The Sky This Week 9-16 May 2003
The Moon waxes in the evening skies this week, capping the week with a spectacular total eclipse on the night of May 15th ñ 16th. The Full Planting Moon occurs on the 15th at 11:36 pm Eastern Daylight Time. At this time Luna will be traversing the shadow of the Earth near the mid-point of the eclipse. Look for the Moon near the bright star Regulus on the evening of the 9th. On the 13th she stands less than 5 degrees north of the blue-tinted star Spica.
The total lunar eclipse of May 15th is the first of two such events we’ll see this year. The last one we saw from the Washington area occurred on January 21st, 2000, and we’ll have a ringside seat here on the east coast for this event. The Moon rises just before 8:00 pm on the 15th, and encounters the faint penumbral shadow of the Earth at 9:05. Most folks won’t notice anything unusual until around 9:45 pm, when the lower left edge of Luna’s disc will start to take on a slate-grey cast. At 10:03 the edge of the Moon enters the Earth’s umbral shadow, and for the next 70 minutes moves deeper into the gloom. The total phase begins at 11:13 pm, with mid-eclipse occurring at 11:40. The total phase ends at 12:06 am on the 16th, and Luna exits the umbra at 1:17. The final contact with the penumbra occurs at 2:14 am, when the eclipse officially ends. Since sunlight diffuses through the Earth’s atmosphere before it reaches the Moon, lunar eclipses tend to take on a rusty orange or reddish hue. Exactly how bright or dark the eclipsed disc will be is still anybody’s guess, but since this eclipse transits close to the northern edge of Earth’s shadow I suspect it will be fairly bright. Unlike solar eclipses, lunar eclipses are perfectly safe to watch, so hope for clear skies on the 15th and enjoy watching celestial mechanics in action.
Watching the eclipse from the wings are Jupiter and Saturn which, after the departure of Mercury last week, are once again the only planets visible in the evening sky. Saturn is now making a rapid exit from the sky, and sets about an hour after the end of evening twilight. If you want to catch a last glimpse of him for the year, now is the time to do it. The ringed planet becomes visible in the evening twilight by 8:30, but he’s only 25 degrees above the horizon. By the end of the week he sets at around 10:45.
Jupiter pops into view in the twilight almost immediately after sunset. The giant planet may be found high in the southwest as dusk deepens, but by 10:30 he’s within 35 degrees of the horizon. If you want to train the telescope on his striped cloud belts, mysterious Red Spot, and scuttling moons, you’re better off to do so in the earlier evening hours before he slips behind too much of our restless atmosphere.
Mars now rises about 10 minutes after Jupiter sets. The red planet is wending his way through the middle of Capricornus, the Sea-Goat, and in the pre-dawn hours of the 14th lies about 2 degrees south of the telescopic planet Neptune. Two mornings later he’s about 1? degrees south of the 4th magnitude star Theta Capricorni. He’s becoming steadily brighter, but he’s still over two magnitudes fainter than he will be at this summer’s extremely close opposition.
