Do you remember the Great Conjunction of Jupiter and Saturn on 21 December 2020? The two gas giants came within 0.1 degrees of each other and could be seen as a double star in the evening sky. It was one of the most awaited astronomical events of the previous year. Planetary conjunctions are rare, but when they occur, it’s worth looking up in the sky. The month of July 2021 has one such rare conjunction of planets in its store.
This time, Venus and Mars will appear extremely close to each other in the evening sky of July 13. This article explains how to watch the celestial show. Also, make sure you have one of these space apps to locate the planets quickly according to the place you live.
What is a conjunction?
A conjunction is a celestial event in which two bodies appear to pass close to each other, as seen from the Earth. Although they appear close to each other in the sky, it does not mean they are in each other’s vicinity. On the contrary, they are millions of miles apart. They just happen to be at a reduced angular separation as seen from the Earth.
The Moon often passes by different planets in its 29-day cycle. But that’s not the case with the planets. Planetary conjunctions are rare. The last major planetary conjunction was the Great Conjunction of Jupiter and Saturn when the two bodies passed within 0.1 degrees of each other. Jupiter and Saturn were close enough to fit within the view of a telescope. On January 9-10, triple conjunction took place among Jupiter, Saturn, and Mercury.
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While the angular separation between Jupiter, Mercury, and Saturn has increased, the orbits of Venus and Mars are taking them close to each other, as seen from the Earth. On July 13, the two planets will lie 0°29′ of each other. Venus will pass to the north of Mars.
In astronomy, we quantify the brightness of a celestial object using a number called the apparent magnitude. Due to its logarithmic nature, the smaller the number, the brighter the object. For example, the Sun’s apparent magnitude is -26.74, while the brightest star in the sky shines at -1.46. An unaided human eye can see up to +6.0.
On July 13, Venus will shine brightly at a magnitude of -3.9 while Mars will be a faint speck of light at +1.8, both in the constellation of Leo. Look for them in the west as soon as the dusk sky fades. The brightest speck of light will be Venus. The pair will be close enough to fit within the field of view of a telescope but will also be visible to the naked eye or through a pair of binoculars.
Every year, there comes a time when all the planets of the solar system are visible in the sky on the same night (of course, not all together). In 2021, the first two weeks of July offer that window. The current configuration of the solar system is such that, as seen from the Earth, all the gas giants (Jupiter, Saturn, Neptune, and Uranus) have emerged from behind the Sun and are well up in the sky after midnight. Mercury, Venus, and Mars aren’t hidden in the Sun’s glare and can be seen with naked eyes. To learn how to see all the planets in the sky, please read this detailed article.