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 From March 2024

The family who owns the property I live on has been very gracious to me over the years, allowing me to place an observatory in an ideal spot and, when the planting season allows, use other good vantage points from the 500-plus acres that they have on Lookout Mountain.

I chose a hill on the farm that had a low northwest horizon to try for the comet. On March 2nd my attempts at photography were soundly defeated by wind gusts and my own klutzy mistakes. It was still a beautiful night though. I saw and heard a Short-eared Owl giving its raspy barking calls. My location also gave me a very low south horizon, and I saw the bright star Canopus hovering just over the horizon. Canopus is the second brightest star in the sky, being outshone only by Sirius.

I tried again on March 10th. As shown in the image above, clouds started moving in from the west at dusk, and I thought for a while that I would not be able to get an image. But ultimately the sky cleared in the northwest and I was able to get about thirty minutes of images before the clouds returned. Though the nucleus was only dimly visible in binoculars visually, the camera was able to reveal some details in the head of the comet, along with a short dust tail and a long ion tail.

The green glow in the comet's head is a result of solar radiation causing cyanogen and diatomic carbon to fluoresce. The yellowish dust tail of the comet is quite short and bends downward in the image. The long blue ion tails of comets always point directly away from the Sun. A finder chart showing the above image location and orientation is here. An annotated image showing myriads of faint PGC Catalog background galaxies is here.

The orbital path is shown at right in white, with the outer blue ellipse showing the orbit of Neptune. Farther investigation into the orbit of the comet and historical accounts of comet apparitions show that it most probably was observed in 1385 and in 1457. Since Brooks rediscovered it in 1883, the comet has returned in 1954 and in 2024 for its current apparition.

In some respects comets have fallen in stature from their 17th and 18th century heyday, when (before automated photographic discovery) visual observers often earned prize money for their discoveries. The French comet hunter Charles Messier created his famous Messier Catalog of "objects to avoid" when he chanced upon the Crab Nebula and was disappointed it was not a comet. Messier said, "This nebula had such a resemblance to a comet, in its form and brightness, that I endeavored to find others, so that astronomers would not confuse these same nebulae with comets just beginning to shine." Unknown to him, his 110-object catalog contains many of the most spectacular nebula, star clusters and galaxies in the sky. As late as the 19th century Nashville's legendary astronomer Edward Emerson Barnard built a house for himself and his wife using the money he received for discovering five comets.

Comet Pons-Brooks was definitely a challenge. The combination of its faintness, the necessity to shoot very close to the horizon through a lot of atmosphere, and the brief amount of time available before it set all contributed to the difficulty of getting a good image.

Using binoculars and the Sky Safari app we found the comet near the bright star Hamal in Aries. The comet nucleus was quite a bit brighter than it was on March 10th, but it still was not visible without binoculars. However, using binoculars, we were able to make out the ion tail of the comet extending upward from the nucleus for about two degrees. It was faint, but not hard to see.

The illustration at right shows our binocular view of the comet. There was a faint star not far from the comet's nucleus that was right in the path of the tail, and that made it easy to determine the exact angle it appeared relative to the horizon.

Comets are fascinating in that the details change from night to night as the solar wind buffets their tails. Whether you are observing them visually or through photography, you can see them change their position relative to the star field even in the course of one evening.

After Comet Pons-Brooks set on March 10th, I decided to relax a little bit and take an image where I wasn't racing the clock. One of the nice things about setting up a mostly automated telescope is that, once you are set up, it takes very little effort to do further imaging.

To the south, Orion was still free of clouds. I chose the Orion Nebula as a target and entered the number of images that I wanted to take. The telescope then slewed to the nebula, centered the nebula, started guiding, refocused and began the image run, all by itself. That left me free to enjoy the sky visually and listen to the chorus of Southern Leopard Frogs, Spring Peepers and American Toads calling from the pond below.

The sky was very clear around Orion and a lot of faint nebulosity is visible in the image. To see the nebulosity better the stars have been removed in the image below.

The brightest parts of the nebula can be seen with binoculars. Don't expect to see color. The light is too faint to trigger the color cells of our eyes except in very large telescopes. Given a clear moonless night, the area appears as a misty spot to the naked eye. A finder chart showing the image area and orientation can be found here, and an annotated image can be found here.

The spring migration of birds is underway, with new arrivals showing up just about every day. Year-round residents like the Eastern Meadowlark in the image below are singing more now. We photographed this one on March 22nd near Eagleville, Tennessee.

.We recorded this Louisiana Waterthrush, a neotropical migrant, on March 23rd.

Sky Events for April 2024:

Morning Sky:

Venus rises about 30 minutes before sunrise and may be visible low on the eastern horizon at the beginning of the month.

Mars rises higher into the morning sky as the month goes on. Look for it about 30 to 40 minutes before sunrise. Look for Saturn below and to the left of Mars. The two planets will appear closer and closer together each morning until the April 10th, when they will only be separated by about a half a degree.  Saturn will then pass Mars and the apparent distance separating the two planets will increase. On April 6th the two planets will form a pretty triangle with the waning crescent Moon. Mars will be within a tenth of a degree from Neptune on April 29th.

Constellations::

As spring progresses and Hercules rises higher in the sky, look for the globular cluster Messier 13, which appears like a small fuzzy patch of light about 1/3 of the distance from Eta to Zeta Hercules (see the chart below).  A cluster of stars about 21,000 light years away, M13 can be made out with the naked eye in a dark country sky when the constellation is high in the sky.  Binoculars will help pick it out. In small telescopes you can make out some stars around the edges of the cluster. It's a beautiful sight in a large telescope, and you can see a small shadowy three-sided feature (about the 4:00 o'clock position in the image above) nicknamed "the propeller."