Natural Calendar December 2011

Natural Calendar - December 2011

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!

Note: You can click on the hyperlinks to learn more about some of the featured items. To return to the Calendar, hit the "back" button on your browser, NOT the "back" button on the web page. All charts are available in a "printer friendly" mode, with black stars on a white background. Left clicking on each chart will take you to a printable black and white image. Please note that images on these pages are meant to be displayed at 100%. If your browser zooms into a higher magnification than that, the images may lose quality.

Though we link book references to nationwide sources, we encourage you to support your local book store whenever possible.

Notes and Images From November 2011

The 20 Inch Scope November 12th With Its New Truss Tube Frame. The Mirror is Partially Covered in this Shot.

Some of our best views of deep sky objects have been with our 20-inch Newtonian reflector. In dark skies we've seen the deep red color of the Orion Nebula when using the telescope visually.

The scope also performed well on the planets. We used it during the close Mars opposition of 2003 to get our first ever views of the tiny Martian moons Deimos and Phobos. In this telescope the planet Neptune, though appearing very small, is a perfect robin's-egg-blue.

Unfortunately, the tube of the big scope was made out of a cardboard form used for pouring concrete columns. Although the outside of the tube was covered with fiberglass, the inside was damaged by rain in 2003.

The telescope laid dormant for almost seven years while we pursued other projects. Then we discarded most of the old tube and mounting, and rebuilt the scope as the lightweight truss tube design shown at right. It's much easier to set up and use in this configuration, with no heavy lifting involved. A lightweight black nylon "light shroud" covers the open truss tube when the scope is in use. The scope sits on an driven equatorial platform to allow it to track the stars and planets. We're within a few days of finishing up, and hope to be ready to photograph the planets again soon.

Sky Events for December 2011:

The Winter Solstice for the Northern Hemisphere occurs at 11:30pm Central Standard Time on December 21st. This is the longest night of the year for the Northern Hemisphere, and the official beginning of winter in this hemisphere.

This year's Geminid Meteor Shower peaks in the afternoon hours of December 14th. Because of this it will be best observed on the evenings of December 13th and 14th. Viewing conditions are marginal, with a waning gibbous Moon nearby.

Evening Sky:

A Total Eclipse of the Moon occurs in the early morning hours of December 10th. Unfortunately, the Moon will set for our area while it is entering the penumbra, so the wonderful views available during totality will not be visible.

Look for bright Jupiter at the beginning of the month along the Aries-Pisces border. The great planet is about 40 degrees above the eastern horizon as the evening begins. Binoculars will show the Galilean moons if you hold them steady.

Venus becomes very prominent this month low in the southwest after sunset. About 30 to 40 minutes after sunset is a good time to look for it. At magnitude -3.9, it is the brightest star-like object in the sky.

Mars rises about 11:20pm in Leo at the beginning of the month. The red planet is steadily brightening, and is about magnitude 0.7. Though still small telescopically, it grows from 7.1 seconds of an arc to 8.9 seconds of an arc by the end of the month, allowing some detail to be seen.

Morning Sky:

Saturn rises a little after 3:00am at the beginning of the month, and will be in good position to view in the predawn sky before sunrise. It rises alongside of the bright star Spica in Virgo. Saturn will be the brighter of the two objects. The rings will open up to 15 degrees tilt by the end of the month, the most open view we've had since 2006. Just about any telescope will give a stunning view.

Mercury climbs into the dawn sky this month, reaching greatest elongation on December 23rd. Look for it low in the southeast before sunrise.

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

The Orion Nebula, Messier 42, February 2008, 85mm Apochromatic Refractor and & ST2000XCM CCD Camera, Total Exposure Time 2 Hours. Clicking on the image will take you to a larger higher resolution image.

Constellations: The views below show the sky looking east at 9:30pm CST on December15th. 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.

Look for the bright stars Castor and Pollux in the constellation of Gemini, The Twins. Compare the colors of the bright stars Betelgeuse and Rigel in Orion. Betelgeuse is a red giant and Rigel is a very hot, blue-white supergiant. If you have a telescope, point it to the center of the three "sword" stars below Orion's belt. There you will find the Orion Nebula, M42, one of the most magnificent emission nebulas in the sky. The pink glow of hydrogen alpha light is visible only in very large telescopes and the nebula appears as a small greenish glow in small telescopes. Crouching beneath the feet of Orion, is Lepus, the Hare. Sirius, the brightest star in the sky, shines below Orion. Sirius is in Canis Major, the Great Dog, and for that reason is known as the Dog Star. In the late summer, Sirius rises at the same time as the sun. Because of this, the late summer days are known as the "dog days." The faint constellation Monoceros, the Unicorn, follows Orion over the eastern horizon. Low in the eastern sky below Gemini is Canis Minor, with its bright star Procyon. Procyon means, "before the dog," and refers to the fact that Procyon rises just before the Dog Star, Sirus. Look below Gemini and see if you can spot the faint glow of M44, the "Beehive Cluster." This cluster is located in Cancer, the Crab.

December 15th, 9:30pm, 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 December. 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 Sirius and Procyon in the above scene), 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 three stars in a line in Orion's belt.

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 January 15th at 9:30pm CST, you can stay up till 11:30pm CST on the December 15th and get a preview. The westward motion of the constellations is equivalent to two hours per month. For instance, if you want to see what stars will be on your eastern horizon on March 15th at 9:30pm CST (3 months later), you would need to get up at 3:30am CST in the morning on December 15th (3 months times 2 hours/month = 6 hours).

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:

Upland Chorus Frog

December really marks the beginning of the breeding season for our Tennessee frogs and toads. We have had breeding choruses of Upland Chorus Frogs as early as December 4^th. Breeding even before Wood Frogs, these irrepressible inhabitants of flooded winter fields and other wet areas will call throughout the cold winter months. Listen for their call, which sounds like someone dragging their thumb across the teeth of a plastic comb, on mild wet winter evenings. Listen also for Southern Leopard Frogs. We hear them throughout the fall. Many other Tennessee frogs and toads can also be seen on mild December nights, but most are silent.

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