I was recently asked why the moon goes through phases – from crescent, to first quarter, to gibbous, to full and then back. They thought the Earth’s shadow was causing this.

As the moon orbits the Earth in a little over 28 days, we see a different perspective each day. The light we see on the moon comes from the sun. Because of this we see a little more of the illuminated part of the moon each night before the full moon and we see a little less after the full moon.

To visualize this take a ball outside on a sunny day and hold it out in front of you. Now spin around in a circle while holding the ball and watch the shadow change as you spin. You are the Earth and the ball is the moon.

Half of the moon is always illuminated by the sun. When the moon is opposite the sun, we see a full moon. When the moon is between the Earth and the sun, we see the “dark side.”

体育在线365When the Earth is directly between the moon and the sun, we have a lunar eclipse. Then we can watch the shadow of the Earth move across the moon.

We don’t have lunar eclipses every month because the moon’s orbit is tilted taking it above or below the Earth’s shadow.

Morning sky: Three planets dominate the morning: Mars, Jupiter, and Saturn. As the month begins, Mars leads the pack but by the end of March, Mars will be the last to rise. All three planets rise about 2 to 3 hours before the sun. Watch as Mars passes both Jupiter and Saturn.

Evening sky: Brilliant Venus is the brightest object (beside the sun and the moon) in the west. Watch Venus as she climbs higher in the sky.

Feb 28th: TAS’ First Quarter Moon observing at Cascades Park near the DOT building parking lot. Starts around 7 p.m. until 9 p.m. weather permitting.

1st: Mars, Jupiter, and Saturn form line in early morning sky.

7th体育在线365: Tallahassee Astronomical Society’s free ($1 donation suggested) planetarium show at the Downtown Digital Dome Theatre and Planetarium at the Challenger Learning Center (not recommended for children under 5). Doors close at 10 am sharp so get there between 9:30 a.m. to 9:45 a.m. Seating is limited. “March Skies over Tallahassee” will be repeated at 11 a.m. for a reduced planetarium price of $3.00 for children or adults and free for Challenger members.

8th: Daylight-saving time: “spring ahead” an hour.

16th: TAS monthly meeting at the Challenger Learning Center planetarium. Begins at 6:30 p.m.

18th: Moon, Mars, and Jupiter close together.

19th: Spring arrives.

20th:体育在线365 Mars and Jupiter close together.

21st体育在线365: Moon near Mercury in morning sky. You’ll need optical aid the see Mercury.

24th: Venus furthest from the Sun – 46 degrees. That’s 92 full-Moons side-by-side.

27th体育在线365: Crescent Moon below Venus.

28th体育在线365: Crescent Moon above-left of Venus.

31st: Mars very close to Saturn.

Check out TAS’s events calendar at

Ken Kopczynski is president of the Tallahassee Astronomical Society, a local group of amateur astronomers.

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