The solstice takes place on June 21 at 4:58 p.m. (peninsular time) and begins with a beautiful conjunction of Venus and Mars with the Moon. We offer you the 10 astronomical keys to the longest day of the year and the phenomena that will animate the sky during the summer period.
1. Home. Summer in the Northern Hemisphere (and winter in the South) will begin on June 21 at 4:58 p.m., official peninsular and Balearic time (3:58 p.m. in the Canary Islands). But be careful, not every year summer begins on this same day in June; for example: in 2024 summer will begin on the 20th. The variations from one year to the next are due to the fit of the sequence of years of the Gregorian calendar (some are leap years and others are not) with the real duration of an orbit of the Earth around the Sun.
2. Conjunction. The season begins with a beautiful conjunction of Venus, Mars and the Moon. To see it, you have to look to the west in the evening twilight, about two hours after the setting of the Sun, on June 21 or 22. The Moon is these days like a fine bright edge (the new moon took place on the 18th) and we can take the opportunity to observe the beautiful ashen light on the darkened part of the lunar disk.
3. Summer planets. Venus and Mars will continue to be visible in the evenings until they dip into the sun’s glare as they approach the king star in late August. Mercury will make a brief appearance between July and August. At dawn we will be able to continue observing Jupiter and Saturn, but the giant of the rings will disappear at the end of August, while Venus will then reappear at dawn in the east.
4. Three supermoons and one blue. The three full moons of the season will take place on July 3 and August 1 and 31. During these three full moons our satellite will be in a position close to the closest possible to Earth (perigee), it is what is sometimes called a ‘supermoon’. When a month has two full moons, the Anglo-Saxons call the second one a ‘blue moon’ (the fourth full moon of a season that has four is also called a ‘blue moon’). So the full moon on August 31 will be a ‘blue moon’, but of course this has nothing to do with the color of the Moon.