Saturn has a beautiful halo. It is a ball of joy in the eyes of astronomy fans and is loved by the general public. Saturn is currently in Capricorn. Since early July, it will rise from the southeast in the evening. When it reaches the "opposition" position at 1:10 on August 15, Saturn and the sun will be on both sides of the earth. yellow longitude are about 180 degrees apart. At this time, the brightness is mag 0.3 and the apparent diameter is 18.8 arc seconds. The few weeks before and after Saturn's opposition to the sun are the best times to observe Saturn. It is the period of the year when Saturn is the brightest, has the largest apparent diameter, is relatively close to the earth, and can be observed all night long. Astronomy fans can take advantage of this period. period.
Schematic diagram of Saturn in Capricorn in mid-August 2022
What is "opposition"? Through the two-dimensional planetary orbit diagram, for outer planets, "opposition" is the period of the year when they are closest to the earth. When the planet reaches the "opposition" position, it means that the planet is visible all night long and is most convenient for observation; when the planet is away from the Earth, When the earth is at its farthest, it is called "conjunction". The planets and the sun rise and set at the same time. At this time, the planets cannot be observed. When the planet, the earth and the sun are connected to form a right-angled triangle, it is called "square illumination". When viewed from the earth, when the planet is on the east side of the sun, it is called east illumination, and vice versa.
For observers on the earth, Saturn reaches the "opposition" position almost every year, but the revolution period of Saturn is 29.4 years. Every year when the earth wants to catch up with Saturn, it must go a little further in its orbit for Saturn to happen. Opposition sun. Therefore, Saturn opposition occurs approximately once every 378 days, resulting in the Saturn opposition occurring approximately two weeks later each year.
When Saturn opposes the sun at 1:10 on August 15, 2022, Saturn is in Capricorn. It rises from the southeast after sunset and sets from the southwest before dawn. Its brightness is close to Vega , about 0.3 magnitude, which can be seen clearly with the naked eye. Seen as grayish-yellow star points. The apparent diameter of Saturn is 18.8 arc seconds, but the rings can reach 43.7 arc seconds, which is close to the size of Jupiter . It can be seen with a 30x small telescope. The clouds on the surface of Saturn can also be seen with a larger aperture and high magnification telescope. Details such as Cassini ring gaps in the belts and rings of Saturn.
Saturn, Saturn's rings (top) and changes in Saturn's rings in the next few years (bottom).
Since the angle between Saturn's rotation axis and its orbital plane is about 26.7 degrees, and the inclination of Saturn's orbital plane is about 2.5 degrees, the inclination of Saturn's rings relative to the Earth changes periodically, with a period of 13 to 15 years, about the orbital period of Saturn. half. On May 22, 1995, August 10, 1995, February 11, 1996, and September 4, 2009, the equator of Saturn was facing the Earth, the inclination of the rings was 0 degrees, and the rings were in a straight line. The next occurrence will be March 23, 2025. Therefore, astronomy fans who want to appreciate the rings of Saturn must not miss this Saturn opposition. Use the small astronomical telescope to observe the beautiful rings of Saturn; for advanced astronomy fans, on a clear night with stable airflow , you can challenge to observe the Cassini Gap, which is the darker area separating the A ring and the B ring. It was discovered by Cassini as early as 1675.
In addition, Titan (Titan) is another focus of observation. Saturn currently has at least 83 satellites with confirmed orbits. Among them, Titan is the largest satellite of Saturn and the second largest satellite in the solar system. Titan's brightness is about 8.0 when it is in opposition to Saturn, and its apparent diameter is about 0.8 arcseconds. When observed with an astronomical telescope, it is relatively easy to see it showing bright orange light.
The positions of Saturn and Titan at 1:00 on August 15, 2022
