April Sky Chart; Northern Hemisphere gazer's guide

April 1: This is about the last morning you will see the waning crescent moon , rising in the east before the sun. If you have an especially clar horizon, you might still see it tomorrow morning, but chances are slim.

April 2: Mars is in conjunction with the sun (in the same direction, as seen from Earth). The ruddy planet has been dawdling along as a poor evening star all year, and it now leaves the evening sky to become a morning star. Don't expect to see it soon in the morning, however; probably not before late July. Even then it will be only a second-magnitude star (not much brighter than the North Star) until quite late in the year.

April 3: Mercury, a poor morning star, is very close to the waning crescent moon this morning, but there is little chance of seeing it. April 5: The moon is at perigee (nearest Earth) today about 24 hours after new moon. The effect of perigee will enhance the normally stronger springtide that comes twice monthly at syzygy (when sun, moon, and earth are in line). High tides will be exceptionally strong today and tonight.

April 7: Venus is in superior conjunction (in line with and beyondm the sun), leaving the morning star to become an evening star. Unlike Mars, however, the much brighter Venus will be easily seen in the evening by late June. However, this will not be a favorable evening elongation for Venus. Though bright, it will be low in the sunset sky and set early through the end of the year.

April 10: You should be able to see the new crescent moon tonight, high in the west early in twilight, but quite slim. If you miss it tonight, look tomorrow, when it will be fatter and higher.

April 16-17: This will be a great night to watch the moon slide past Jupiter and Saturn! After sundown, the three objects will be above the horizon in the east, the waning gibbous moon (three days before full) so bright that the two planets will be the only objects visible near it. When you first see them, Jupiter (clearly brighter than Saturn) will be to the moon's right, Saturn below the moon; but in a very short time the motion of the moon will be apparent, and the arrangement changes as they move up the sky. The moon will pass closest to Jupiter at about 8 p.m. Eastern standard time, closest to Saturn about 1 a.m. EST (on the 17th). By that time, all three objects will be high in the south. The bright star (about as bright as Saturn) below them early in the evening, to their left as they move up the sky, in Spica, in Virgo.

April 17-18: The moon is near Spica, with Jupiter and Saturn to their west (right).

April 20: The moon is at apogee, the position in its orbit where it is most distant from Earth.

April 21-22: The Lyrid meteor shower reaches maximum at about 3 a.m. EST on the 22nd. A reasonably reliable but not particularly productive shower, the Lyrids produce about 15 shower meteors per hour for the careful observer. Look for these not very bright objects from about 1 a.m. on. Don't bother on the mornings before and after the 22nd, however. April 27: Mercury takes its turn at passing the sun in superior conjunction (beyond the sun). Moving from the sun's right to its left, the planet becomes an evening star after passing through a very poor morning elongation. Its position in the evening sky will be much better, however, and you stand a fair chance of seeing it by late May or early June.

May 3-4: The moon is again in perigee, this time within an hour of new moon, raising another perigee springtide tonight and tomorrow. The effect of perigee will be even stronger than in early April, since it occurs so close to the time of the new moon.

All month: Only awhile ago, planets were pretty scarce in the evening sky (for half of February and most of March, there was only Mars, and even it barely made it). This month their cycles of configurations are bringing them in a stampede to the sun's east, and during the month three of them make the transition. Six of the eight planets are morning stars for at least part of April, but six are also evening stars for all or part of the month.

Despite all the shifting around between the morning and the evening sky, however, only two planets, Jupiter and Saturn, are easily visible this month, and, interestingly, both at night and in the morning. The other planets, whether east of the sun (evening stars) or west (morning stars) are above the horizon only in daylight or bright twilight. Jupiter and Saturn are on the star map near Spica, the bright star in Virgo. You can find them very close to each other above the eastern horizon. By morning they are in the west, setting during morning twilight. To find them at either time, just look for the brightest object in the sky. That will be Jupiter (except when the moon is around). The bright starlike object near it is Saturn. The next bright object (about as bright as Saturn) is Spica. The night of April 16-17 will give you an exceptional opportunity to find them near the bright, nearly full, waning moon.