Telescope Night Information

Telescope Targets

Jupiter

Jupiter is seen here with its famous Great Red Spot, its largest moon Ganymede (top), its most volcanically active moon Io (right), and Io's shadow (dark spot on Jupiter).

Jupiter is currently located in Taurus, the constellation of the bull. At a mass of roughly 318 Earth masses, Jupiter is the most massive body in the solar system after the Sun. It takes Jupiter just under 10 hours to rotate; thus, one could observe the entire planet from the time it rises to the time it sets. Jupiter also has 95 known moons, and you can see up to four of the largest (the Galilean moons) on any given night including tonight. Jupiter also bears one of the most famous storms of all time – the Great Red Spot. This anticyclone has been observed for hundreds of years and was once large enough to swallow three Earths. Over time, the Great Red Spot has varied in color, shape, and size and is now only about the size of a single Earth.
Mars

Mars as seen with the Seyfert Telescope in January 2025.

Mars, the “Red Planet,” owes its orange hue to the presence of iron oxide (rust) in its soil. Tonight, you can spot the prominent ice cap at its north pole. The polar ice caps are made primarily of frozen carbon dioxide (dry ice), which is not surprising given that Mars’ thin atmosphere is also mostly carbon dioxide. As Mars goes through seasons, the polar caps change in size as ice sublimates in summer or atmospheric carbon dioxide freezes out in the winter. This can also stir up winds, which can lead to global dust storms. As winds move the orange dust around, darker surface features (mostly rock) can appear to change shape and size a bit over time. You can see some of these dark features tonight including the famous Syrtis Major region.
The Orion Nebula

A 4.5-hour composite exposure of the "sword" of Orion
From November to April, one of the favorite targets of both amateur and professional astronomers is the Orion Nebula. The 42nd object in Charles Messier’s list of non-cometary objects, the Orion Nebula is one of the brightest deep-sky objects in the night sky. Under dark skies, one can even spy it with the naked eye. The nebula lies about 1400 light-years away and spans about 24 light-years. Eyepiece views of the nebula typically show the inner, brighter region known as the Huygen’s region, named after Dutch astronomer Christiaan Huygens who provided the first known detailed drawings of the bright region in 1655. The nebula constitutes the central “star” in the dagger of Orion, which appears to hang below the famous three bright “belt” stars of the fabled hunter. At the center of the nebula is an asterism of four bright stars known as the Trapezium, which are estimated to be about three million years old. These stars are primarily responsible for illuminating the nebula, especially the most massive and luminous of the four known as Theta1 Orionis C. Just a few years ago, this star was discovered to be a binary star system with the primary component being a massive star some 33 times as massive as our own Sun and over 200,000 times as luminous. The intense radiation and stellar winds (particles streaming from the stars) from the Trapezium stars are in the process of blowing away much of the gas and dust in the nebula. Some models estimate that in as little as 100,000 years the nebula itself will be no more. Only a brilliant open cluster will remain, glittering like a jewel box in the eyepiece of a telescope much like the famous Pleiades star cluster.
The Clown Nebula

The Clown Nebula as seen with Dyer Observatory's Seyfert Telescope.
Found near the hip of the twin Pollux in the constellation Gemini, the Clown Nebula, formally known as NGC 2392, is a grand example of a planetary nebula. Despite the name, this type of object has nothing to do with planets save for a somewhat similar appearance to some of the planets in a telescope. What we are seeing is the remains of a small star that has met its demise. Though many mistakenly believe that all stars explode when they expire, the majority of stars are too small to go supernova in their final moments. Most stars, including our own Sun in five billion years, will go through a couple of stages of swelling to many times their original size, becoming red giants and then asymptotic giant branch (AGB) stars. At this point, the outer layers of a star are very weakly held by the gravity of the collapsed core and are gently lost to space over thousands of years. During this process, the white-hot core, known as a white dwarf, is exposed to space. The copious ultraviolet light emitted by the small core is absorbed by the expanding outer layers, causing them to fluoresce like a cosmic neon sign. This is precisely what is happening in NGC 2392 and others like it. The white dwarf, seen at the center of the nebula, is only the size of Earth but over 100,000 times as massive as our planet. A spoonful of white dwarf on Earth would weigh as much as elephant! NGC 2392 is about 1.5 light-years in diameter and lies approximately 6,500 light-years from Earth.

Key Points of Interest

The map below will provide locations for key points of interest in the observatory. If you have any questions, please don't hesitate to ask a staff member or volunteer.

Garland Collection - Many of the original astronomy instruments obtained by Chancellor Landon Garland in the 1870s for use in the first physics and astronomy classes of Vanderbilt University.
Star Model - An interactive model that displays information and positions of the 100 nearest and 100 brightest stars in the night sky as well as information about our own star, the Sun.
Fused-Quartz Mirror Disk - One of two original, uncoated test mirrors for the 200" Mount Palomar Observatory that were given to Vanderbilt University. One was originally intended to be used in a new telescope of Vanderbilt University.
Seyfert Telescope - On clear nights, the 24" Seyfert Telescope will be viewing a selected target. On cloudy nights, the doors will be open for visitors to see and learn about Dyer's largest telescope.
Hallway Images - Large infographics about galaxies, the Milky Way, and the life cycles of stars. On the opposite wall is a high-resolution panorama of the Milky Way with constellations and deep-sky objects highlighted.
HST Model & Planetarium Dome - Learn about the Hubble Space Telescope with the 1/5th scale model suspended in Dyer Observatory's original planetarium dome and experience the dome's acoustics.
AstroCantus - A combination of art and science, AstroCantus is a series of chimes that sound as the stars pass overhead. NOTE: The chimes may be muted - ask a volunteer.
ViewSpace Presentation - A presentation from the Space Telescope Science Institute. The program consists of continuous presentations ranging in length from five to 20 minutes and covering a variety of topics. Visitors may come and go as they please during the presentation.
Meteorites & Tektites - A collection of various types of meteorites and tektites.

Sky Chart for March 21, 2025

To use this sky chart, hold it up to the sky so that the direction labels are aligned with the cardinal directions. If you want to see what is in one particular direction, hold the chart out in front of you and rotate it so the label for the direction you are facing is at the bottom. For example, if you are looking north, then you will turn this chart upside down so that the “N” is at the bottom of the page.

The sky shown in the chart is what one would observe at the following dates and times:

March 6th – 9:00PM CST
March 21st – 9:00PM CDT (The Moon/planets are shown for this date)
April 5th – 8:00PM CDT

Deep Sky Objects

The objects listed in red are some of the brighter deep sky objects – objects that are outside of our solar system and aren’t single stars. These are just a few of the 109 Messier objects – bright “fuzzy” objects that Charles Messier noted positions of as he was scanning the sky for comets during the late 1700s and early 1800s. The 109 objects, each of which has a number preceded by a capital “M,” consist of star clusters, different types of nebulae (emission, planetary, and supernova remnants), and galaxies. These are among the brightest and most easily observed objects by both amateur and professional astronomers.

Stars and Constellations

This sky chart only shows a couple hundred stars that are visible to the unaided eye under dark conditions. Some of the brightest stars have their names shown in bold. Many others have names that were given to them by ancient astronomers, while others simply carry a catalog name/number. The apparent size of the dot representing a star tells you about its brightness – the brighter the star, the larger the dot. Sirius is the brightest star in the night sky.

The fall-winter sky contains a number of famous constellations that are visible from Tennessee. Many, such as Orion, Taurus, and Gemini, have Greek mythologies behind them. To the south are some not-so-familiar constellations, such as Antlia and Pyxis, which represent an air pump and mariner’s compass, respectively. In all, 15 of the southern constellations that are recognized by the International Astronomical Union (IAU) were established by French astronomer Nicolas-Louis de Lacaille during his expedition to the Cape of Good Hope in 1750.

General Information About the Sky

The ecliptic is the imaginary line that the Sun follows through our sky. In reality, this line is dictated by the orbit of the Earth. Since all of the planets of the solar system lie in nearly the same plane, one will observe the planets positioned very close to or on this line as well. Because the Moon’s orbit is tilted just a bit more than five degrees to this line, the Moon will not stray far from the ecliptic either. Some objects, such as comets, will not stay around the ecliptic. The constellations through which the ecliptic passes are the 12 famous zodiac constellations. There are, however, 13 constellations through which the Sun passes. For the first two weeks of December, the Sun is located in the constellation Ophiuchus, the serpent bearer.

There are 88 official constellations that cover the entire sky. Some are never visible from Tennessee as we are too far north; however, some, such as Ursa Minor and Camelopardalis, are circumpolar – they never get low enough in the sky to disappear below our horizon. The rest of the constellations are seasonal and visible in the evening sky for certain months of the year. Constellations are not just the stick figures we sometimes imagine connecting the brighter stars but are instead entire areas of the sky – everything is in a constellation. Objects outside of our solar system (stars, nebula, clusters, galaxies) remain in constellations, but the Moon, Sun, planets, comets, and asteroids all move through the constellations over time. Some famous star formations, such as the Big Dipper, Little Dipper, and Great Square of Pegasus, are not constellations – they are very recognizable parts of constellations known as asterisms. The Big Dipper, for example, is just a part of the constellation Ursa Major, the great bear.

Our Sun is just one of about 300 billion stars that make up our home galaxy, the Milky Way (shown in light grey in the sky map). In the late evenings of winter and summer, the Milky Way can be seen overhead. In the late summer, we are looking towards the center of the galaxy, which appears somewhat brighter. In the late winter, we are looking away from the center. Our solar system is situated on its side about halfway out from the center of this barred spiral galaxy.

When the Milky Way is easily visible, we have an opportunity to see many examples of the different types of objects found in the disk of a spiral galaxy. Spiral galaxies contain large amounts of dust and gas from which stars can form. As these clouds of material, known as nebulae, begin to collapse, denser pockets within the nebulae collapse faster to produce stars. When the stars begin to shine, they illuminate the clouds from which they formed. A prime example for late autumn to early spring is the Great Orion Nebula (M42), which forms the second “star” in the sword of Orion, the hunter. As time goes on and star formation uses up the remaining material of a nebula or disperses it, all that will eventually remain is a cluster of a few hundred to several thousand stars. These clusters, known as open clusters, are dominated by hot, blue-white stars and highlight the spiral arms of galaxies like our own. The Pleiades Cluster (M45), also known as “Subaru” or the “Seven Sisters,” is a beautiful example of such a cluster. The proximity of the cluster makes about six of its members easily visible to the unaided eye, but a low-power telescope will show dozens more.

The more massive a star is, the shorter its life will be. Massive stars therefore do not have enough time to venture far from the disk of the galaxy before ending their lives in spectacular supernovae. One such star, which was observed to explode in 1054 A.D., formed the Crab Nebula (M1). Most stars, however, are not massive enough to die explosively; instead, they puff up to become red giants and then gradually shed their outer layers over thousands of years. Once the core of the dying star is exposed, its ultraviolet light causes the shed layers to fluoresce, producing a beautiful planetary nebula. These nebulae have nothing to do with planets, rather their shape sometimes resembles the outer planets. Excellent examples of planetary nebulae are the Ring Nebula (M57), Clown Nebula (NGC 2392), and Cat’s Eye Nebula (NGC 6543).

During the late spring and autumn, the Milky Way appears closer to the horizon. Our galaxy, like all spiral galaxies, is shaped like a disk and is fairly thin compared to its width. As a result, when we see the Milky Way near the horizon, we are able to look up and out of our galaxy relatively easily to see objects outside of it. These include other spiral galaxies, like the Whirlpool (M51) and Andromeda (M31) galaxies, and spherical- to football-shaped galaxies known as elliptical galaxies, such as M87. Orbiting around these galaxies are globular clusters such as the Hercules Cluster (M13) and the Pegasus Cluster (M15). These clusters contain anywhere from a few hundred thousand to over a million stars in a small volume.