July 2020 has been an amazing month, astronomically speaking. It started with a penumbral lunar eclipse. Then, the newly discovered comet (NEOWISE) put up a spectacular show in the northern skies. A week ago, Jupiter made its closest approach to Earth (opposition of Jupiter on July 14). And now, the most beautiful planet of our solar system is going to do the same on July 21. Here is everything you need to know about one of the most awaited events of July: 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.
Thus on July 21, Sun, Earth, and Saturn will lie along a straight line with Earth at the center. 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 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 of Saturn doesn’t vary over the course of conjunction and opposition.
2. How Close Will Be Saturn?
At the opposition, Saturn will be at a distance of about 1.34 billion Km (8.99 AU). This is about 67 million Km closer than the average distance from Earth. Even at its closest approach to the Earth, however, it is not possible 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.
3. How To Watch Saturn And Its Rings
Opposition marks the middle of the best time of year to see a planet. The Lord of the Rings will be visible shortly after the sunset rising around 20:08. For observers in the northern hemisphere, Saturn will rise in the south-east direction in the constellation of Sagittarius. It will reach its highest point in the sky at 00:28, 39° above the southern horizon. It will become inaccessible around 04:48 when it sinks below 10° above the south-western horizon. The apparent mag of Saturn will be 0.1 making it fairly bright.
In July, all the planets are visible in the night sky. It’s a rare event, the planet parade. Read this article to learn how to spot the planets. Also, these space apps will help you locate the celestial objects quickly.
Before you go, also read:
- How do neutron stars and black holes form?
- How to become an Astrophysicist?
- 10 of the best books on Astrophysics
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