The purpose of this feature is to give scout leaders, educators and naturalists an idea of some of the natural events coming up each month.  We will try to cover a variety of natural events ranging from sky events to calling periods of amphibians, bird and mammal watching tips,  prominent wildflowers and anything else that comes to mind.  We will also note prominent constellations appearing over the eastern horizon at mid-evening each month for our area for those who would like to learn the constellations.  If you have suggestions for other types of natural information you would like to see added to this calendar, let us know!

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Notes and Images From May 2015

A large high pressure system moved over the state in the first week in May, and it allowed us to set up the 20 inch Newtonian telescope for planetary imaging.

It was a beautiful afternoon when I was putting the scope together on May 2nd.  A Prairie Warbler flew up to the top of the cedar just north of the observatory and sang.  I spotted a small movement along the wall of the observatory and found it to be a female Tan Jumping Spider, Platycryptus undatus.  This was the first of this species that we've seen at our farm. This one was hunting, and it soon caught a small plant bug (genus Dichrooscytus) that I had photographed earlier.  I noticed many ants making their way past the spider with no apparent fear, and it did not seem to be interested in them as prey. 

The spider seemed fairly large for this early in the season, and on checking I found that this species sometimes overwinters.  As many as fifty of these spiders have been observed hibernating en masse beneath the bark of trees like the Shagbark Hickory.  The scaly bark of the Shagbark Hickory also provides protection from the winter cold for some treefrogs and bats.

I planned on imaging both Jupiter and Saturn.  These two gas giants make up over ninety percent of all of the planetary mass in the solar system.  My first target was Saturn, which would not reach its highest point in the sky until the early morning hours of the following day.  At the present time Saturn doesn't climb very high in the southern sky, and it's important to image it at its maximum altitude.

I set the alarm clock for 1:00am, and when I made my way out to the telescope I was surprised to find the atmosphere fairly steady.  A nice chorus of frogs drifted up from the pond. 

In the above image, the darkest feature in the ring system is Cassini's Division, discovered by Giovanni Cassini in 1675.  You can see the globe of Saturn through the division.  The translucent innermost Ring C was discovered in 1850 by William C. Bond.  It is also known as the "crepe" ring, after the translucent black silk that was used in mourning clothes in the 19th century.  

The atmosphere was pretty unsteady for the next few nights, but on May 8th conditions improved.  This time I imaged Jupiter.  I started imaging in the twilight sky, and after a short time the seeing deteriorated.  But I was able to get enough data to make the image at right.

Sometimes I think about Galileo when I look at Jupiter and Saturn.  The discovery of the four brightest moons of Jupiter was one of Galileo's biggest triumphs.  Saturn frustrated him.  When he first observed Saturn through his telescope the rings appeared partially open, similar to the image of Saturn above.  His telescope was not good enough to allow him to see the rings completely encircling the planet.  Through his telescope Saturn looked like a large globe with a smaller globe on each side.  As Saturn orbits the Sun, the rings appear to slowly open and close in a 29 year cycle.  When Galileo returned to Saturn a few years later, the rings were "edge on" and invisible.  His two smaller globes had disappeared!  In a letter he wrote;

"What can be said about so strange a metamorphosis?  Are perhaps the two smaller stars consumed, like the spots on the Sun?  Have they suddenly vanished and fled?  Or has Saturn devoured his own children?...I cannot resolve what to say in a chance so strange, so new, and so unexpected; the shortness of time, the unexampled occurrence, the weakness of my intellect and the terror of being mistaken, have greatly confounded me."

He never solved the puzzle.  His telescope simply did not have enough resolution to make out the rings in all their glory.  Almost any small telescope you can buy today will give a view of Saturn that would have answered Galileo's questions.  I think of him sometimes when I'm looking at the rings.  Just for a moment I imagine him standing beside me.  Here they are, I say, look here.

Sky Events for June 2015:

The Sun reaches the June solstice at 11:38pm CDT on June 21st.  This marks the beginning of summer in the Northern Hemisphere.

Evening Sky: 

Venus reaches greatest elongation from the Sun on June 6th.  Look for it above the western horizon starting about 30 minutes after sunset.

Jupiter moves through Cancer into Leo this month.  Look for it in the early evening in the western sky, above and to the left of Venus as the month begins.

Jupiter and Venus put on a spectacular show this month.  The apparent distance between the two planets, both bright beacons in the western sky, diminishes as the month goes on, and the two will form a striking pair in the twilight sky towards the end of June. 

They are closest on June 30th, when the angular separation between the two is less than a third of a degree.  This amount of separation should allow both planets to be viewed in the same eyepiece field of view.  Though Jupiter is much larger than Venus, it's much farther away, so the planets will appear about the same size.  Venus will show a crescent phase.  It should be quite a visual treat, and quite beautiful in binoculars.  Try to get binocular or telescopic views just as soon as you can spot Venus in the twilight sky.  A brighter background sky really helps, particularly with Venus.

Saturn rises about a little after 6:55pm CDT at the beginning of the month in Libra.  Look for it low in the southeast.  Saturn's rings have opened up to more than 24 degrees tilt, giving a wonderful view of the ring system through just about any aperture telescope.  Saturn transits around 11:03pm CDT at mid-month, and you will get your best telescopic view around that time. 

Morning Sky: 

Look for Mercury low in the morning twilight at month's end, about 6 degrees above the eastern horizon.  Begin looking about 45 minutes before sunrise.

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.

In June the treefrogs really hit their stride.  Listen for Cope's Gray Treefrogs,  Gray Treefrogs, Bird-Voiced Treefrogs, Green Treefrogs and Barking Treefrogs.  Eastern Cricket Frogs and Southern Cricket Frogs call a lot during June, and the calls of Bullfrogs, Green Frogs and Fowler's Toads fill the night air.  After heavy rains listen for the high, insect-like call of the Eastern Narrowmouth Toad and the strange-sounding Eastern Spadefoot.  

Recommended:  The Frogs and Toads of North America, Lang Elliott, Houghton Mifflin Co.

Birds:

Now is a good time to get to know the breeding birds of Tennessee.  It's fun to take a trip to the Great Smoky Mountains National Park in June and hike a high altitude trail, like the Alum Cave Bluff trail.  By doing so you can encounter birds that breed in Tennessee at these higher elevations, like Black-throated Blue Warblers, Canada Warblers, Chestnut-sided Warblers and Blackburnian Warblers. 

Recommended:

The Sibley Guide to Birds, David Allen Sibley