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Astr110 Photography Projects, Spring 2005

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Saturn, Brian Quarrella


In Roman mythology, Saturn was the god of agriculture, today we use Saturn as the root for the English word "Saturday." Galileo first observed the second largest planet in 1610, but it was not until 1659 that Christian Huygens correctly inferred the geomotry of its rings that make Saturn so unique. Their origin is still unknown. They are extremely thin (less than 1km thick) even though they are 250,000km in diameter. If every ring were compressed into one single object (as if you crunched a piece of paper up), then they would only be 100km across. From Earth, we are able to observe Saturn's most prominant rings, rings A, B, and C. Although from Earth we see these rings as one solid object, they are actually made of individual particles that have their own orbit. These particles range from being 1cm to several meters in diameter. A few amount of kilometer sized particles have been observed in the rings as well. These particles consist mostly of water ice, but these may be rocky particles with an icy coating. This makes many wonder how the rings stay in such a constant orbit. One main reason is because of its many moons. The moon Mimas is responsible for the lack of material in the Cassini Division, and the moon Pan is located inside of the Encke Division. This alone does not explain the rings' constant orbit, therefore; the entire subject is not understood to experts. Aside from its rings, Saturn is the least dense of all the planets in our solar system. It consists of 75% Hydrogen and 25% Helium with traces of water, methane, ammonia, and rock which is surprisingly similar to the composition of the solar nebula that our solar system formed from. Although there is no need to worry about Saturn forming a new solar system since its specific gravity is less than that of water (.7). Saturn is also extremely hot. Its temperature is 12000K at the core, and it radiates more energy than it receives from the Sun. The extra energy it receives to produce such a strong amount of energy is from the neighboring planet Jupiter. Still though, experts are unsure of why Saturn's luminosity is so large. In fact, it is so large we are able to see the planet from Earth with an unaided eye. Because of this, experts offer another explanation in which the core is "raining out" Helium.

In this particular photo of Saturn the glowing rings are extremely apparent. While Saturn is home to many rings, this photo allows for three rings to be distinguished clearly. These are the A, B, and C rings. The gap we see between the two closest rings of Saturn is called the Cassini Division. The other gap we see, although much fainter, is called the Enke Division. Other fainter rings can be observed although they seem to blend in with the more prominent rings. The orange reddish mixture of color we see is due to the high amounts of Hydrogen and Helium. We also observe that the Sun is behind Earth and above the right hand side of the planet. Looking at the photograph we see that the planet also casts a shadow on the rings on the lower left hand side. The distance from the Earth to Saturn at this specific date is 9.5AU.


The Nine Planets
Saturn's Ring System

Right Ascension 7:35:53
Declination 21:47:48
Filters used halpha (Ha), blue (B), visual (V)
Exposure time per filter

.1 seconds in HaBV

Date observed

April 5, 2005: BV, April 6, 2005: Ha