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 December 2015
The last part of December brought cascades of rain. This did not disturb our Upland Chorus Frogs. No one partied hardier during the holiday season than these little residents of our pond, and the last couple of weeks in the month were one long breeding chorus.
Earlier in the month we had clearer skies. This month brought quite a variety of photographic subjects, with an interesting assortment of both astronomical and earthly animals. In the astronomical realm we had a sea monster, a crab which really looks more like a rabbit, and a dark horse. Earthly subjects included an uncommon salamander and an uncommon goose. Distance from camera to subject varied from 8 inches to 10.4 billion light-years. Exposure varied from a 1/320th of a second to over 9 hours.
On December 2nd, 3rd and 4th, we had clear skies following a cold front. Every now and then we like to image something challenging, and we took the opportunity to image the small and faint galaxy NGC 1073. I like barred spiral galaxies, and this one is thought to resemble our Milky Way Galaxy.
I gathered about 9 hours of exposure on NGC 1073 and found that my camera position angle made it look a little like a reptilian eye. Perhaps the eye of Cetus, the Sea Monster? I often check objects that I image in the Simbad database, which compiles information about objects from many different sources and plots them. The Aladin applet on this page is particularly useful, though you will need Java. I found that I had unknowingly imaged three faint quasars.
quasar is a contraction of quasi-stellar object. When these
star-like objects were first discovered they were believed to be stars
within our galaxy that had very peculiar spectrums. It was
Schmidt of Cal Tech who made the intuitive leap. In the confusion of
spectral lines, he recognized, far out of place, the characteristic series
of lines for hydrogen. The position of these lines in the spectrum
indicated these objects were moving away at a tremendous velocity.
According to Hubble's Law, that in turn meant that quasars had to be both
incredibly far away, and incredibly bright. They are now believed to
be active nuclei of galaxies in formation, powered by supermassive black holes
at their centers. The farthest of the three quasars in the image,
called VV96 (far right) is about 10.4 billion light-years distant.
When the light we now see from this quasar had been traveling through space for
almost 6 billion years, our Sun had just begun to form!
We had another couple of clear nights on December 12th and 13th. I decided on both nights to image the relatively bright Crab Nebula in the early evening hours, then let the telescope gather light from the fainter Horsehead Nebula in Orion in the early morning hours.
On July 4th, 1054AD, a brilliant new star appeared in the constellation of Taurus, the Bull. In the early morning hours of July 5th it blazed beneath a slender crescent moon. According to Chinese records the "guest star" was six times brighter than the planet Venus and was visible in the daytime sky for 23 days. Native American pictographs in Chaco Canyon are thought by some to depict the event. The new star was visible in the evening sky for almost two years before it faded from view. For the next 700 years, nothing else was noted concerning the guest star. Then, in 1731, a physician and amateur astronomer named John Bevis spotted a small faint patch of nebulosity near zeta Taurus, which marks the tip of one of the bull's horns. He noted it on the star atlas he was preparing. Click here to see a detail of the atlas courtesy of the Linda Hall Library of Science, Engineering and Technology.
Charles Messier independently discovered the nebula 27 years later in 1758. Messier was searching for the comet predicted by Edmund Halley to return that year, and which now bears Halley's name. While searching for the comet, he spotted the same small patch of nebulosity that Bevis had seen. Messier initially thought he had recovered the comet, but when the nebulous object didn't change position relative to the stars, he knew he had been fooled. So this wouldn't happen again, he began a catalog of objects that were comet look-alikes. The nebula in Taurus became Messier 1, the first object in his new catalog.
Lord Rosse observed the nebula in 1844. Using the large Newtonian reflector at Birr Castle in Ireland, he thought the nebula resembled a Horseshoe Crab. Hence the popular name of the Crab Nebula. I have difficulty seeing a crab in the shape of the nebula. To me, the pale synchroton radiation looks like a rabbit, with the nose left and the tail right in the image above. The faint wisps of red and blue make my rabbit look like it's enveloped in a force field, a superhero rabbit.
It would be another 77 years before anyone connected the nebula to the brilliant star that appeared in 1054AD. In 1921, studies of photographs taken over a period of time showed a small but definite expansion of the nebula. Working backward, it was calculated that the nebula would have expanded from a point source around 900 years prior. It was Knut Lundmark who first noted the close proximity of Messier 1 to the bright star of 1054AD.
The "guest star" of 1054 AD had been a supernova. A star with a mass between 9 and 11 solar masses had reached the end of its life and exploded, leaving behind a cloud of debris and an incredibly dense core known as a neutron star. In the collapsed core, the mass of between 1 and 2 Suns is compressed into a sphere only 15 miles in diameter. The material of the star is so dense that one teaspoon of the star's material would weigh 12 trillion pounds. Or, to put it another way, imagine squeezing the entire mass of the Earth - its mountains, deserts, seas and cities - into a sphere slightly over 1000 feet in diameter. Then set it spinning as fast as the crankshaft of an idling tractor.
In 1949 Messier 1 was discovered to be a strong source of radio waves, and in 1959 it was found to be a powerful source of X-rays. In 1967, Jocelyn Bell, an English graduate student doing research with a radio telescope on quasars, discovered a new type of rapidly pulsating star. The new stars became known as pulsars. Soon afterward, a pulsar was discovered in the Crab Nebula. The neutron star at the center of the crab spins at a rate of 30.2 revolutions per second, and its incredibly strong magnetic field channels a beam of photons outward from each pole of the magnetic field. The Earth happens to be in the path of one of these beams, and the beam sweeps past the Earth 30.2 times per second. Bell and her colleagues named the first two pulsars LGM-1 and LGM-2. The letters stood for little green men, a tongue in cheek reference to the precise spacing of the signals. You can learn more about pulsars and hear Jocelyn Bell Burnell tell in her own words the story of one of the greatest discoveries of the 20th century here.
To see and learn more about the crab nebula's pulsar, including a composite x-ray and Hubble Space Telescope optical wavelength video clip, a "Lucky Imaging" video of the pulsar pulsing, and telescope finder charts, click here.
Just before I went to bed each night, I began imaging my second and more difficult target, the Horsehead Nebula. The Horsehead seems to have a mysterious quality to me - it's always a thrill to see it appear on my computer screen when the telescope is imaging.
The nebula is part of the Orion molecular cloud complex of nebulosity that extends through much of the constellation of Orion. It is listed in E.E. Barnard's catalog of dark nebulae as B33.
The Horsehead Nebula is not far from Alnitak, the easternmost star of the three stars in Orion's belt. Unless you are observing from pristine skies, seeing it visually usually requires a large telescope and a hydrogen beta filter, which allows a higher contrast view of the nebulosity. I've only seen it a few times, and never without the hydrogen beta filter. But it's always nice to have observing goals to fulfill!
The reddish nebulosity in the image is light emitted by hydrogen. There is also some reflection nebulosity created by light scattering off of dusty areas near bright stars, and of course the dark nebulosity, seen in silhouette. The Orion molecular cloud complex is an area of star formation about 1500 light-years distant. The dark form of the Horsehead extends about 3 light-years in its longest dimension.
Before we leave the Horsehead, be sure to check out the spectacular image in infrared light taken by the Hubble telescope!
On December 17th we searched along Overall Creek in Rutherford County for an uncommon salamander that breeds this time of year. Streamside Salamanders, Ambystoma barbouri, are found in Tennessee only in the Central Basin and are Deemed in Need of Management.
Our small team consisted of Andrea and Susan from TWRA, myself, and Kristin from Owl's Hill Nature Sanctuary. This was our second try at finding the salamanders along this creek, and there were no prior records here. The salamanders lay their eggs beneath rocks in the stream. Kristin spotted the eggs (fitting, since she proposed searching this particular creek) and I quickly took some images. The field of view in the above image is not much bigger than a postage stamp.
Finally, on the way back home after finding the Streamside Salamanders, we stopped to check out a group of small geese foraging in a grassy field along Highway 96. I had noticed the group on the way down, and on the way back used a pair of borrowed binoculars to get a better look. They turned out to be six Ross's Geese, a species that is uncommon in Tennessee. I went home and got my Televue 85 refractor and came back. Susan also stopped by and we managed to get some images just before sunset.
This species is quite small for a goose, only about Mallard-sized. The bill is shorter than the similar but larger Snow Goose, and there is a darker blue-gray area at the base of the bill.
The first Ross's goose was found in Tennessee only in 1986, but more seem to be showing up in the last few years. It's still always a thrill to find them.
Sky Events for January 2016:
Earth is at perihelion, nearest the Sun, on January 2nd.
At the beginning of the month, Mercury is about ten degrees above the southwest horizon about 30 minutes after sunset. It will quickly disappear into the twilight glow the following week. Binoculars will help pick it out.
Jupiter rises about 10:24pm 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 4:41am.
TheQuandrantid Meteor Shower peaks around 2:00am on January 4th. This shower has a very brief peak of several hours. Look to the northeast.
The trend for holiday comets seems to continue this year. Though it will not be spectacular by any means, you may want to follow Comet Catalina (C/2013US10) as it makes its way across the early morning sky in January. It's not supposed to get much brighter than 5th magnitude, so you'll need binoculars to spot this little faint fuzzy. This comet's position is shown in the Sky Safari app shown in the reference section below.Mars is in Virgo as the month begins, rising about 1:19am. Mars is still quite small in the eyepiece, only about 5.6 arc-seconds in diameter. The red color is easily visible in binoculars.
Venus rises about 4:02am in Scorpius at the beginning of the month and is dazzling in the eastern sky before sunrise.
Saturnis low in the southeast before sunrise at the beginning of the month. Look for it below and to the left of Venus as the month begins. The two planets are less than 1/2 degree apart on January 9th. After the 8th, look for Saturn above and to the right of Venus.
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 January 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, has now cleared the horizon in the northeast. The bright stars of Leo, the Lion, are visible now. Hydra, the Water Serpent, rears its head menacingly. Hydra's brightest star Alphard is known as "The Solitary One" because of its somewhat isolated location from other bright stars. Canes Venatici, the Hunting Dogs, also makes its appearance just above the northeast horizon. Among the fainter constellations visible in the east are Leo Minor, the Small Lion, Cancer, the Crab, and Sextans, the Sextant. Look below Pollux and see if you can spot the faint glow of M44, the "Beehive Cluster." This cluster is located in Cancer, the Crab.
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 January. In particular, learn the brightest stars (like Regulus 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 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 February 15th at 9:30pm CST, you can stay up till 11:30pm CST on the January 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 April 15th at 9:30pm CST (3 months later), you would need to get up at 3:30am CST in the morning on January 15th (3 months times 2 hours/month = 6 hours).
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.
A lot of things happen with amphibians in January. To see them, though, you have to be out in the sort of weather that makes most people stay indoors. The trick is to go out on mild (50 degrees Fahrenheit or warmer) rainy nights. For safety, it is important that you have another person with you to watch for traffic as you slowly drive the back roads, looking for things that cross the road in front of you. Make frequent stops to listen for calling frogs. In January, both Spring Peepers and Upland Chorus Frogs are not uncommon, and Wood Frogs have their short-lived breeding choruses in woodland ponds. Southern Leopard Frogs are also sometimes calling on mild January nights. We have seen Northern Cricket Frogs, Green Frogs, American Bullfrogs and American Toads foraging in January. And just about anything is possible. On January 22, 1999, we found an Eastern Spadefoot out in the stormy weather. That same day a tornado ripped through Clarksville, Tennessee, doing much damage to the Austin Peay campus. January is an exciting time of year to look for herps!
This is also the time to look for Tiger Salamander and Streamside Salamander egg masses. Tiger Salamanders like to deposit their egg masses on the vegetation in shallow water in small ponds and wetlands. Streamside Salamanders deposit their egg masses on the bottoms of rocks in streams. If you are looking for salamanders, always remember to carefully replace any stones you pick up exactly where you found them.
Recommended: The Frogs and Toads of North America, Lang Elliott, Houghton Mifflin Co.
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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