Our image for July was started on the evening of June 29th and completed in the morning hours of July 1st.  We have been looking for some time for an opportunity to image a trans-Neptunian dwarf planet.  These small residents of the Kuiper Belt are quite distant.  Pluto is the best known of these objects.  Since they look just like faint stars in any earthbound image, I was hoping to catch one passing close to a fairly bright galaxy, just to make a more interesting image.

I checked on a few of the brighter ones on June 27th and was amazed to find that one of them, the dwarf planet 136472 Makemake, was in fact passing close to the galaxy NGC 4725 in Coma Berenices.  This little dwarf planet is only about 890 miles in diameter, less than half the size of our Moon.  It is now over 52 astronomical units (one astronomical unit is the distance from Earth to the Sun, or about 93,000,000 miles) from the Earth.  For comparison, Pluto is now about 32 astronomical units from Earth. 

Sky Events for July 2016:

Evening Sky:  

Jupiter is in Leo this month, and 20 minutes after sunset is only 19 degrees above the western horizon.  With binoculars, you may be able to pick it out of the twilight glow, and if you look down and to the right of Jupiter, you may be able to pick out Mercury and Venus as well.  Venus is only about 4 degrees above the western horizon, so binoculars will probably be necessary to see it.  In between Jupiter and Venus, look for Mercury, which is about 8 degrees above the horizon.  It should be fun to watch these planets move in relation to each other this month. 

Mars is in Libra as the month begins.  Look for it about 30 degrees above the southern horizon at dusk.  Mars will begin the month around 13 seconds of an arc in diameter, so it's still possible to get a view of some of the surface details.

Saturn is highest above the horizon about dusk, so if you're planning on viewing it with a telescope you'll want to view it as soon as it becomes visible in the southern sky.

All times noted in the Sky Events are for Franklin, Tennessee and are in Central Daylight Time.  These times should be pretty close anywhere in the mid-state area.

Constellations: The views below show the sky looking east at 10:00pm CDT on August 15th.  The first view shows the sky with the constellations outlined and names depicted.  Star and planet names are in green.  Constellation names are in blue.  The second view shows the same scene without labels.  New constellations this month are Pegasus, the Flying Horse, Andromeda, Princess Andromeda, Triangulum, the Triangle, Pisces, the Fishes, and Aquarius, the Water Bearer.

In Pegasus, the reddish star Enif marks the nose of the flying horse.  Just above Enif is the globular cluster Messier 15, a nice ball of stars about 33,600 light-years away.  The cluster was discovered by Jean Dominique Maraldi on September 7th, 1746.  Maraldi was searching for De Chéseaux' Comet at the time.

High overhead, in Hercules, another globular cluster is at its best this month.  Messier 13 can sometimes be picked out with the naked eye on a dark moonless night.  It is about 25,000 light-years distant.

In a small telescope it will appear like a little cotton ball of faint light.  With increasing aperture, you'll be able to spot some of the faint stars around the periphery of the cluster.  Be sure to use averted vision, looking to one side of the cluster, to allow the cluster's light to fall on the light-sensitive rod cells of your eye.

On Learning the Constellations: We advise learning a few constellations each month, and then following them through the seasons.  Once you associate a particular constellation coming over the eastern horizon at a certain time of year, you may start thinking about it like an old friend, looking forward to its arrival each season.  The stars in the evening scene above, for instance, will always be in the same place relative to the horizon at the same time and date each August.  Of course, the planets do move slowly through the constellations, but with practice you will learn to identify them from their appearance.  In particular, learn the brightest stars for they will guide you to the fainter stars.  Once you can locate the more prominent constellations, you can "branch out" to other constellations around them.  It may take you a little while to get a sense of scale, to translate what you see on the computer screen or what you see on the page of a book to what you see in the sky.  Look for patterns, like the stars that make up the "Square of Pegasus."

The earth's rotation causes the constellations to appear to move across the sky just as the Sun and the Moon appear to do.  If you go outside earlier than the time shown on the charts, the constellations will be lower to the eastern horizon.  If you observe later, they will have climbed higher. 

As each season progresses, the earth's motion around the Sun causes the constellations to appear a little farther towards the west each night for any given time of night.  If you want to see where the constellations in the above figures will be on September 15th at 10:00pm CDT, you can stay up till midnight on August 15th and get a preview.  The westward motion of the constellations is equivalent to two hours per month. 

Another great app is the Photographer's Ephemeris.  Great for finding sunrise, moonrise, sunset and moonset times and the precise place on the horizon that the event will occur.  Invaluable not only for planning photographs, but also nice to plan an outing to watch the full moon rise.  Available for both androids and iOS.