Our Friendly Skies - April 2010

April 09, 2010|By ROD MARTIN / Brish Planetarium and ANDY SMETZER / Tristate Astronomers
  • April 2010 All-Sky Chart

Visible evening planets

Venus appears low in the west and sets within an hour of sunset.

Mercury is low in the west to the lower right of Venus.

Mars is visible high in the south at sunset.

Saturn is visible all night, in the east after sunset.

Visible morning planets

Saturn is visible in the west.

Jupiter is low in the east an hour before sunrise.

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

Antietam Battlefield public star party

Explore the night sky with the TriState Astronomers April 16 and 17 at the annual free public star party at Antietam National Battlefield in Sharpsburg. A variety of telescopes will be set up both nights near the Visitors Center parking lot. You will be able to view Saturn, our moon, and other wonders of the night sky.There will also be laser guided sky tours pointing out various stars, planetsand constellations.Observing starts at sunset until around 11 p.m. There is no admission charge. The event will be canceled if cloudy. For more information, call Dan at 301-988-9828.


Solar system

Two planets highlight the evening sky, while two others make a brief appearance after sunset.

Saturn is in the sky all night. It rises during evening twilight and sets around sunrise. Saturn can be found about halfway between the blue star Spica in Virgo and the back of Leo the Lion. It looks like a cream-colored dot against the background of stars. It is similar in brightness to the brighter nearby stars. To see the rings, at least 25 power is needed.

Mars is in the constellation Cancer and stands out in the region between Gemini and Leo. Look high in the south after sunset. Around the middle of the month, Mars passes near the Beehive star cluster in Cancer the Crab.

Mars is becoming dimmer and smaller in telescopes as Earth speeds away in our faster orbit.

Venus is the brightest planet in our sky. Only the sun and moon are brighter in our sky. It is very low in the western sky as twilight ends. Use it to help find nearby Mercury.

Mercury hides near the Sun most of the time, but reaches its best evening appearance for us the first half of April. It is low, only about 10 degrees high a half hour after sunset. Lucky for us, it will be easy to locate because it is very close to Venus this month. Venus will be to the upper left and very bright.Look for Mercury early in the month because it reaches inferior conjunction on April 28 when it passes between Earth and the sun.

Jupiter is emerging into the morning sky before sunrise. It may be seen low in the east as a bright star. It will get higher and better through the spring and into the summer. During April, Jupiter rises about one hour before sunrise and two hours by month's end.

The Lyrid meteors peak during the morning hours of April 22 and 23. These meteors are often fast and bright. They will be best observed after the waxing gibbous moon sets.

Sun and moon

Easter was on April 4 this year. The date of Easter is determined by the dates of the full moon, spring equinox and the following Sunday. Easter is determined as the first Sunday after the first full moon after the first day of spring. Spring is defined as March 21, regardless whether it is actually the 20th or 22nd.

In 2010, the first full moon of spring is March 28, so the following Sunday, April 4, was Easter. The date gets interesting in 2011. The full moon occurs March 19, two days before the equinox, so the next full moon determines the date.

That full moon is Sunday, April 17, so the following Sunday is April 24 for Easter. The latest possible date is April 25 and that will occur in 2038.

On April 1, the sun rose at 6:55 a.m. and set at 7:35 p.m., for 12 hours and 40 minutes of daylight. By April 30, the sun rises at 6:13 a.m. and sets at 8:04 p.m., for 13 hours and 51 minutes of daylight.

The sun enters the astronomic boundaries of Aries from Pisces on April 18.

The moon reached last quarter on April 6 and reaches new on April 14, first quarter on April 21 and full on April 28.

Brish Planetarium

The public program is "More than Meets the Eye." The program will be presented on Tuesdays through April at 7 p.m.

"More than Meets the Eye" shows how celestial objects really look through small telescopes and to the unaided eye as compared to the beautiful images from observatories.

Due to production problems, the originally scheduled program "New Horizons" will be postponed to the 2010-11 school year.

Programs are held Tuesday evenings at 7 p.m. when schools are in session, unless noted otherwise. If schools are closed all day or dismissed early due to inclement weather, that night's program is canceled.

Admission costs $3 for adults, $2 for children and students and senior citizens with a WCPS gold card are free.

Tristate Astronomers

The Tristate Astronomers meet monthly in the planetarium. For more information and schedules for the club, go to

The planetarium is at the Central Offices of Washington County Public Schools on Commonwealth Avenue off Frederick Street in Hagerstown.

For more information, go to, call 301-766-2898 or sende-mail to">

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