus the Hero, whose shape looks somewhat like a nightcap. The cluster of the Pleiades is at his feet. To the west of Perseus is Pegasus the Flying Horse, now on the western horizon.

The Little Dipper, with the North Star at the end of its handle, is as low as it ever gets. In fact, the Little Dipper (or officially Ursa Minor, the Little Bear) is the only one of the 88 official constellations that stays completely above the horizon all year round from Hawaii's latitude.

That said, the stars of the Little Dipper, except for the North Star, are so faint that they are usually hard to find. This is one reason why we try to find other pointers to the North Star.

The most common pointer to the North Star is the Big Dipper, which has been missing from our Hawaii evening sky these last few months. Fortunately it is just rising in the February evening sky. As you can see from the February star map, the cup of the Big Dipper is fully visible. The two stars in the cup that don't have the handle attached are the pointer stars, and can be used to find the North Star.

The constellation of Cassiopeia is on the other side of the North Star from the Big Dipper and is now low in the southwest. Usually you see either the Big Dipper or Cassiopeia, but here in the February evening sky you can catch them both. Cassiopeia is made up of five stars that form a squished "W" shape. The three middle stars of Cassiopeia's "W" form an arrowhead that points roughly to the North Star. When the Big Dipper isn't visible, Cassiopeia is another way to locate the North Star.

The Southern Cross is missing from the evening sky. You need to search the morning skies in February to find it. It rises in the southeast at 2 a.m. in early February, and by midnight at the end of the month. Look low in the south for the Southern Cross; you need to make sure there are no buildings or trees blocking the southern horizon. Its bottom star, Acrux, gets only about six degrees above the horizon at its highest point, or the width of two fingers at arm's length. The Cross is due south at 4:15 a.m. at the start of February and 2:15 a.m. at the end. Look for the bright stars Alpha and Beta Centauri to the left of the Southern Cross; this can be your guide to point to the Cross itself.

Mike Shanahan is the director of education, exhibits and planetarium at Bishop Museum. He can be reached at mikes@bishopmuseum.org.

 






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