April begins with the moon at its new phase ? almost in front of the sun. Because the moon?s orbit is slightly tilted with respect to the plane of the Solar System, we don?t see eclipses at each new moon, only at the times when the orbit crosses the ecliptic. The next lunar eclipse is June 15. April 7, the thin slice of the young moon crosses in front of the Pleiades; then April 9, it grazes the star cluster M35. On the morning of April 17, Saturn and the nearly full moon are within eight degrees of each other. Full phase occurs that evening. April 30, just before sunrise, Venus is seven degrees south of our fading satellite.
Mercury reappears from in front of the sun toward mid-month in the early morning sunrise. The swift planet passes within a degree of Mars April 19. During the final week of April, look for Jupiter, Mars, Mercury and Venus lined up in the morning twilight. Uranus is in there, between Mercury and Venus, visual aid, binoculars or a telescope, is needed to see it.
Venus, in Morning Star configuration, shines brightly during the hour or two before dawn. The morning of April 19 should present a highly photogenic spectacle, with the four bright planets and the moon all in a 20 degree space. Referring to the tilt of the moon?s orbit above, the planets are also slightly tilted with respect to the sun?s ?equator? projected onto the Solar System. Because Earth is a little below that plane, we are seeing the inner planets right now as viewed from below their orbits.
Mars appears in the morning close to the sun near month-end, but it gradually pulls away. Jupiter seems to be swiftly catching up to the Red Planet, and the two are quite close on April 30. Both planets are retrograding ? seemingly moving westward. Remember everything is in motion, and it is us on Earth moving faster than those two planets that makes them appear to move ?backward.?
Jupiter will be a tough observation, even helped by its great apparent brightness. It is too close to the sun until near month-end to be visible. Watch for it with the other three planets as described in Mercury above. British amateur astronomer Damien Peach has created a magnificent movie showing the rotation of Jupiter. Find it at http://www.damianpeach.com/barbados10/20100912whole.wmv.
Saturn is the one naked-eye planet visible during April nights. It rises in the east as the sun sets in the west, crossing the sky all through the night against the stars of Virgo, The Maiden. A recent IMAX movie made from still photos by the Cassini spacecraft shows a stunning fly-through of Saturn and its rings. Type this Tiny URL into your Web browser http://tiny.cc/1xovo to see a great show.
Uranus rises in the east just before dawn, getting higher in the sky with each passing day. Venus and Mercury bracket the blue-green planet during the latter half of the month.
Neptune rises in the east about 5:30 a.m., crossing the sky during the day.
? James Edgar has had an interest in the night sky all his life. He joined the Royal Astronomical Society of Canada in 2000 and quickly became involved in the Society. He is editor?s assistant and a contributor to Observer?s Handbook, production manager of the bi-monthly RASC Journal, and is the Society?s National Secretary.
