The first time you see Saturn in the eyepiece and see those , 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 nine 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 ours. 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. Saturn orbits the Sun in a near-circular orbit ten times the distance away that Earth does, and it takes 29.5 years to complete one orbit around our star. When we are closest to Saturn, we are over a billion kilometers (750 million miles) apart. The light we see from Saturn comes from the sun, and the planet and its 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 from 80 minutes ago. When Saturn is the farthest from Earth, when it is on the other side of the Sun, we are over 1.6 billion kilometers (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. The 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 thick. 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.
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.
How and When to Find Saturn in the Night Sky
Saturn can even 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 the ecliptic plane, 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 paths of the Sun and Moon, then look for Saturn to be traveling along that same path. For most of the year, Saturn can be seen in the night sky, although its specific location varies depending on the time of year.
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.
One of the best times to see Saturn is during the weeks and days around its opposition, which is when Earth is positioned directly between Saturn and the Sun. During opposition, Saturn is about at its closest to Earth, making it appear brighter and larger. It also rises at sunset, reaches its highest point in the sky around midnight, and then sets at sunrise. This means that it’s visible all night long. Oppositions of Saturn occur roughly once every year—every 378 days, to be more precise. By checking an astronomical calendar or using a stargazing app such as SkySafari, you can find the date of Saturn’s next opposition and plan your stargazing accordingly.
The next opposition of Saturn occurs on August 27, 2023. It will remain visible in the evening sky after sunset for several months afterwards until it sinks into the glow of the Sun, reaching superior conjunction (its furthest away, on the opposite side of the Sun) on February 28, 2024, and re-emerging in the pre-dawn sky sometime in late March. Saturn will reach opposition again on September 27, 2024.
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 Earth’s 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 “seeing” conditions. Good sight 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 shimmering heat diminishes. As a result, you may get better views in the evening or early morning.
What Size Telescope Do You Need to See Saturn?
Using typical handheld 10X50 binoculars, you can tell that Saturn is not a star as it appears to have a sort of oval shape. This is not enough magnification to see the rings, but enough to confirm you are looking at Saturn and not a star. You can begin to see the rings of Saturn with as little as 20-30x magnification. However, to get a clear view of the separation of the rings from the planet, it 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.
What to Look for When Observing Saturn With Telescope
One of the most spectacular sights when observing Saturn is the shadow the planet casts on its rings. This feature is relatively easy to spot, even with a small telescope. The visibility of the shadow varies with Saturn’s season, which is determined by the tilt of the planet’s axis and its position in its 29.5-year orbit around the Sun. When Saturn is near its equinox, the rings are edge-on to the Sun, and the planet’s shadow on the rings is a thin line just along the rings. Near Saturn’s solstice, the shadow extends across the rings, creating a dark wedge that can be easily observed. The shadow adds a stunning three-dimensional quality to views of Saturn and serves to highlight the planet’s complex ring system.
The Cassini Division is one of the most remarkable features of Saturn’s ring system that can be observed from Earth. Named after the Italian-French astronomer Giovanni Domenico Cassini, who discovered it in the 17th century, the Cassini Division is a gap approximately 4,800 kilometers wide between the A Ring and B Ring. Despite being called a ‘division,’ it’s not empty but contains a much lower density of ice particles compared to the adjacent rings. When the rings are at their maximum tilt, even a 3” (76mm) telescope shows Saturn’s Cassini Division. As of 2023, with a ring plane crossing less than 2 years away, the Cassini Division often requires a considerably larger (4” or greater) instrument and above-average conditions to be resolved easily.
Unlike the vast Cassini Division, the Encke Gap is a narrower feature, spanning about 325 kilometers in width. It’s not empty but houses the small moon Pan, which is approximately 28 kilometers in diameter. Pan acts as a shepherd moon, clearing the gap through its gravitational influence. The particles within the gap form a faint ringlet due to Pan’s gravitational nudges. The Encke Gap can be seen with an 8” or larger telescope under ideal conditions, but a 10” or bigger telescope is ideal. An 8” or larger scope can also resolve the thinner (270 km) Maxwell Gap on an exceptional night with extremely good optics and a keen eye.
Much like its larger neighbor, Jupiter, Saturn exhibits a system of cloud belts visible on its disk, which are organized layers of circulating gases at different latitudes. These belts, however, are not as readily observable as Jupiter’s due to Saturn’s higher, thicker haze of atmospheric methane. Saturn also lacks the dramatic storms Jupiter frequently exhibits, and most of the bands are nearly perfect straight lines. Nonetheless, with a good-quality telescope, one can discern the alternating pattern of these lighter and darker bands. The most easily visible band is a dark equatorial belt, while subtler bands can be perceived under ideal viewing conditions or with the aid of quality color filters.
Observing the Moons of Saturn with a Telescope
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 with many amateur telescopes.
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.
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.
Observing Saturn’s moons with a telescope is a delightful activity for amateur astronomers. With a modest telescope, viewers can easily spot the bright pinpoints of light belonging to Saturn’s largest moons. Often, the moons are difficult to distinguish from the 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. Titan, being the largest, is easily visible even with small telescopes or high-powered binoculars. Iapetus, Rhea, Dione, and Tethys are also discernible under good conditions and with a moderate-sized telescope of 3” or greater aperture. More difficult to see are the small and close-by Mimas and Enceladus, though a 6-8” telescope usually reveals these.
Observers will notice that the positions of these moons change from night to night as they orbit Saturn, providing a fascinating display of celestial dynamics. Titan shows a yellowish-orange disk with 10” or larger instruments; the other moons remain pinpoints.
In 2025, the orbits of the larger moons of Saturn and the planet’s rings will appear edge-on, thus opening up the possibility of transits like those of Jupiter. However, most of the moons are too small to resolve with typical amateur telescopes under normal conditions. The exception is, of course, Titan. Titan will transit across Saturn, often casting a shadow, with 13 of these occurrences visible between May and November 2025, though you’ll need Saturn to be above the horizon at the time of the transits, which may or may not be the case for many of them at your location.
Besides the main circular moons, other Saturnian satellites can be seen by skilled observers with sufficient gear. Hyperion tumbling at approximately 15th magnitude is best seen with a 12” or larger telescope, while Phoebe at approximately magnitude 16 requires at least 16” of aperture along with clear, dark skies. During the weeks when Saturn appears edge-on in 2025, there also exists the opportunity to spot a few shepherding moons such as Janus and Epimetheus, nominally bright enough but physically blocked as well as washed out by the brightness of the rings – though all are dimmer than 14th or 15th magnitude and will require a fairly large instrument to be spotted.
Telescope Color Filters for Observing Saturn
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. Most of these filters have a negligible effect – Saturn simply doesn’t have a lot of contrasty atmospheric detail, and filters don’t work much on the rings – but they can be of some use. A Baader Contrast Booster or Baader Fringe Killer is indepensible on Saturn if you own a refractor, unless it is extremely well-corrected.
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 and 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 is overshadowed by the darkening of the image. Time and experimentation will help you discover which filters work best for you.
Conjunctions and Occultations of Saturn
Saturn regularly appears in conjunction with other planets in the night sky due to its alignment with the ecliptic plane. Occasionally, these are close conjunctions where both objects will fit in the same telescopic field of view. An exceptional one of these occurred when Jupiter and Saturn approached closely in the evening sky in late December 2020. Unfortunately, Saturn doesn’t approach any planets closely for the next couple of years as of the time of writing (2023), apart from an encounter with Venus low in the pre-dawn sky on March 21st, 2024. There will also be a few distant passes by Neptune in 2025, when the ringed planet will be about 1 degree away from the ice giant in the sky (and thus visible together at low magnification), and for the most part, stays close by it for most of the year owing to the slow movement and great distance of both giant planets.
More frequent are lunar occultations and conjunctions, where Saturn frequently appears very close to our Moon or is hidden by it. These events are a thrilling spectacle to witness. Many of these will be visible in 2024 through January 2025, and the next set will not occur until 2031, so be sure to catch a glimpse of at least one! Saturn’s rings are nearing edge-on but will still be visible during these events. If you’re outside the occultation path, you’ll still get to see a very close conjunction between our Moon and the ringed planet.
Saturn also enters conjunction with the Sun approximately once every 378 days between oppositions, when it is unobservable and at its furthest from us. During these periods, known as superior conjunctions, Saturn is on the far side of the Sun from the Earth, rendering it invisible in the Sun’s glare.