By Vinita Domier

Everyone is invited to the Davis Astronomy Club meeting at 7:30 p.m. Saturday at Explorit, 3141 Fifth St. You don’t have to pay any dues to be a member of the Davis Astronomy Club. If you are interested in astronomy, you’re welcome to attend. Telescope viewing will be available after the presentation.

This month, we will discuss the Summer Triangle. As the name implies, it is an almost right triangle overhead in the summertime night skies. It is easy to discern in the sky with the naked eye as there are three very bright stars conveniently located at the vertices of this vast triangle in a vicinity that lacks other bright stars.

The three stars, (Vega, Altair and Deneb) are the brightest stars in their respective constellations (Lyra, Aquila and Cygnus). Together, the three stars form the asterism (grouping of stars) known as Summer Triangle. It rises in the east at dusk, is overhead at midnight and sets in the west at dawn in the summer months.

Vega, in the constellation Lyra (the Harp), is the brightest of the three stars and also the first to be visible above the horizon. It is a blue-white main sequence star, the fifth brightest star in the night sky and third brightest in the Northern Hemisphere.

Vega is the bright star above the small parallelogram that makes up the Lyra constellation. Vega is at the right angle of the Summer Triangle. Due to precession of the Earth’s axis, Vega was our North Star in 1200 BCE. Polaris is our North Star now, but Vega will be our North Star again in 14000 CE.

Altair, in the constellation Aquila (the Eagle), is the second brightest of the three stars and the second to be visible above the horizon. It is a yellow-white main sequence star, the 12th brightest star in the night sky and eighth brightest in the Northern Hemisphere. Altair is the bright star in the head of the eagle that makes up the Aquila constellation.

Deneb, in the constellation Cygnus (the Swan), is the least bright of the three stars and the last to be visible above the horizon. It is a white supergiant star, the 19th brightest star in the night sky and 14th brightest in the Northern Hemisphere.

Deneb is the bright star in the tail of the swan that makes up the Cygnus constellation. Deneb also forms part of the Northern Cross — an asterism, which is a recognizable pattern within a constellation. Some of the bright stars in Cygnus combine to make the Northern Cross pattern.

Another celestial feature of the Summer Triangle is that the Milky Way, the pale cloud band, passes right through the Summer Triangle between the stars Vega and Altair. This luminous cloudy river in the sky is visible in a fairly dark sky away from city lights, extending across the night sky. It is worth the effort to go to a rural area to view this heavenly wonder in the summer night sky.

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Explorit’s coming events:

* Summer Camp through Aug. 19: Several spaces are still available in the pre-K/kindergarten and first-/second-grade sections of Explorit’s Summer Science Camp. For information about openings, visit http://www.explorit.org/camp or call (530) 756-0191 between 9 a.m. and 4:30 p.m. Monday through Friday.

— Explorit Science Center’s 3141 Fifth St. site is the location for field trips, programs for groups, astronomy club meetings and Summer Science Camp. It is also the hub for Explorit’s traveling programs that reach an 18-county region. The site is open to the public for special events and to groups by reservation. For more information, call (530) 756-0191 or visit http://www.explorit.org

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