Last modified: Monday, July 2, 2012
FOR IMMEDIATE RELEASE
July 2, 2012
BLOOMINGTON, Ind. -- At the beginning of July, the first planet to appear in the evening sky will be Mercury, visible near the west-northwestern horizon around 45 minutes after sunset. It will fade rapidly during the first week as it disappears into the glow of twilight.
As twilight fades, Mars and Saturn will appear about a third of the way up the west-southwestern sky. The blue-white star Spica will be just below yellow Saturn and almost as bright. This trio will be joined on July 24 by the crescent moon, making a particularly fine sight in binoculars from shortly after sunset until nearly 11 p.m. local time.
Viewed through a telescope, Saturn's rings will be tilted 13 degrees to our line of sight this month. The planet's largest moon, Titan, will be south of it on July 7 and 23, and north of it on July 15 and 31.
Mars will be a disappointing sight in a telescope during July, but the red-orange planet will move quickly toward Saturn and Spica as the month passes. In mid-August, Mars will appear to pass between Saturn and Spica, an exceptionally tight grouping.
As the month begins, Venus and Jupiter will be less than 5 degrees apart low in the east-northeast an hour before sunrise. Venus will be more than 10 times brighter than higher Jupiter. Directly above Jupiter will be the Pleiades star cluster. Close below Venus will be the bright orange star Aldebaran, which will be overwhelmed by the dazzling white planet. Venus will pass less than 1 degree north (right) of Aldebaran on July 10. By month's end, Venus and Jupiter will be much higher and farther apart.
The southern branch of the Delta Aquarid meteor shower will peak before dawn July 30. After the moon sets around 3 a.m. local daylight saving time, the dark sky will offer ideal viewing conditions for an hour before morning twilight begins. As many as 20 meteors per hour may be visible. Meteors will appear several nights before and after the peak as well. The long bright streaks will seem to come from a point in the constellation Aquarius in the southern sky during the hours just before morning twilight.
On July 4, Earth will reach its greatest distance from the sun for the year, called aphelion. Those sweltering in summer heat in the Northern Hemisphere may find it hard to believe that they are about 3 percent farther from the sun than they were in January. Those experiencing winter in the Southern Hemisphere will be easier to convince. The difference is caused by the tilt of Earth's axis. The part of the planet tilted toward the sun is much warmer than the part tilted away, because more sunlight reaches the ground instead of being absorbed by the atmosphere.
The moon will be full on July 3, at third quarter on July 11, new on July 19 and at first quarter on July 26.