Heads UP! for July 2019

Fifty years ago, a guy spent lots of precious fuel looking for a parking space in the Sea of Tranquility.  Fifty years from now, I guess there will be a “ParkYourLEM” app for that.  You can see how it looks from here for yourself as the Sun rises over Tranquility Base in the evening of July 7th.  Looking on the 8th is the same sun angle Apollo XI* had.   The best time to see all the Apollo landing sites is the 11th through the 13th in the evening and 21st and 22nd in the morning. I’ll have a map for those dates in a later post.

Summer nights are short nights, and there are many things we can’t see from here.  On the 2nd, a total solar eclipse slashes across the South Pacific and cuts a 125-mile-wide strip of darkness across Chile and Argentina.  The path misses Buenos Aires by 20 miles with the Sun 1 degree above the horizon.  July 16th has a partial lunar eclipse visible from most of the world, except here.  Oh. Except for a light shading at moonrise at Nantucket and eastern Maine.  That same full moon eclipses Saturn, and later in the day, Pluto, for some observers in the Southern Hemisphere, but not during the lunar eclipse.

Here’s the most incredible thing we won’t see – Venus passes behind our Moon on July 31st for much of the USA.  The pair will be five degrees to the lower left of the Sun in the late afternoon our time.  The Moon will be so close to the Sun as to be invisible.  I know.  I tried finding Venus ten degrees above the Sun in midmorning on July 1st. I suceeded by knowing the height of Venus above the horizon and pointing my telescope there.  The Moon was just to Venus’ right.  I couldn’t spot the Moon, even in the telescope.  (I don’t recommend trying this as the Sun is moving in the direction of the Moon and Venus as seen in the sky from our point of view, making this a dangerous observation.)

Oh, the things you can see!  During the 4th of July fireworks point out the two-day-old moon low in the west-northwest. (See chart, below, for 9:15pm Local Daylight Time.)

Star chart from Heavens-above.com for 9:15pm local daylight time on July 4th.

 Mercury, Mars, Pollux and Castor will be hiding a few degrees above the horizon to our Moon’s lower right. Is it possible to see these objects, even with binoculars?  Is it possible to see the Beehive Cluster between the Moon and Mars?  Maybe, and, I doubt it, respectively.  To the upper left, there’s a dynamic scene of Leo pouncing on the Moon.  Jupiter will be easy to sight in the southeastern sector with Saturn just rising to its lower left. Which will be the first stars to come out that night?  Perhaps Arcturus almost overhead, then Vega and Deneb in the east?  That afternoon, we’ll be at aphelion for the year, at 94,513,221 miles away from the Sun, we’ll be just over 3 million miles farther than at perihelion in January.  Mars will be about as far away from us as Mars can get, at 238,700,000 miles.  Mercury is a bit more than half the Sun’s distance from us at 53,600,000.  Mercury and Mars are both near aphelion, Mercury on the 7th and Mars in late August.

For a star chart for the whole month, one of my favorite sites is skymap.com.

The other three inner planets are swallowed up in the Sun’s glare by midmonth.  Mercury passes between the Earth and Sun on the 21st, but not directly in front of the Sun – that Transit of the Sun will happen on the next pass on November 11th.  The SOHO satellite’s C3 camera will show Mercury giving the Sun a wide berth, five degrees to the south of the Sun from the 17th through the 25th.  Mars appears as if it is resisting the Sun’s attempts to make it hard to see, slowly following Mercury into the glare.  Careful observers may get a glimpse of a large crescent Mercury as the planet’s appearance swells to one-quarter of the apparent size of Jupiter.

Mercury at inferior conjunction, with other inner planets in attendance, on July 21st.

Venus had a long run in the morning sky, and like Mars, will crawl past the Sun in our skies.  The brightest planet (from our point of view) will spend two months in the C3’s field of view starting July 16th.  

Now, Jupiter gets up where we can see it, highest by 11:30pm on the 1st and during twilight by the end of the month.  Don’t worry, Jupiter’s features can stand up to viewing in our summer twilight skies.  Watch for Jupiter’s Great Red Spot unraveling.  Will it come undone? 

Saturn rises at sunset as it makes its closest approach on the 9th.  Its shape is obvious with optical aid.  Later at night, high power in steady skies will make the ringed planet even more of a joy to see.   Iapetus is brightest this month, farthest to the west (ahead) of Saturn on the 15th.   Pluto is two degrees southeast of Saturn.  We are also closest to Pluto this month, on the 14th.  But Pluto is 1/4,000,000th as bright as Saturn.

After true darkness descends around 10:30pm local daylight time, the Milky Way is back, arcing across the eastern sky with the center of the galaxy between and just below this month’s Guardians of the Galaxy, Jupiter and Saturn.

The Manhattanhenge solar lineup with the cross streets of Manhattan happens again at sunset on the 12th and 13th.

The International Space Station returns to the morning skies in the first half of the month.  It pulls some all-nighters, visible every 93 minutes, from around the 15th through the 21st.  The ISS sails across the evening sky for the remainder of the month.  

*Half a century ago, we numbered space missions with Roman Numerals.  That led to typesetting errors in newspapers like “Apollo II” or “Apollo X1”.  Sometimes the astronauts used Arabic Numerals on mission patches.

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