Focus On Observing Saturn

For any telescope;  Updated February 2006

February finds the most spectacular of the planets well placed for evening observation.  Look for it as the bright yellowish "star" rising high in the east at sunset.  Saturn is in the constellation Cancer just west of the Beehive cluster.

Saturn offers more than just those spectacular rings: observers can try for a glimpse of atmospheric features, view gaps in the rings, and search out the tiny moons--all of which provide interesting challenges for scopes both large and small.  Saturn is in a fairly dense field of stars this month, providing a pretty backdrop against which to watch the planet move.  Many stars will pass near the planet making it more difficult to be certain you have seen a moon.  There are also many opportunities to watch various moons pass close to background stars.

Saturn in February

Size Magnitude Con Distance From Earth Visible Moons
20' x 16'
 -0.4 Cnc
8.2 AU
8


The Satellites of Saturn


Saturn offers eight satellites that are visible in amateur instruments.  Smaller telescopes will reveal the four brightest moons; seeing all eight is a challenge for the largest telescopes.

The following table lists the relevant data for the moons of Saturn in order of easiest to hardest to observe.  Iapetus varies in brightness with the side of saturn it is on.  It is brightest when west of the planet.  The required scope column is only meant as a guide -- it may be possible to see some satellites in smaller scopes under good conditions.  Hyperion is not only faint, but it is a technical challenge because it wanders so far from the planet that you need excellent charts to know which "star" it is.  Mimas is difficult in any telescope because it is both faint and very close to the planet.

 

Satellite

Mag.

Max. Elongation

Orbital Period

Req. Scope

Titan

8.1

3'17"

15d 23h

Any Scope

Rhea

9.5

1'25"

4d 13h

2"

Dione

10.2

1'01"

2d 18h

2"

Iapetus

10.9-12.4

9'35"

79d 8h

3"-6"

Tethys

10.0

48"

1d 21h

6"

Enceladus

11.5

38"

1d 9h

6"

Hyperion

14.0

3'59"

21d 7h

8"

Mimas

12.7

30"

22h 37m

16"?


Finding a moon near the limit of your telescope requires good seeing and knowing where the moon is relative to the planet.  Saturn should be high in the sky when you observe it.  Use high magnification for those moons closest to Saturn.  A well-baffled telescope greatly enhances your chance of success for these by reducing the scattered light from the planet.
 

Observing the Rings


Saturn's rings are among the most spectacular things you can view in a telescope.  It's easy to get so caught up in the view as to forget to really look.  The first thing to look for is the shadow of the rings on the planet.  Also notice the shadow of the planet on the rings.

Another major feature is the the main gap in saturn's rings, called the Cassini division.  It can be spotted on nights of good seeing in even the smallest telescopes (3"). Look for it about 3/4 of the way out from the inner edge.  The ring to the outside of this gap is called the "A" ring.  The brighter ring that lies to the inside is called the "B" ring.

Another division, commonly referred to as Enke's gap, is much narrower and more difficult to see.  Look for it near the outer edge of the "A" ring, about 7/10 of the way out.

Another elusive target is the "C" or "Crepe" ring.  This ring lies just inside of the B ring.  Look for it in silhouette, as a darkening of the planet to the inside of the "B" ring.  This ring can sometimes also be glimpsed as a very slight brightening to the inside of the B ring away from the planet's disk.
 

Atmospheric Detail on the Planet Itself


The atmosphere of Saturn has details much like those of Jupiter, only less obvious.  Look for dark and light bands, small white ovals, dark areas and even festoons.
 

                     

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