Astronomy Calendar: Best Night Sky Events of Summer 2021

~6 min

The June solstice, which occurred on June 21, 2021, marked the beginning of the new astronomical season: summer in the Northern hemisphere and winter in the Southern part of our planet. In this article, we've gathered must-see stargazing events that you wouldn't like to miss this new season.


Meteor showers

July 28-29: The Delta Aquariid meteor shower

Don't miss the opportunity to enjoy the spectacular night sky view in late July, when the Delta Aquariid meteor shower reaches its peak. The Delta Aquariids are active from about July 12 to August 23, peaking on July 28-29. At its peak, this stream can produce up to 20 meteors per hour. The Delta Aquarid meteor shower takes its name from the star Delta Aquarii located in the constellation Aquarius as the meteors appear to radiate from a point near this star. The possible parent of the stream is the comet 96P/Machholz. The Delta Aquariids will be best visible in the Southern Hemisphere and tropical latitudes in the Northern Hemisphere.

August 12-13: The Perseid meteor shower

Probably one of the best meteor streams to watch — the Perseid meteor shower — peaks on August 12-13. On these dates, observers will have an opportunity to catch up to 60 meteors per hour, which will appear to originate from the constellation Perseus. The Perseids are active annually from July 17 to August 24 and are produced by the comet Swift-Tuttle. No doubt that the Perseid meteor shower will bring you an unforgettable experience — if you know where to look for it and the best time to view it. Shortly before the event, we'll give you some stargazing tips on how to catch as many meteors as possible!

Planets at Opposition

August 2: Saturn at opposition

Early August will be the best time to view Saturn and its rings because the gas giant will reach opposition on August 2. A planet is said to be at opposition when the Earth is placed between it and the Sun. Around opposition, the gas giant will pass its closest point to our planet and its face will be completely illuminated by the Sun — that's why Saturn will appear at its largest and brightest in the night sky. You will be able to enjoy its view and take photos of this amazing planet and its rings throughout the night.

August 20: Jupiter at opposition

On August 20, astronomy enthusiasts will have a chance to enjoy Jupiter at its best apparition: on this day, the largest planet in the Solar System will reach opposition and will appear brighter and bigger in the sky than at any other time of the year. Also, Jupiter's opposition is the best moment to observe its Galilean moons through binoculars or a telescope.

September 14: Neptune at opposition

Another planet to reach opposition this astronomical summer is Neptune. On September 14, the eighth and outermost planet from the Sun will be 180° from our star, while the Earth will pass between them. Even though the ice giant will reach the closest point to our planet and appear at its best, it won't be visible to the unaided eye. Use a pair of binoculars or a telescope to see the blue planet.

Mercury’s greatest elongations

July 5: Mercury at greatest western elongation

Early July is the best time to view Mercury at its favorable morning apparition. On July 5, the speedy little planet will reach its greatest western elongation, lying at a distance of 21.6 degrees from the Sun. Try to spot elusive Mercury low in the eastern part of the sky just before sunrise.

September 13: Mercury at greatest eastern elongation

September will give us one more chance to observe Mercury at its best. On September 13, the planet will reach its greatest eastern elongation of 26.8 degrees from the Sun. You'll see Mercury shining low in the western part of the sky after sunset. Mercury's eastern elongation is also known as the evening one as the little planet is visible during the evening. Vice versa, the western elongation is called the morning one because Mercury shines in the morning sky.

Full Moons

June 24: Super Strawberry Moon

The Strawberry Full Moon that falls on June 24 will be the first Full Moon to grace the sky of astronomical summer 2021. According to North American traditions, the June Full Moon marks the time to gather ripening fruit and the peak of the strawberry harvesting season, hence its name. Some sources consider it the last of three supermoons for 2021, although the author of the "Supermoon" term, Richard Nolle, didn't include it in the 21st Century Supermoon List. By the way, you can learn more curious facts about Supermoons and Micromoons with our infographic.

Supermoons & Micromoons
What is a Supermoon and a Micromoon? When to observe our natural satellite at its biggest and brightest? Take a look at this infographic to find it out!
See Infographic

August 22: Blue Moon

On August 22, the brilliant Blue Moon will adorn the sky! Actually, what is a Blue Moon? Surprisingly enough, this name has nothing to do with the Moon's color: it highlights the rarity of this phenomenon. There are two definitions of the Blue Moon: according to the monthly definition, it is the second Full Moon in a calendar month with two Full Moons; by the seasonal definition, it is the third Full Moon of the season with four Full Moons — that's the case of this August Full Moon. Don't miss your chance to witness this rare astronomical event!

Colors of the Moon
Test your knowledge of lunar hues! 🌕🌈Only 15% manage a perfect score in our Moon quiz. Dare to be one?
Take the quiz!

September 20: Harvest Moon

Summer of 2021 will end with the September equinox, which will occur on September 22. The closest Full Moon to this event is known as the Harvest Moon: this year, it will grace the sky on September 20. The bright light of the Harvest Moon traditionally helped farmers harvesting their crops to work into the night, hence the name.

Planetary Conjunctions

July 13: Conjunction of Venus and Mars

On the evening of July 13, view the spectacular conjunction of Venus and Mars. The brightest planet in the sky, Venus, will outshine Mars by about 200 times, so you'll probably need binoculars to spot the Red Planet. To see this astronomical duo, find an unobstructed horizon and look in the direction of sunset at dusk.

August 19: Conjunction of Mercury and Mars

Another stargazing event to see on August 19 is the conjunction of Mercury and Mars. This duo will be placed among the stars of the constellation Leo. However, Mercury and Mars will be challenging to see as they will be close to the setting Sun. Use a pair of binoculars and look for the planets at sunset.

What other stargazing events will occur this summer?

  • Shortly before the June Full Moon, Jupiter began its retrograde motion: the gas giant will resume its direct motion no earlier than mid-October.
  • Another curious celestial event to take place in late June is Mars' passage through the Beehive star cluster also known as Messier 44 in the constellation Cancer. Start watching for these beautiful sky objects after dusk on June 23.
  • In mid-July, New Yorkers will be more fortunate than others. Those located in the Big Apple will be able to witness Manhattanhenge on July 12-13! This amazing phenomenon occurs when the Sun aligns with the streets forming the main street grid of Manhattan on dates close to solstices. Manhattanhenge takes place four times a year: in December and January at sunrise and in May and July at sunset.
  • Also, starting in July, stargazers from the Northern Hemisphere can observe the Summer Triangle asterism at its finest. This prominent asterism consists of 3 brilliant stars: Deneb, Vega, and Altair. You'll see the Summer Triangle overhead around midnight in July and August. By the way, what is the difference between a constellation and an asterism? Find it out in our recent article!
  • September (as well as October) is perfect for observing the closest large galaxy to the Milky Way — the Andromeda Galaxy (also known as Messier 31) — from the Northern Hemisphere. Take your binoculars and watch the beautiful object overhead around midnight. Moreover, the Northern Lights season starts in September: these green lights are especially active around the September equinox.

These are the major astronomical events of summer 2021. If you enjoyed our stargazing highlights for the new season, share this article with your friends. Wishing you clear skies and happy stargazing!