The Sky This Week for July 5 to July 10
Jupiter shines bright like a firework, Saturn dazzles, and Mars enters its autumn season.
By Richard Talcott
Tuesday, July 5
• Today marks the first full day of autumn in Mars’ northern hemisphere. The Red Planet’s autumnal equinox arrived around noon EDT yesterday, so the Sun is setting over the north pole for the first time in half a martian year (nearly one of Earth’s years). The timing is great for earthbound observers because Mars remains a stunning sight this week. It shines at magnitude –1.3 and dominates the sky toward the south-southwest as darkness falls. When viewed through a telescope, Mars’ orange-red disk spans 16″. The planet’s north polar cap should appear near its minimum extent now that summer is finally over. Look for a patch of white — the permanent cap of water ice — near Mars’ northern limb.
Wednesday, July 6
• Neptune rises shortly before 11:30 p.m. local daylight time this week and climbs some 40° above the southern horizon by the start of morning twilight. The magnitude 7.9 planet lies in Aquarius, some 0.5° southeast of 4th-magnitude Lambda (l) Aquarii. You’ll need binoculars to spy Neptune and a telescope to see its blue-gray disk, which spans 2.3″.
• Mercury passes behind the Sun from Earth’s perspective at 11 p.m. EDT. This means the innermost planet lies on the opposite side of the Sun from Earth and remains hidden in our star’s glare. It will return to view in the evening sky by the end of the month.
Thursday, July 7
• Today marks the peak of Pluto’s 2016 appearance. The distant world reaches opposition, which means it lies opposite the Sun in our sky and remains visible all night. It glows dimly at magnitude 14.1, however, so you’ll need an 8-inch or larger telescope with good optics to spot it visually. Pluto currently lies in northeastern Sagittarius, some 0.3° west-southwest of the 3rd-magnitude star Pi (p) Sagittarii. See “The quest for distant Pluto” in the July Astronomy for complete details on finding this world.
Friday, July 8
• The Moon passes 1° south of Jupiter tomorrow morning, unfortunately after the two objects have dipped below the western horizon. But the view this evening is nearly as nice. The waxing crescent Moon stands 3° to 5° (depending on where in North America you live) to the planet’s lower right. Tomorrow evening, a slightly fatter crescent Moon will appear about twice as far to Jupiter’s upper left.
Saturday, July 9
• The Big Dipper’s familiar shape lies high in the northwest as darkness falls these July evenings. One of the summer sky’s finest binocular double stars marks the bend of the Dipper’s handle. Mizar shines at 2nd magnitude, some six times brighter than its 4th-magnitude companion, Alcor. Even though these two are not physically related, they make a fine sight through binoculars. (People with good eyesight often can split the pair without optical aid.) A small telescope reveals Mizar itself as double — and these components do orbit each other.
Sunday, July 10
• This should be a good night to hunt down asteroid 7 Iris through a small telescope. The 10th-magnitude object lies nearly due south and at its highest position in the sky as darkness falls. Even better, there’s a reasonably bright guide star to point you in the right direction. This evening, look for Iris 0.5° due south of the magnitude 5.0 star Lambda (l) Libr
Source
Witches Of The Craft® 