Our Friendly Skies - October 2009

September 30, 2009|By ROD MARTIN / Brish Planetarium and ANDY SMETZER / Tristate Astronomers

Visible evening planets

Jupiter is visible all evening.

Visible morning planets

Venus is very bright in the east before sunrise.

Mercury is visible the first half of the month.

Mars is high in the southeast.

Saturn rises shortly before the Sun.

For more information about the visible evening planets and nighttime sky, download the planetarium's podcast "Skylights" from

Star party

Celebrate the International Year of Astronomy with the TriState Astronomers. On Oct. 16 and 17, the autumn version of the free public star party at Antietam National Battlefield will be held.

This will be on both nights from sunset to 11 p.m.

One of the objectives of the International Year of Astronomy is to enable as many people as possible, especially children, to look at the sky through a telescope and gain a basic understanding of the Universe.


Telescopes will be set up both nights near the visitors center parking lot for all to view the wonders of the autumn night sky. View Jupiter and 4 of its amazing moons, just like Galileo did 400 years ago. You'll be able to view the sky through a variety of telescopes,throughout the evening. Bring your own telescope or binoculars if you wish. Laser guided tours of the stars and constellations found in the autumn night sky will also be held. This is an ongoing event for the whole family. The event will be canceled if cloudy. For more information, call Dan at 301-988-9828 or go to

Solar System

The brightest planet in the evening sky is Jupiter. Jupiter is bright at -2.6 magnitude in the faint constellation Capricornus. It is easy to observe its disc and four bright satellites with a good pair of binoculars if you hold them very steady.

The four bright satellites were discovered by Galileo 400 years ago and are called the Galilean Moons. Because of this discovery which revolutionized astronomy, 2009 has been designated as the International Year of Astronomy. Since the moons orbited an object other than the Earth, the geocentric or Earth-centered model of the solar system was disproved and allowed acceptance of the Copernican Sun-centered solar system model. See below for information about an exciting IYA event coming in November.

Neptune is east or left of Jupiter. Neptune is tough to see at +7.9 magnitude. You will need a small telescope or good binoculars to see its grayish disc.

The morning sky is much more exciting than the evening sky. Several planets are visible before sunrise.

Venus is the brightest morning planet slightly below -4 magnitude. It is now dropping toward the Sun as October passes. On Oct. 13, it passes about one half degree south of Saturn in the morning twilight.

Mercury has emerged from passing between the Earth and Sun and is putting on its best morning display of 2009. It appears fartherest from the Sun on Oct. 6 at greatest western elongation. Then it passes about one third of a degree from Saturn on Oct. 8.

Saturn is now a morning planet. It is low in Virgo and rises shortly before the Sun. It will get better throughout the fall and winter.

Mars is climbing higher in the morning sky as it moves through Gemini into Cancer. It is getting brighter at +0.5 magnitude, becoming about as bright as nearby stars. Its color helps identify it.

Sun and Moon

Since we have passed the fall equinox on Sept. 22, the Sun rises later and sets earlier with less than 12 hours of daylight. This dreary trend will continue through the winter solstice in December until the next equinox which marks the beginning of spring in March.

On Oct. 1, the Sun rises at 7:07, sets at 6:53 for 11 hours and 46 minutes of daylight. By Oct. 31, the Sun rises at 7:39, sets at 6:10 for 10 hours and 31 minutes of daylight.

The Sun enters the astronomical boundaries of Libra from Virgo on Oct. 30.

The Moon reaches full on Oct. 4, last quarter on Oct. 11, new on Oct. 18, and first quarter on Oct. 26. This month's full moon is the "Harvest Moon." This is the full moon that occurs closest to the fall equinox. This moon seems to rise as the Sun sets then sets as the Sun rises providing extra light for work.

Brish Planetarium and events

Public planetarium programs will resume Oct. 20 with "Planets." This is a change from the original published date of Oct. 6. This program talks about the objects of our solar system as well as planets around other stars. The programs will be held Tuesdays at 7 p.m. Admission costs $3 for adults, $2 for children and students, and senior citizens with a WCPS Gold Card are free.

Celebrate the International Year of Astronomy with the Brish Planetarium and the Discovery Station in downtown Hagerstown on Saturday, Nov. 14. The event will consist of portable planetarium programs, talks by members of the Tristate Astronomers, displays in Discovery Station, and the main event which is the unveiling of NASA Great Observatory images of the center of the Milky Way.

This image unveiling is part of the worldwide release of these images from NASA's Chandra, Hubble and Spitzer space observatories. About 150 locations around the United States were chosen for this honor.

The planetarium is at the Central Offices of the Washington County Public Schools on Commonwealth Avenue off Frederick Street in Hagerstown. The planetarium's Web site is For more information about schedules and special events, go to

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