Saturn, the solar system's "Lord of the Rings," is back in the early evening sky. The planet is at opposition on Monday, which means the planet is opposite the sun and closest to Earth.
Due to its position, Saturn is in the sky all night long. As the sun sets, Saturn is rising in the southeast. Although it rises at 8:21 p.m., wait at least an hour for it to rise higher in the sky. The best time to view is after 10 p.m. when Saturn is more than 15 degrees above the southeast horizon. It is highest in the southern sky around 1 a.m. and can be seen sinking in the southwest at 4:30 a.m.
At a distance of 841 million miles, Saturn is closest to Earth now. Its proximity makes it quite bright, but not as bright as Jupiter. It is as intense as the bright summer star Vega, which you can see rising in the east.
Saturn is visible in the southeast sky after sunset. It is in the constellation Ophiuchus but is located near the bright stars of Scorpius.
Saturn is at the southern edge of the large faint constellation Ophiuchus, but a brighter more recognizable pattern of stars lies nearby. Look to the right of Saturn for the upper part of Scorpius the scorpion. The bright red star here is Antares, the heart of the scorpion.
Saturn is one of four gas giant planets in our solar system. Here are some interesting facts about the sixth planet:
- It has no solid surface
- Its day is only 10 hours 33 minutes long
- Saturn orbits the sun once every 29.5 Earth years
- 764 Earths could fit inside Saturn
- Saturn is 95 times the mass of the Earth
- It has 62 moons
The Rings at Maximum
Saturn's most prominent feature is, of course, its rings. The planet has seven main rings and an eighth dusty outer ring. Although the main rings are almost 175,000 miles in diameter, they are very thin. The rings vary from about one-half mile to less than 100-feet thick. They are made of billions of orbiting particles. These particles are largely water ice (about 93 percent) with the remainder composed of dust and other materials.
Given the large size of the rings, they are easy to see through backyard telescopes. Almost any small telescope and a magnification of 25 to 50X should give you at least a glimpse of them. 100X or more will give you a better view. One thing to look for is the Cassini Division. This is a separation between ring A and B. Saturn's ring system has almost a dozen gaps, but the Cassini Division is the easiest to see. You will need a telescope larger than 4 inches and a magnification of 100 to 150X to view it.
These Hubble Space Telescope images, captured from 1996 to 2000, show Saturn's rings open up from just past edge-on to nearly fully open as it moves from autumn toward winter in its Northern Hemisphere. This pattern repeats every 15 years.
Saturn's axis is tilted 27 degrees. Due to this tilt, the appearance of the rings changes dramatically. In 2009, the rings were edge-on to us, and therefore almost invisible. Since then the planet's tilt has allowed us to see the northern face of the rings. The rings have "opened up" over time and now are at maximum visibility. During the next several years the rings will appear to close again until they are edge-on in 2025.
The Clouds
When viewing Saturn in a telescope, details on the planet's disk are more difficult to see. It has some of the same bands of clouds as doesJupiter
but they are much more subtle. You will likely need a telescope 6 inches in diameter or larger to get a good view. The clouds here appear as pale whitish-yellow bands. Some stargazers have found that using a yellow filter improves the appearance of these cloud bands.
The Moons
Sixty-two moons obit Saturn - a number second only to Jupiter with 69. Many of these satellites are so small they can only be seen by space probes. However, Saturn's largest moon, Titan, is big enough it can be spotted in binoculars. It looks just like a bright star next to Saturn, but over time you can watch it move in its orbit around the planet. It completes one orbit in 16 days. Tonight Titan is located east of the planet.
The position of some of Saturn's moon for tonight. Titan is the easiest to spot.
With a larger telescope, say 6-to-8 inches in diameter, you may be able to spot Iapetus, Rhea, and Dione. You will need to know where and when to look, so use Sky & Telescope's Saturn Moon Utility and apps. Note that when looking through a telescope, the images often appear upside down, backwards or both, depending on your equipment.
We have a nice long time to view Saturn, as well as Jupiter. These two gas giants will remain visible in the early evening sky through much of the summer. Enjoy!
Kevin D. Conod is the planetarium manager and astronomer at the Newark Museum's Dreyfuss Planetarium. For updates on the night sky, call the Newark Skyline at (973) 596-6529.