WHERE: AT EXPLORIT Science Center, 3141 5th Street, Davis.
(530) 756-0191

Orion Constellation!
Saturday, January 6, 2007
from 7:00 – 9:00 p.m. at Explorit (5th St.)
Hosts: Vinita & Calvin Domier (530) 756-7443, vcdomier@yahoo.com

Join us Saturday, Jan. 6th, at 7:00 p.m., at Explorit’s 5th Street site, to discuss the Orion constellation. In addition, we will discuss some of the deep sky objects found within the boundaries of the constellation. We will also use telescopes to look at objects in the night sky, weather permitting.

The Orion constellation is one of 88 constellations formally recognized by the International Astronomical Union. It is the second most identifiable star grouping in the sky (after the Big Dipper) due to its distinct pattern of bright stars, and is visible throughout the world as it lies on the celestial equator close to the Milky Way. For northern latitude observers, Orion is prominently visible in the night sky from late fall to early spring.

The Orion constellation, named after the Greek mythological character Orion, is also known as the Hunter as the bright stars in the constellation look like a hunter with one raised arm and one outstretched arm. Its most recognizable feature is three stars in a straight line in the middle of the star pattern, forming the hunter’s belt. Fainter stars form the hunter’s sword hanging from his belt.

The bright stars that make up the Orion constellation form a very clear star pattern. The stars also help locate nearby bright stars and their constellations. The main stars are:
• Betelgeuse (Arabic for armpit) is a very bright variable red giant star forming Orion’s right shoulder. This dull red star’s brightness varies from mag. +0.4 to +1.3. It is the ninth brightest star in the sky, and is part of the Winter Triangle along with stars Sirius and Procyon.
• Rigel (Arabic for foot) is a very bright blue-white giant forming Orion’s left knee. It is the brightest star in the Orion constellation with mag. +0.08, and it is a visual binary. It is the sixth brightest star in the sky, and is part of the Winter Hexagon, along with stars Sirius, Procyon, Pollux/Castor, Capella, and Aldebaran.
• Bellatrix (Latin for female warrior) and Saiph form Orion’s left shoulder and right knee, respectively.
• Alnitak, Alnilam, and Mintaka are the three stars (from left to right) in a line that forms Orion’s belt. Mintaka (Arabic for upper end of girdle) is a visual binary.

The belt stars point left to the brightest star in the sky, Sirius (in Canis Major), and point right towards Aldebaran (in Taurus). The two shoulder stars point left to Procyon (in Canis Minor). An imaginary line from Rigel to Betelgeuse points to twin stars Castor and Pollux (in Gemini).
There are many nebulae within the Orion constellation in the Orion Molecular Cloud Complex. This stellar nursery is only 1,500 light years from Earth and hundreds of light years across, making it the closest region of star formation.

Two most notable ones are:
• Orion Nebula (M42) is the fuzzy middle “star” of the three fainter stars that form Orion’s sword hanging from his belt. This beautiful greenish diffuse nebula is one of the brightest nebulae in the sky. It is 30 light years across and visible to the naked eye. Trapezium is an open cluster of young stars within the Orion Nebula. Four stars are visible in low power telescopes, two of which are visual binaries.
• Horsehead Nebula (IC 434) is a dark nebula located just below Alnitak (in the belt) and is only 3.5 light years across. This beautiful star nursery is a swirling cloud of dark dust and gases shaped like a seahorse surrounded by ionized gasses.

Sky Info for January 2007

Venus (mag. –3.8 in Cap.) sets soon after sunset ~6pm. Saturn (mag. +0.2 in Leo) is a bright planet in the night sky, rising ~8:30pm. Saturn is approaching opposition on Feb. 10. Jupiter (mag. –1.6 in Oph.) is a bright planet rising ~5am. Mars (mag. +1.5 in Sgr.) rises ~6am.

Moon phases: Full: 1/3, Last Qrt.: 1/11, New: 1/18, First Qrt.: 1/25.

Earth is at perihelion (closest to the Sun) on Jan. 3rd. Winter Solstice was on 12/21/2006.

*Free download of monthly sky maps and calendars available at www.skymaps.com.

To Receive These Bulletins via E-mail Contact Explorit at: Explorit Science Center

The Astronomy Club is for everyone - adults, children, knowledgeable or ignorant. Come to listen, look and learn, or to share your expertise or experience.