Natural Calendar March 2012

Natural Calendar - March 2012

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 February 2012

Eastern Redcedars bordering our Pond - February 28th

One of our daily routines is an evening trek down to our barn to take care of our animals. Our path takes us through our field, and it's amazing what we encounter along that brief walk. We've seen and heard American Woodcock courtship flights, heard a host of amphibian choruses and some grand summer insect orchestras. We've had some really pretty views of snakes like the Rough Green Snake. We regularly see wonderful starscapes. Our path keeps us in touch with what's going on at our farm.

When we walked to our barn on the evening of February 23rd it was partly cloudy, but there were no clouds overhead. We were perplexed by a mist that kept showing up in our headlamps. It wasn't water, and it wasn't smoke. On the way back, Andrea stopped and gently moved one of the Eastern Redcedars that line the path. Instantly, she was enveloped in a cloud of cedar pollen that billowed all around her in the light of the headlamps. Eastern Redcedars are dioecious (literally "two houses") meaning the male and female reproductive structures are carried on separate trees.

Eastern Redcedar Male Cones, Nikon D40x, March 25, 2005

In late winter and early spring the yellowish male cones, shown at left, crowd the branches of the larger male cedars. We had been walking in a cloud of pollen from our many trees.

The female reproductive structure is also a cone, but relatively inconspicuous until later in the spring. Then the powder blue seed cones are easy to see on the female cedars.

The blue seed cones are a favorite for many types of wildlife. Cedar Waxwings regularly eat the cones and take their name from this tree. Many other songbirds eat the fleshy cones, and the cedar seeds are often distributed along fencerows in the bird's droppings.

Eastern Redcedar Female Seed Cones, Nikon D40X, May 16th, 2005

Many birds nest in cedars, and owls such as the Eastern Screech-Owl often roost in the dense foliage. This tree is the host plant for the beautiful Olive Hairstreak, a butterfly. Deer browse the leaves, and small mammals make use of the cover it provides.

This is a pioneer species, and it tolerates virtually all soil conditions except those that are quite swampy. Cedars are often among the first new species colonizing a habitat. In his classic A Natural History of Trees, Donald Culross Peattie says, “No stone-walled hilltop too bleak, no abandoned field too thin of soil but that the dark and resolute figure of the redcedar may take its stand there, enduring, with luck, perhaps three centuries.” To us, the stands of Eastern Redcedar that inhabit the rolling farmland of middle Tennessee are an essential part of what makes it feel like home.

The 20 inch Newtonian Sitting on the Equatorial Platform

I was being something of an optimist when I set up our 20 inch reflecting telescope on February 6th. The sky was completely overcast. But the weather predictions called for the sky to clear around 5:00pm, and the sky was supposed to remain clear till morning.

We had pretty much finished up our rebuilding and tweaking of the big reflector, and, with a lot of help and expertise from Andrea's mom, finished the devilishly complex (to me) black nylon "light shroud" that encloses the truss tubes and shields the optical train from stray light. Also, after several attempts, we had designed and installed a slow motion control on the altitude axis of the scope that greatly simplified planetary photography.

Planetary imaging takes very steady atmospheric conditions to be successful, and so far we had been frustrated by the weather. But the temperature was not supposed to fall much during this evening and the jet stream was not going to be directly overhead. This all boded well for good imaging conditions.

Sure enough, the clouds cleared in the late afternoon. As the sky darkened, I heard the raspy "peent!" of an American Woodcock coming from our field. We'd had woodcocks in the fields around us in years past but not from our field. It seemed like a good omen. A big rising full Moon insured that the courtship flights would continue into the night.

Mars, February 7th, 2:02am, 20 inch Newtonian Reflector and Flea 3 Video Camera. Bright clouds over Elysium Mons are just left of center.

As the woodcocks did their aerobatic displays, I tweaked the alignment of the optics on the scope and started the mirror cooling fan. Now we had to wait for our first target, Mars, to gain enough altitude above the horizon to allow steady imaging.

We started imaging around 11:30pm. With planetary imaging we use a monochrome video camera to take videos lasting a couple of minutes or so through red, green and blue filters. The sharpest images from each of the color-filtered videos are selected by computer software, and the filtered videos are combined to make a color image. The red and green filtered videos show mainly ground features, while the blue-filtered video shows mainly cloud features.

From the first video we could see that the atmospheric conditions were pretty good for imaging. We were able, in the blue-filtered video, to see the clouds over Olympus Mons, the largest mountain in the solar system. The best conditions occurred around 2:00am. Olympus Mons was no longer visible, but I could still see a bright spot over Elysium Mons, another extinct volcano, and the north polar cap (seen at the bottom of the above image) was very bright. Haze over the south pole, known as the south polar hood, was also visible. Bluish clouds were visible over the very dark surface feature Syrtis Major, which had just rotated into view. And there was abundant surface detail! What a night!

Saturn, February 7th, 2:30am, 20 inch Newtonian Reflector and Flea 3 Video Camera

Now it was time for Saturn. The great planet was still a little low around 2:30am, but while the atmosphere was steady I wanted to try and get some images.

The atmosphere continued to remain steady. While the imaged blurred at times, there were moments when details like the dark Cassini's division stood out very sharply.

The night world seems peaceful in the early morning hours. Two Great Horned Owls called softly back and forth from the tree line that borders our field. Upland Chorus Frogs called very slowly from our pond. A Birmingham-bound freight train passed. A chorus of coyotes began calling, their high calls and yipping notes coming from across the tracks, though they seemed very close. The woodcocks continued to call, and every now and then I'd hear the soft twittering notes that they make as they dive and swoop back to the ground after their long spiraling climb.

I continued to video Saturn till around 5:00am. It was then about 27 degrees Fahrenheit, and I was starting to feel a little tired and cold. Frost covered the scope and the keyboard of my computer. I turned off the drive of the scope, lugged the computer hardware back inside, and then fell into bed.

Sky Events for March 2012:

The Vernal Equinox, marking the beginning of Spring in the Northern Hemisphere, occurs at 12:14am CDT on the morning of March 20th.

Evening Sky:

There's a lot going on with the Moon and planets in March. In the western sky after sunset Jupiter, Venus and Mercury are constantly changing positions relative to each other. At the beginning of the month, in one evening, you can see all of the namesakes* for the days of the week; the Sun, the Moon, Mars, Mercury, Jupiter, Venus and Saturn.

Look for Jupiter about 45 degrees above the west southwest horizon at dusk at the beginning of the month. It will get lower in the west each day as the month progresses.

Look for bright Venus about 11 degrees below Jupiter in the western sky at dusk. Venus will be much the brighter of the two planets. Venus and Jupiter will draw as close as 3 degrees between March 12th and March 14th. As Jupiter sinks ever closer to the western horizon each day, Venus will set later each day, reaching greatest elongation from the Sun on March 26th.

Mercury will be quite a bit below Jupiter and Venus in the western sky at the beginning of the month, so you will need a flat western horizon to glimpse it. The fast moving planet reaches greatest elongation from the Sun on March 4th. A good time to start looking for Mercury is about 30 minutes after sunset. Binoculars will make Mercury easier to spot, though to avoid damaging your eyes you should wait till after sunset to use them.

Mars rises about 7:43pm CST at the beginning of the month in Leo. Its bright orange-red color, like a glowing coal, make it easy to spot in the eastern sky. It comes to opposition with the Sun on March 3rd, and is closest to the Earth on March 5th. Mars is 63 million miles from the Earth on this date. Due to the elliptical shape of Mar's orbit, the closest approach to Earth varies from one opposition to the next. This year's closest approach of 63 million miles is the most distant approach since 1995. Compare this to the record close approach in 2003 of 34.6 million miles. Still, the red planet always has some fascinating details to record around opposition. For telescopic views, wait until the planet has climbed high in the sky, preferably when it's due south. To see which side is visible, I recommend the Mars Profiler at the Sky and Telescope web site.

Saturn rises around 9:20pm CST on March 1st in Virgo. Best views through the telescope occur when it is due south in the early morning hours. Saturn is stunning in just about any size telescope. See if you can make out Cassini's division in the rings, which appears like a thin black division in the rings. Those using larger telescopes can try for the faint "Crepe" ring, the translucent innermost ring of the ring system, or Encke's division, a faint division in the outermost ring.

Finally, look for a very thin crescent Moon about 30 minutes after sunset on March 23rd. Binoculars should help spot the slender crescent about 8 to 10 degrees above the western horizon.

*While the derivations of Sunday, Monday, and Saturday are pretty obvious, the other days of the week are named after the Norse counterparts of the Roman gods. The Norse equivalent of Mars was Tiw, hence Tuesday. Mercury was Woden, hence Wednesday. Jupiter was Thor (Thursday) and Venus, Frig (Friday).

Constellations: The views below show the sky looking east at 9:30pm CDT on March 15^th. The first view shows the sky with the constellation outlines and names depicted. Star and planet names are in green. Constellation names are in blue. The second view shows the same scene without labels. Stealing the show is the bright planet Mars, shining brightly in Leo. Hidden by the tree line is the rising Saturn. The bright star Arcturus, in Bootes, the Herdsman, makes its appearance this month in the early evening sky, a sure sign that Spring is here. In the southeast, Virgo clears the horizon this month along with Corvus, the Crow. Saturn shines brightly in Virgo. The area of sky encompassing Leo, Virgo and Como Berenices marks the heart of the great Virgo cluster of galaxies.

March 15th, 9:30pm CDT, Looking East

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 March. 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 (Like Arcturus and Denebola in the above scene looking east), 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 of Corvus the Crow.

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. The westward motion of the constellations is equivalent to two hours per month.

Recommended:

Sky & Telescope's Pocket Star Atlas is beautiful, compact star atlas. It is destined to become a classic, and is a joy to use at the telescope.

A good book to learn the constellations is Patterns in the Sky, by Hewitt-White. You may also want to check out at H. A. Rey's classic, The Stars, A New Way to See Them.

For skywatching tips, an inexpensive good guide is Secrets of Stargazing, by Becky Ramotowski.

A good general reference book on astronomy is the Peterson Field Guide, A Field Guide to the Stars and Planets, by Pasachoff. The book retails for around $14.00.

Starry Night has several software programs for learning the night sky. Visit the Starry Night web site at www.starrynight.com for details.

Amphibians:

Southern Leopard Frog

The mild winter has resulted ideal breeding conditions for many species. Upland Chorus Frogs, Southern Leopard Frogs, and Spring Peepers are going strong. American Toads should be calling soon, if they are not already calling where you are. In West Tennessee, Crawfish Frogs continue to give their loud snoring calls early in the month. At higher elevations, listen for Mountain Chorus Frogs. Towards the end of the month listen for Pickerel Frogs doing their "yeeooow" call. Remember that on mild nights you may find frogs and toads out foraging that you do not hear until later in the season. On warm days listen for early treefrogs, like Cope's Gray Treefrog, and for early Northern Cricket Frogs. The Northern Cricket Frogs at our pond often call just before a train passes by our field, possibly stimulated by the vibrations.

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