WHERE: AT EXPLORIT Science Center, 3141 5th Street, Davis.

Deep Sky Objects
Saturday, September 10, 2005
7:30 to 9:30 p.m. at Explorit
Hosts: Vinita & Calvin Domier (530) 756-0191, vcdomier@yahoo.com

Join us Saturday, September 10th starting at 7:30 p.m. for a discussion on deep sky objects. We will also have telescopes set up to look at the night sky. This program is free for all ages.

After the initial thrill of viewing the craters of the Moon, the rings of Saturn, the moons of Jupiter, etc., through their small telescopes, many backyard astronomers want to see deep space objects like the Orion Nebula, the Andromeda Galaxy, Crab Nebula, etc.

Quoting Wikipedia (an online encyclopedia): "Deep sky object (DSO) is a term used often in amateur astronomy to denote objects in the night sky other than solar system objects (such as planets, comets, and asteroids), single stars and multiple star systems." Most DSOs are not visible with the naked eye, but can be seen with a small telescope or good binoculars. There are four main types of DSOs:

(1) Star Clusters are group of stars that are bound together by gravity. Globular clusters are compact spherical groups of 10,000 - millions of old stars 10-30 light years across. Open Clusters are loosely bound groups of few hundred young stars about 30 light years across.
(2) Nebulae are interstellar clouds of dust and gasses. Diffuse or Bright nebulae are emission nebulae with glowing ionized gas clouds, and reflection nebulae lit by nearby stars' lights. Dark nebulae can be detected only when they obscure other stars and nebulae. Planetary nebulae are the outer gaseous layers ejected from old dying stars.
(3) Galaxies contain 10 million -1 trillion stars, interstellar gas and dust, (and dark matter and energy), all orbiting a common center of gravity. There are elliptical, spiral, and irregular galaxies.
(4) Quasars are the brightest objects in the universe with very high red shifts, indicating that they are very distant objects emitting very high energy levels.

Charles Messier, an avid comet hunter, put together a list of DSOs so astronomers would not confuse them with comets. His final 1791 list had 110 DSOs, ranging from M1 to M110, which are now known as Messier objects. As Messier did his observing in Paris, France, his list does not include DSOs visible beyond a latitude of -35_S.

The New General Catalogue (NGC) is the most comprehensive catalog of 8000 DSOs known as NGC objects. It was initially compiled in 1880s by J.L.E. Dreyer using William Herschel's observ-ations. It was expanded with two Index Catalogues (IC I and IC II) using John Herschel's observations in the Southern Hemisphere. This Revised New General Catalogue has eliminated many errors found in the original NGC.

All 110 Messier objects are known by their Messier number and by their NGC number. Some DSOs also have names. Andromeda Galaxy is M31 and NGC 224. Crab Nebula is M1 and NGC 1952. Hercules Cluster is M13 and NGC 6205. Orion Nebula is M42 and NGC 1976. Beehive Cluster is M44 and NGC 2632.

It is possible to see all 110 Messier objects (relatively bright DSOs) in one night. Messier marathons are possible close to 25_N latitude near the Spring Equinox (late March or early April). The DSOs have to be viewed in prescribed order, starting in the west at sunset and finishing in the east at sunrise.

In addition to observing some DSOs, we will look at Jupiter (mag. -1.6) and Venus (mag. -3.9). Both are in Virgo, setting around 9 pm. On 9/6 evening, there will be a spectacular alignment of Venus (left), Jupiter (right) and the crescent Moon (below). Mars (mag. -1.0 in Aries) rises at 10:30 pm and Saturn (mag. +0.3 in Cancer) rises before dawn.

Moon phases:
New: 9/3 & 10/3,
First Qrt: 9/11 & 10/10,
Full: 9/17 & 10/17,
Last Qrt: 9/24 & 10/24.

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.