After putting up a spectacular celestial show on the day of the December solstice last year, Jupiter and Saturn are in the news again. In August, the two gas giants of the solar system will make their closest approach to Earth and shine brightly in the night sky. It’s the best time of the year to see the planets with naked eyes. Here is everything you need to know about the opposition of Saturn.

1. What is an opposition?

In celestial mechanics, a planetary opposition occurs when the Earth lies between the Sun and the planet, with Earth being on the same side of the planet, as shown below.

Saturn Will Make Its Closest Approach To Earth This Week. Here's How To See The Ringed Planet. 1
The concept of opposition and conjunction in astronomy

Thus on August 2, Sun, Earth, and Saturn will almost align, with Earth in the middle. This optimal positioning occurs when Saturn is almost directly opposite the Sun in the sky. Since the Sun reaches its greatest distance below the horizon at midnight, the point opposite to it is the highest in the sky at the same time.

At around the same time that Saturn passes opposition, it also makes its closest approach to the Earth – termed its perigee – making it appear at its brightest and largest. However, Saturn’s orbit lies far out in the solar system, at 9.5 AU, and hence the angular size doesn’t vary much over the course of conjunction and opposition.

2. How close will be Saturn?

On August 2, Saturn will be at a distance of about 1.33 billion km (8.94 AU). This is about 66 million km closer than the average distance from Earth. Even at its closest approach to the Earth, however, it is impossible to distinguish it as more than a star-like point of light with the naked eye, though a good pair of binoculars is sufficient to reveal its rings with an accompanying system of moons.

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Saturn Will Make Its Closest Approach To Earth This Week. Here's How To See The Ringed Planet. 2
At opposition, the planet appears slightly bigger, as seen through a telescope (Image: in-the-sky)

3. How to see Saturn and its rings

Saturn Will Make Its Closest Approach To Earth This Week. Here's How To See The Ringed Planet. 3
Looking southeast around 22:00 (Image: Stellarium Web)

Opposition marks the middle of the best time of year to see a planet. The ringed planet will be visible shortly after the sunset, around 20:00. For observers in the northern hemisphere, Saturn will rise in the south-east direction in the constellation of Capricornus. It will reach its highest point in the sky at 00:30, 42° above the southern horizon. It will become inaccessible around 04:56 when it sinks below 10° above the south-western horizon. The apparent mag of Saturn will be +0.2, making it fairly bright. You can use these space apps to locate Saturn according to your place quickly.

The apparent magnitude of a celestial object is the measure of its apparent brightness. The smaller the number, the brighter the object. Unaided human eyes can see up to +6.0.

What’s more in August 2021?

About three weeks after Saturn, Jupiter will be at opposition on August 20. Jupiter is visible in the sky, a little away from Saturn. Please do not confuse it with Saturn. Out of the two, Jupiter shines brighter. Besides these two flagship planetary events, August has the best meteor shower in its store. The Perseid meteor shower will peak on August 12-13, producing up to 150 meteors per hour under completely dark skies.

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