Categorized | Sci-Tech

Sky Watch: Jupiter lighting up February skies

(Sky Watch is a regular column written by Mike Shanahan, director of education and exhibits at the Bishop Museum in Honolulu. He can be reached at mikes@bishopmuseum.org.)

Jupiter remains the bright light in the western evening sky, shining at minus 2 magnitude. However, it’s getting pretty low in the west in February and we’ll 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, the planet 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 8:30pm.

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.

Saturn rises in the east at 1:11 p.m. at the start of February and by 9pm 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.

Mars and Mercury are lost in the sun all month.

Stars

The map for February 2011 is good for 9 p.m. at the start of February, 8 p.m. in the middle of the month, and 7 p.m. at the end of the month. As always, hold this map over your head or the four directions will never line up!

In the east, Leo the Lion returns. By the time this star map is in effect (again 9 p.m. as 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, looks for the star Canopus. Called Kealiiokonaikalewa 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 US. Even from Hawaii it’s pretty low in the southern skies.

Look for Orion the Hunter very high in the south, with its familiar hour-glass shape, distinctive belt of three stars, and brilliant stars Rigel and Betelgeuse. A modern Hawaiian term for the constellation is Ka hei hei on na keiki, or “the children’s cat’s cradle.”

Other winter constellations in the center of the map include Auriga the Charioteer, with its brilliant yellow star Capella. The term Hokulei (“lei of stars”) is applied both to the star Capella and to the constellation Auriga as a whole.

Look also for the Gemini, marked by the twin bright stars Castor and Pollux; and for Canis Major, with its star Sirius (Aa in Hawaiian, the fire star), 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 (in Hawaiian “Makalii” or “Little Eyes”) 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’re usually hard to fund. 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 starmap, 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.

Stars that aren’t on the map:

The Southern Cross is also 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.

In Hawaiian the Southern Cross is called Hanaiakamalama, which means “cared for by the moon.” Look very low in the south for the Southern Cross; you need to make sure there are no buildings or trees blocking your south horizon.

Its bottom star, Acrux, only gets about six degrees above the horizon at its highest point, or the width of two fingers at arms 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.

By the very end of February, look for all of Scorpius in the morning sky. Called Ka Makau Nui o Maui in Hawaiian, or “Maui’s Big Fishhook,” this constellation blazes brightly in the southeast at 5 a.m. at the start of February and 3 a.m. by the end of the month.

Moon phases
New Moon: Feb. 2
First Quarter: Feb. 10
Full Moon: Feb. 17
Third Quarter: Feb. 24

— Find out more:
Bishop Museum Planetarium: www.bishopmuseum.org/exhibits/planetarium/planetarium.html
Hawaiian Astronomical Society: www.hawastsoc.org/

2 Responses to “Sky Watch: Jupiter lighting up February skies”

  1. Michele Nobriga says:

    Thank you for a great article! I am a volunteer at the Mauna Kea Visitor Information Station and I will be taking a copy with me tomorrow night to share with our guests.

    Aloha

    MN

  2. Lighting says:

    Really good weblog, keep me from checking it, I will be seriously interested to know more about it.

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