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 January 2016
January was bookmarked by two images of the night sky, one begun on January 1st, and the other on January 31st. Both explore the rich winter sky looking south, with its bright stars sprinkled around like diamonds. Orion the hunter strides across the southern sky, accompanied by his two dogs, Canis Major and Canis Minor.
It is to these constellations that we pointed our telescope. The nights were very clear and cold. Our field was silent, with just the occasional call of an owl to break the stillness. As the telescope went through its imaging paces, I watched Jupiter rise each night, its normal cream-colored disc reddened by the atmosphere as it cleared our eastern tree line. In Canis Major, about a fist's width to the left of brilliant blue-white Sirius, is an area of nebulosity sometimes called Thor's Helmet.
In January's Natural Calendar we looked at a supernova remnant, the Crab Nebula. Thor's Helmet is a kind of prequel to that story, a nebula surrounding a star that will probably explode as a supernova. The nebula is located in the heart of the winter Milky Way, and dust and gas are visible throughout the image. Just above the center of the image is the star that created the nebula, the Wolf-Rayet star WR7. This star is about 16 times more massive than our Sun, and 280,000 times brighter! The intense radiation from this brilliant star is responsible for the glowing nebula that surrounds it. When WR7 ends its life as a supernova, it will contract to either a neutron star or a black hole, depending on how much mass it retains after the explosion.
is about 12 thousand light-years distant, and about 30 light-years in
Orion stands above Canis Major this time of year in our southern sky. Near the three prominent stars that make up Orion's belt are three fainter stars that mark his sword. The center somewhat misty sword "star" is in fact the Orion Nebula, Messier 42. The nebula is too large to fit within the imaging field of view of our 12.5 inch telescope, so the image at right is just part of the nebula. You can compare this view with the wide-field image below to get a sense of perspective.
The Orion Nebula is about 1500 light-years distant, and the whole nebula spans about 24 light-years in diameter. Based on that estimate of size, the field of view at right covers about 8 light-years on the diagonal.
Immense clouds of hydrogen and oxygen span the image, looking like straggling storm clouds on a cold winter day. But these clouds stretch for light-years!
Within the nebula stars are in the process of forming. The whole region is thought to be a stellar nursery. The Hubble Telescope has revealed protoplanetary disks forming around some of the young stars.
Like most deep sky objects, the Orion Nebula is best seen on very clear, moonless nights, as high above the horizon as you can catch it. Just about any telescope, or even a pair of binoculars, will give a pleasing view. Visually in small instruments the nebula appears grayish-green. This green hue comes from doubly ionized oxygen. Large telescopes will show some of the deep red color from hydrogen alpha radiation, though it is nowhere near as obvious as in the image. Deep wide field images of this area show that the Orion nebula is part of a much larger complex of nebulosity that extends throughout the constellation.
Sky Events for February 2016:
Jupiter rises about 8:18pm in Leo at the beginning of the month. To get good telescopic views, wait until it is high in the sky. The great planet transits around 2:36am.
Morning Sky:Mars is in Virgo as the month begins, rising about 12:35am. The planet is slowly increasing in apparent size, but is still fairly small in the eyepiece. It's about 6.9 arc-seconds in diameter at the beginning of the month. It's brightening now, and the red color is easily visible in binoculars.
Saturnis climbing higher in the southeast before sunrise at the beginning of the month, rising about 2:52am. The tilt of the rings has now opened to a spectacular 26 degrees. Your best views will be just before sunrise.
Look for Venus low in the southeast about 30 to 40 minutes before sunrise. You may be able to pick out Mercury below and to the left of Venus in the morning twilight during the first part of the month.
All times noted in the Sky Events are for Franklin, Tennessee and are in Central Standard Time. These times should be pretty close anywhere in the mid-state area.
Constellations: The views below show the sky looking east at 9:30pm CST on February 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.
Ursa Major, the Great Bear, is now prominent in the northeast. All of the bright stars of Leo, the Lion, are visible now, includingDenobola, the bright star at the tip of the Lion's tail. Part of the constellation of Virgo is visible below Leo. It's handy to know where Denebola is, because below it, if you imagine sliding down the Lion's tail, is the great Virgo cluster of galaxies. Look to the right of Denebola to find bright Jupiter. Left of Denebola, on a line towards the handle end of the "big dipper," you will see the faint star cluster Mellotte 111, in Coma Berenices. With a telescope, you can use the stars in this cluster to star-hop to the wonderful edge-one galaxy NGC 4565. The faint constellation of Crater has now cleared the horizon.
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 February. In particular, learn the brightest stars (like Regulus and Denebola 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 stars of Leo.
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 March 15th at 9:30pm CST, you can stay up till 11:30pm CST on the February 15th and get a preview. The westward motion of the constellations is equivalent to two hours per month.
Sky & Telescope's Pocket Star Atlas is beautiful, compact star atlas.
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.
The Virtual Moon Atlas is a terrific way to learn the surface features of the Moon. And it's free software. You can download the Virtual Moon Atlas here.
Cartes du Ciel (described in the monthly notes above) is a great program for finding your way around the sky. It is also free, and can be downloaded here.
Apps: We really love the Sky Safari Pro application described here. For upcoming events, the Sky Week application is quite nice. Both apps are available for both I-phone and Android operating systems. The newest version, Sky Safari 4, is available here.
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.
The amphibian season continues to build in February. One trick to finding amphibians in winter is to go out on mild (50 degrees Fahrenheit or warmer) rainy nights. It is important for safety reasons that you have another person with you to help watch for traffic as you slowly drive the back roads. Look for things that cross the road in front of you and stop frequently and listen. Early breeding frogs like Upland Chorus Frogs, Spring Peepers and Wood Frogs are already calling by the first of the month. On warmer nights listen for Southern Leopard Frogs. Spotted Salamanders and Tiger Salamanders also breed in January and February, and the eggs of both can often be found this time of year. Towards the end of the month, given mild temperatures, you can sometimes hear American Toads beginning to call. In west Tennessee, Crawfish Frogs give their loud snoring calls starting in late February and continuing on into early March. At higher elevations, listen for Mountain Chorus Frogs towards the end of the month. Remember that on mild nights you may find frogs and toads out foraging that you do not hear until later in the season.
Recommended: The Frogs and Toads of North America, Lang Elliott, Houghton Mifflin Co.
Many times when we have been out looking for amphibians in February we've witnessed courtship flights of the American Woodcock. Listen for the "peent" call at dusk and watch as the male Woodcock spirals upward till it's almost out of sight, then dives back to the ground, twisting and turning. This year, we heard our first "peent" call on January 31st. For more about watching American Woodcocks see, "The Woodcock's Call."
Red-Shouldered Hawks mate as early as February in Tennessee. Watch for courtship activities of these and other hawks.
Stick Nests: With the leaves down, this is a great time of year to find raptor stick nests. I make notes of all the nests I find and then periodically check them to see if anyone has "moved in." Many times Great Horned Owls make use of an old Red-Tailed Hawk's nest from the previous year. The owls can already be incubating eggs in January. Of the hawks, Arthur Cleveland Bent, in his "Life Histories of North American Birds of Prey," writes,
"[Red-tailed Hawks]...begin their nest building late in February or early in March; I have seen a wholly new nest half completed and decorated with green pine twigs and down as early as February 18th, over a month before the eggs are laid...Typical nests are from 28 to 30 inches in outside diameter, the inner cavity being 14 or 15 inches wide and 4 or 5 inches deep...The nests are well made of sticks and twigs, half an inch or less in thickness, and neatly lined with strips of inner bark, of cedar, grapevine or chestnut, usnea, and usually at least a few green sprigs of pine, cedar or hemlock. Some nests are profusely and beautifully lined with fresh green sprigs of white pine, which are frequently renewed during incubation and during the earlier stages of growth of the young...They "stake out their claim" late in February or early in March...by marking the nest they propose to use with a sprig of green pine...I believe that the birds prefer to build a new nest each year, but they sometimes use the same nest for consecutive years..."
Bent was writing about the Red-Tail Hawks in New England, so our times could be a little earlier.
You probably have already put out your bird feeders, but if you havenít you're missing out on a lot of good looks at winter feeder birds. This is a great time of year to start learning your birds. Watch and listen for winter residents such as White-throated and White-crowned Sparrows, Yellow-bellied Sapsuckers, Red-breasted Nuthatches, Golden-crowned Kinglets and Brown Creepers.
The Sibley Guide to Birds, David Allen Sibley
The Sibley Guide to Birds of Eastern North America, David Allen Sibley
An inexpensive guide for beginners is the Golden Guide for Birds.
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Natural Calendar December 2013
Nature Notes Archives: Nature Notes was a page we published in 2001 and 2002 containing our observations about everything from the northern lights display of November 2001 to frog and salamander egg masses.
Night scenes prepared with The Sky Professional from Software BisqueAll images and recordings © 2016 Leaps