SATURN – Appearance, Features, and Rings

 (This observing exercise is geared for middle and high school students.)


The appearance of Saturn through a telescope is stunning and spectacular. Its beautiful set of rings is an unforgetable sight!  In addition, the planet has a large disk with a few dark belts and light zones.  It is many moons of various brightness and distances.



1. The distinguishing feature of Saturn is its lovely set of rings. Although the rings appear to be solid, are they?


2. Explain two possible scenarios for the creation of Saturn's rings.


3. Why are Saturn's rings so bright?


4. Are the rings seen well? Are the rings highly inclined or nearly edge-on?


5. Is a gap in Saturn's rings visible? The largest gap is called Cassini's Division. What could cause such a gap?


6. How many moons can be counted? Which ones are they?


7. Explain why (a) all of the planets revolve around the Sun in one direction (i.e., counterclockwise as seen from above the Sun's north pole); (b) most of the planets revolve counterclockwise; and (c) most of the moons revolve in a counterclockwise direction around their respective planet.



1. Compute the degree of flattening.


Measured Longest Diameter   =  Diameter_long   =  _______________________

Measured Shortest Diameter  =  Diameter_short  =  _______________________

Oblateness  =  (Diameter_long – Diameter_short) / Diameter_long  =  ____________________


2. Compute the angular size of Saturn's rings.


Measured size of Rings (in cm)    =  Diameter_Rings  =  ____________________

Saturn-Earth Distance (in AU)      =  Distance_Saturn  =  ____________________

Saturn-Earth Distance (in cm)      =  Distance_Saturn  =  ____________________

Angular size of Rings (in arcsec)  =  Diameter_Rings / Distance_Saturn x 360° x 60 x 60  =  ____________________


3. Compute the linear size of Saturn's rings.


Measured size of Rings (in cm)  =  Diameter_Rings  =  ____________________

Saturn's Diameter (in km)           =  Diameter_Saturn  =  ____________________

Saturn's Diameter (in cm)           =  Diameter_Saturn  =  ____________________

Linear size of Rings (in km)         =  Diameter_Rings / Diameter_Saturn x 280,000 km  =  ____________________


4. Compute the distance from Saturn to the Earth in AU's, km, miles, and light-travel time (in minutes). Assume Saturn is at its nearest point to the Earth.


Earth-Sun Distance      =  1.0 AU

Saturn-Sun Distance    =  9.5 AU

Saturn-Earth Distance  =  9.5 – 1.0  =  8.5 AU

Saturn-Earth Distance  =  ____________________ km

Saturn-Earth Distance  =  ____________________ miles

Light Travel Time           =  ____________________ minutes



James Sowell, 2013