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July 2015 Urban Observing July 6, 2015

Posted by aquillam in Astronomy, MichiganAstro, Urban Observing.
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Special Events

Aphelion

Aphelion (ap-HE-lee-on) occurs on July 6 at 19:41 UT (3:41 EDT). That’s the point in the orbit where a Earth is farthest from the Sun.

Blue Moon

The first full moon of July occurs on July 2 at 2:20 UT (that’s 11:20 on July 1 here in Ann Arbor). The second is on July 31 at 10:43 UT (or 6:43 AM EDT). The popular definition of “blue moon” is the second full moon in a month, and that makes the July 31 moon a blue moon. Another (older) definition is the third of four full moons in a season. Since summer started on June 21, the full moons of July are actually the first and second full moons of summer, and there are only 3 full moons this season.

Meteor Showers

The Delta Aquariids bring to an end the quietest months for meteor watchers. Unfortunatly, they should peak on the 28 – 29, just before the second full moon of the month. Start looking for them in the pre dawn skies about a week before that, after the Moon has set. That means looking for them between 2 – 4 AM local time from July 21 – 26. For the peak and a few days around it, your bet bet will be around 3 -5 to avoid as much moonlight as possible and the morning twilight. After the peak, the waining moon is impossible to avoid, and the Moon passes through Aquarius on August 2. The radiant will be highest around 3 – 4 AM both weeks.

Location of the Delta Aqu. radiant on July 29 at 3:42 AM in Ann Arbor.

Location of the Delta Aqu. radiant on July 29 at 3:42 AM in Ann Arbor.

Planets

Mercury

is a morning planet at the start of the month. It will be difficult to spot, but if you’re up for a challenge and have a pair of binoculars, look for Mercury, Mars, and an old Moon half an hour before sunrise on July 14. It disappears into the glare of the Sun not long after, but look for it’s return to the evening skies in August!

Mercury, Mars and the Moon align on July 14, about 20 minutes before sunrise.

Mercury, Mars and the Moon align on July 14, about 20 minutes before sunrise.

Venus

is spectacular in the west all month. A waning crescent, it is getting ever closer to us, which means bigger and brighter too. By the end of the month, you should be able to tell it’s a crescent with just a small pair of binoculars. Here are a couple images to help you compare size (both simulate a 15″ field of view.)

The appearance of Venus on July 31 in a telescope with a 15 arcminute field of view (approx.)

The appearance of Venus on July 31 in a telescope with a 15 arcminute field of view (approx.)

The appearance of Venus on July 1 in a telescope with a 15 arcminute field of view (approx)

The appearance of Venus on July 1 in a telescope with a 15 arcminute field of view (approx)

Mars

emerges from the glare of the Sun this month. It is less than half a degree from Mercury on the 16th! Unfortunately for most of us, you’ll have to be up before the Sun to see it.

Conjunction of Mercury and Mars on July 16 about 20 minutes before sunrise.

Conjunction of Mercury and Mars on July 16 about 20 minutes before sunrise.

Jupiter

After the conjunction with Venus on June 30, Jupiter works his way slowly to the east, winding up in a conjunction with Mercury and Regulus around August 6. Look for Venus, Jupiter and a young moon together on July 18.

Venus, Jupiter, the Moon, and the star Regulus on July 18 at 9:30 PM (about half an hour after sunset)

Venus, Jupiter, the Moon, and the star Regulus on July 18 at 9:30 PM (about half an hour after sunset)

Saturn

It’s a great month for observing Saturn. It is high in the south at 10 PM, but getting farther from us all the time. The quarter moon passes by it on July 25 – 26.

Saturn and the Moon on July 25 at 10 PM.

Saturn and the Moon on July 25 at 10 PM.

Deep sky

July snuck up on me, so I don’t have any deep sky stuff prepared. Maybe I’ll get a few things posted as the month progresses. In the meantime, I’ll just throw a couple things out there.  ‘Tis the season for Albireo, a maize & blue binary in Cygnus. Not far from M13, a globular cluster in Hercules, which is a naked eye object in dark skies. Compact planetary nebula M57 sits between the two stars at the bottom of the harp in Lyra. It’s smaller size helps it stand out against a pretty bright sky in a small ‘scope.

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