Of all the planets, Saturn is the most spectacular. I call Saturn the rock star of the solar system.
The first time you see Saturn in the eyepiece and see those rings you should have a WOW moment. When showing the sky to friends, if Saturn is in the sky, start with Saturn.
First, let’s learn a little about Saturn
Saturn is named after the Roman god Saturnus, the god of agriculture and harvest. It is the second-largest planet in the solar system, after Jupiter, having a diameter approximately 9 times the diameter of the Earth.
Saturn orbits the Sun at an average distance of about 890 million miles. Saturn’s day is about 10.7 hours, a little less than half of our day. And Saturn’s year, the time it takes Saturn to orbit the Sun is approximately 29 Earth years.
Saturn is the sixth planet from the Sun. From Earth, Saturn is the third planet out, after Mars and Jupiter. When we are closest we are about 750 million miles apart. The light we see from Saturn comes from the Sun and the planet and rings reflect it back toward Earth. It takes almost 80 minutes for that reflected light to travel from Saturn to the Earth. So the image you see of Saturn is of Saturn 80 minutes ago.
When Saturn is the farthest from Earth, when it is on the other side of the Sun, we are over a billion miles apart. Naturally, when Saturn is on the other side of the Sun we can’t see it.
Jupiter and Saturn are called gas giants since they are made primarily of Hydrogen and Helium gas. Some scientists think that the gas giants may be failed stars.
We believe there is a rocky or metallic core to Saturn, but we don’t know for sure. We have not yet been able to probe deep into Saturn’s atmosphere to reach its core. The atmospheric pressure at the core would be so high that it would crush any probe that we might send there today.
Like Earth, Saturn’s axis of rotation is tilted. Earth’s axis is tilted 23.6 degrees to the solar plane. This is the reason we have seasons as we orbit the Sun. Saturn’s axis of rotation is tipped 26.7 degrees which means that Saturn will also experience seasons as it circles the Sun. It also means that, over time, Saturn’s rings will be seen from Earth at different angles.
Of course, the most prominent feature of Saturn is the rings, those beautiful rings. The rings extend 175,000 miles from the planet but are typically less than 50 feet wide. They are made up of ice, dust and small rock fragments. There are thousands of ring segments with gaps in between. The Cassini division is the largest gap, separating rings A and B. This division can be seen in most, but not all amateur telescopes.
Saturn has more than 60 moons, some of which are shown in the picture. Many more are intermixed with the rings. Some of the moons, called shepherd moons, actually help to form and establish a structure within the rings.
There have been four space missions that have visited Saturn. The most recent, Cassini, orbited Saturn from July 2004 to September 2017. Much of what we know about Saturn comes from this extended mission.
Observing Saturn
Saturn can be seen with the naked eye, even in very light-polluted locations. It is about as bright as the brightest stars.
Saturn is fairly easy to find when it is in the night sky. It travels along an imaginary line that extends from east to west across the southern sky. This is the same path that the Sun, Moon, and planets travel. So, note the path of the Sun and Moon, then look for Saturn to be traveling along that same path.
The picture below is a screen capture from the planetarium program Stellarium with the observer facing directly south, 180 degrees on the compass. As you can see, the ecliptic line is marked in orange. We see the Moon, Saturn, and Jupiter traveling along the ecliptic path.
Remember, Saturn is not always in the night sky and is not always visible from Earth. A quick internet search will reveal lots of programs, phone apps, and websites that will let you know when Saturn will be visible. Or you can use a planetarium program, like Stellarium, to view the changes in the sky to see when Saturn will be visible.
Using typical handheld 10X50 binoculars you can tell that Saturn is not a star as it appears to have a sort of an oval shape. This is not enough magnification to see the rings but enough to confirm you are looking at Saturn and not a star.
The best time to view Saturn is when it is high in the sky. At this time you are looking through the least amount of Earth’s atmosphere. Air pollution, dust, smoke, and moisture in the atmosphere scatter the light coming from Saturn. When we are describing the degree to which this scattering is happening we speak of the transparency of the atmosphere.
In addition, the atmosphere is always turbulent, which causes Saturn to drift in and out of focus. Think in terms of looking through a glass teapot of boiling water and trying to read a book that is located on the other side. We describe the degree to which turbulence is impacting our image of Saturn as the “seeing” conditions. Good seeing means the air is less turbulent. Bad seeing means it is very turbulent causing Saturn to drift in and out of focus.
Seeing and transparency conditions can vary greatly from day to day and hour to hour. So, if the view was great last week and poor tonight, the issue may be the atmosphere, not your telescope.
Local seeing can also be a factor. If you are viewing across a road, houses or commercial buildings, these release heat as they cool in the evening. This causes heat shimmers which will impact your view. As the evening goes on and these structures cool, the heat shimmers diminish. As a result, you may get better views in the evening or into the early morning.
What to Look for When Observing Saturn With Telescope
You can begin to see the rings of Saturn with at as little 30X magnification. However, to get a clear view of the separation of the rings from the planet requires higher magnification. We typically view Saturn, and all the planets at higher powers, over 100X and, depending on conditions and the telescope you are using, over 200X.
The greater the aperture of your telescope and the better the atmospheric conditions, the higher the magnification you can apply. But use good judgment as more magnification may give you a larger image but you may lose quality and detail.
The rings are often our first interest. Look for the planet to ring gap. Look for the Cassini division, shown in the earlier picture. See if you can see shading in the rest of the rings.
Saturn, like Jupiter, shows cloud bands in its atmosphere. They can be subtle but are visible with a telescope on clear nights at magnifications above about 75X. Because of its distance, the bands can be subtle but they are there. Some nights the atmospheric conditions might make it difficult to see the cloud bands. Other nights they may be quite evident.
Other than Saturn’s largest moon, Titan, Saturn’s moons are not visible with typical hand-held binoculars. However, a few of the larger ones can be seen in many amateur telescopes.
This screen capture from Stellarium shows the moons that might be visible in larger telescopes. But an aperture of 100 mm or larger may enable you to see at least a few of the moons, depending on the observing conditions. .
The moons will appear as pinpoints of light and are difficult to distinguish from stars. By using a smartphone app or a planetarium program you can see where the larger moons will be located in order to pick them out against the star background. And be aware that they move, orbiting Saturn, just as our moon orbits the Earth. So use the apps to see where they will be found tonight.
Filters
Many people like to use color filters to observe Saturn. These filters are often marked with numbers based on the Wratten system used for photographic filters.
Yellow-green, #11 can help to enhance the view of the Cassini division. Orange, #21 can help bring out the bands at the poles. Filters #23, red, #29 dark red, #38 dark blue, #56 LIght Green, #58, green, #80a and #82a, blue, can each help to enhance the cloud bands. If you have a set of color filters, experiment to see if you feel they help you.
Don’t expect dramatic changes based on the use of filters. Each filter may bring up a particular detail. It takes time and practice to make use of filters to see what they reveal.
Also, be aware that filters, by nature, absorb light, passing only some wavelengths to your eye. As a result, filters will darken the image. If you are using a fairly small telescope, say less than 120 mm in aperture, you may find that the benefit of certain filters may be overshadowed by the darkening of the image. Time and experimentation will help you discover which filters work best for you.
Perhaps you would enjoy a guided observing program. If so, consider the programs offered by the Astronomical League. They offer a program focused on the outer planets, Jupiter, Saturn, Uranus, and Neptune. If you work the program you can earn credit to achievement certificates.
https://www.astroleague.org/al/obsclubs/plantery/pocoutss.html
Summary
Of all the things there are to see in the sky, Saturn is often cited as the crown jewel. But whether you agree or not, Saturn is a spectacular sight offering beautiful views and observing challenges to help us hone our observing skills.
Clear skies and enjoyable observing!
