Welcome to the second in our four part series detailing the major events of 2021’s astronomical calendar. This guide will help you to set your stargazing itinerary, providing a detailed listing of what each month’s sky has to offer. We began in March of 2021, when astronomical spring is ushered in with the Vernal Equinox on March 20th. Now, with the Estival Solstice, we will continue to follow the celestial rotation into summer.
This guide aims to provide you with precise dates that allow for easiest viewings of celestial objects from the vantage of North America, including the stages of the Moon, the planets, meteor showers, and the best times to view a number of highly sought after deep sky objects. For further details to help in locating these objects with their specific longitudes, there are a number of star-finder resources online that we suggest you view in preparation for viewing. Get your personal calendar ready so that you can plan out your amateur astronomy schedule for summer.
JUNE
The Estival Solstice
On June 20th, astronomical summer will begin with the June Solstice, named after the Roman sun god Sol, as the June Solstice is the longest day of the year in the Northern Hemisphere. We will experience over fifteen hours of daylight, as the earth’s northern pole will be pointed at the sun.
The Moon: Strawberry Moon
The Full Moon on June 24th will appear as what’s known as a Supermoon, when the Moon’s Full Moon phase occurs at the same time as the closest point in its orbit around Earth. The Supermoon is when the Moon will seem its largest and brightest in the night sky, appearing 7% larger than average. This particular Supermoon is also known as the Strawberry Moon, as it notified the Algonquin tribes that wild strawberries we ripened and ready to gather
M7
Also known as the Ptolemy Cluster, M7 peaks in height on the horizon on June 21st. First discovered by Ptolemy in 130AD, this open cluster is one of the first recorded star clusters and can be found in the constellation of Scorpius. Unfortunately, it can only be seen from the southernmost parts of the continent.
NGC 6530
Existing within The Lagoon Nebula, or M6530, NGC 6530 is an open star cluster that peaks in height on the horizon on June 24th. It can be located in the constellation of Sagittarius.
Saturn
Saturn will come into conjunction with the Moon on June 27th, both objects appearing within the constellation of Capricornus.
June Bootids Meteor Shower
Occurring between the dates of June 22nd to July 2nd, and peaking on June 27th, the June Bootids Meteor Shower radiates out of the constellation Bootes. Created by the shed of Comet Pons–Winnecke, the June Bootes Meteor Shower is one of the most unpredictable showers, sometimes very weak, and sometimes experiencing an outburst of activity, but always with some of the slowest moving meteors seen.
Jupiter
Jupiter will come into conjunction with the Moon on June 28th, both objects appearing within the constellation of Aquarius.
NGC 6633
Also known as the Captain Hook Cluster for its unique shape—or as the Tweedledum Cluster when paired with IC 4756, known as Tweedledee—NGC 6633 is an open cluster that peaks in height on the horizon on June 29th. It can be located in the constellation of Ophiuchus.
JULY
The Moon: Buck Moon
On July 1st, the Moon will appear at its Last Quarter, when the lunar terminator reveals the best time to view and photograph the left half of the visible Moon. July 10th sees the birth of the New Moon, when the cycle of the Moon’s phases begins anew. This is the best time to view and photograph the night sky, as the Moon’s illumination is at its lowest, granting the clearest views of the spiraling arms of the Milky Way. On July 17th, the Moon will be at First Quarter, revealing the right half of the visible Moon. The Full Moon on May 26th will appear as what’s known as the Buck Moon, named so because a buck’s antlers are in full growth during this time of the year. For a second time this month, on July 31st, the Moon will once again appear at its Last Quarter.
M22
Also known as the Great Sagittarius Cluster, M22 is an elliptical globular star cluster that will peak in height on the horizon on July 2nd. It is one of the brightest globular clusters in the night sky, and is located in the constellation of Sagittarius, and is one of only four known globular clusters that reside within our own Milky Way Galaxy.
IC 4756
Also known as the Secret Garden Cluster—or as the Tweedledee Cluster when paired with NGC 6633, known as Tweedledum—IC 4756 is an open cluster that peaks in height on the horizon on July 2nd. It can be located in the constellation of Serpens.
Comet 15P/Finlay
Reaching its brightest point on July 8th, Comet 15P/Finlay will be visible, moving from the constellation of Aries into Taurus for the remainder of July. It will reach perihelion, or its furthest point from the Sun, on July 14th.
Mercury
Mercury reaches dichotomy on July 9th, where it will be lit similar to the way the Moon is during its Quarter Phases, and will also reach its highest point in the morning sky. This occurs just after its reaches its point of greatest western elongation from the Sun on July 5th.
Venus
Venus will come into conjunction with the Moon on July 12th, both objects appearing within the constellation of Leo.
M55
Also known as the Summer Rose Star, M55 is a globular star cluster that will peak in height on the horizon on July 18th. It can be located in the constellation of Sagittarius, but unfortunately will only be visible to the southernmost portions of North America.
Pluto
Pluto will reach opposition on July 18th, reaching its highest point on the horizon in the constellation of Sagittarius. This will be one of the best times to photograph the dwarf planet, once considered the ninth planet in our solar system.
Asteroid 6 Hebe
Asteroid 6 Hebe will reach opposition on July 18th, and can be visible in the constellation of Aquila. Asteroid 6 Hebe is the fifth brightest object in the asteroid belt.
Saturn
Saturn will come into conjunction with the Moon on July 24th, both objects appearing within the constellation of Capricornus.
Jupiter
Jupiter will come into conjunction with the Moon on July 25th, both objects appearing within the constellation of Aquarius.
Piscis Austrinid Meteor Shower
Occurring between the dates of July 15th to August 10th, and peaking on July 28th, the Piscis Austrinid Meteor Shower radiates out of the constellation Piscis Austrinus. It is not known what object is responsible for the shed of the meteors, and this particular meteor shower is quite faint.
Southern Delta Aquariid Meteor Shower
Occurring between the dates of July 12th to August 23rd, and peaking on July 30th, the Southern Delta Aquariid Meteor Shower radiates out of the constellation Aquarius. It is speculated that the shower was created by the shed of Comet 96P Machholz.
Alpha Capricornid Meteor Shower
Occurring between the dates of July 3rd to August 15th, and peaking on July 30th, the Alpha Capricornid Meteor Shower radiates out of the constellation of Capricornus. The shower was created by the shed of Comet 169/NEAT, which lost almost half its mass nearly 5,000 years ago, creating the meteors that produce this shower. The Earth’s rotation will collide with the largest portion of the debris in the 24th Century, creating a meteor shower larger than any seen today.
Asteroid 12 Victoria
Asteroid 12 Victoria will reach opposition on July 30th, and can be visible in the constellation of Aquila.
AUGUST
The Moon: Sturgeon Moon
August 8th sees the birth of the New Moon, when the cycle of the Moon’s phases begins anew. This is the best time to view and photograph the night sky, as the Moon’s illumination is at its lowest, granting the clearest views of the spiraling arms of the Milky Way. On August 16th, the Moon will be at First Quarter, revealing the right half of the visible Moon. The Full Moon on August 22nd will appear as what’s known at the Sturgeon Moon, called so by the Algonquin tribes as this is the time of year when fish populations would peak. The Moon will appear in Last Quarter on August 30th, when the lunar terminator reveals the best time to view and photograph the left half of the visible Moon.
Saturn
Saturn will reach opposition on August 2nd, appearing within the constellation of Capricornus. This is the best time to photograph the ringed planet. If you happen to catch Saturn during the precise moment of its opposition, timed at 06:01 UTC, you will witness what is known as the Seeliger Effect, where the ice particles that compose Saturn’s rings will be brightly illuminated. Saturn will also come into conjunction with the Moon on August 20th, both objects appearing within the constellation of Capricornus.
Venus
Venus will come into conjunction with the Moon on August 11th, both objects appearing within the constellation of Virgo.
Perseid Meteor Shower
Occurring between the dates of July 17th to August 24th, and peaking on August 12th, the Perseid Meteor Shower radiates out of the constellation of Perseus. The shower was created by the shed of Comet Swift–Tuttle, and is one of the strongest meteor showers the Earth sees each year.
Asteroid 349 Dembowska
Asteroid 349 Dembowska will reach opposition on August 12th, and can be visible in the constellation of Piscis Austrinus. 49 Dembowska is one of the largest asteroids in the main Asteroid Belt.
M15
Also known as the Great Pegasus Cluster, M15 is a globular star cluster that will peak in height on the horizon on August 15th. It can be located in the constellation Pegasus, and is one of the oldest and densest globular clusters known. M15 also hosts an inordinate amount of pulsars and variable stars.
M2
M2 is a globular star cluster that will peak in height on the horizon on August 16th. It can be located in the constellation Aquarius. M2 was the first object added to the Messier Catalog, and is one of the largest known globular clusters.
Kappa Cygnid Meteor Shower
Occurring between the dates of August 3rd to August 25th, and peaking on August 18th, the Kappa Cygnid Meteor Shower radiates out from between the constellations of Cygnus and Draco. It is not known what object is responsible for the shed of the meteors, although asteroids 2002 LV and 2001 MG1 are recent suspects.
Asteroid 43 Ariadne
Asteroid 43 Ariadne will reach opposition on August 19th, and can be visible in the constellation of Aquarius. It is the second-largest member of the Flora asteroid family, which has over 13,000 known members.
Jupiter
Jupiter will reach opposition on August 19th, appearing within the constellation of Capricornus. This is the best time to photograph the gas giant. Jupiter will also come into conjunction with the Moon on August 22nd, both objects appearing within the constellation of Capricornus.
Asteroid 89 Julia
Asteroid 89 Julia will reach opposition on August 24th, reaching its highest point on the horizon in the constellation of Virgo. Considered a minor planet, 89 Julia birthed the Julia family of asteroids after an impact 30 to 120 million years ago.
SEPTEMBER
The Moon: Harvest Moon
September 7th sees the birth of the New Moon, when the cycle of the Moon’s phases begins anew. This is the best time to view and photograph the night sky, as the Moon’s illumination is at its lowest, granting the clearest views of the spiraling arms of the Milky Way. On September 13th, the Moon will be at First Quarter, revealing the right half of the visible Moon. The Full Moon on September 20th will appear as what’s known at the Harvest Moon, as it typically coincides with harvest festivals. The Harvest Moon is the only Moon name designation that changes months, occurring in October once every three years, as the name is relevant to whatever Full Moon occurs closest to the September Equinox. Other years, September’s Full Moon is known as the Corn Moon. The Moon will appear in Last Quarter on September 28th, when the lunar terminator reveals the best time to view and photograph the left half of the visible Moon.
Aurigid Meteor Shower
Occurring between the dates of August 28th to September 5th, and peaking on September 1st, the Aurigid Meteor Shower radiates out from the constellation Auriga. The shower was created by the shed of Comet Kiess.
Mercury
Mercury will reach its highest point above the horizon on September 3rd. This makes it the best time to observe and photograph the first planet from the Sun. This occurs just over a week before its point of greatest eastern elongation from the Sun on September 13th, and two weeks before Mercury reaches dichotomy, where it will be lit similar to the way the Moon is during its Quarter Phases, on September 17th.
September Epsilon Perseid Meteor Shower
Occurring between the dates of September 5th to September 21st, and peaking on September 9th, the September Epsilon Perseid Meteor Shower radiates out from the constellation Perseus. It is not known what object is responsible for the shed of the meteors.
Venus
Venus will come into conjunction with the Moon on September 9th, both objects appearing within the constellation of Virgo.
Asteroid 2 Pallas
Asteroid 2 Pallas will reach opposition on September 11th, reaching its highest point on the horizon in the constellation of Pisces. It is the third-largest asteroid in the Solar System, and was the second asteroid to be discovered. It is speculated that Asteroid 2 Pallas is a remnant protoplanet, and in fact, when it was first discovered in 1802, it was thought to be a planet.
Neptune
Neptune will reach opposition on September 14th, reaching its highest point on the horizon in the constellation of Aquarius. This will be one of the best times to photograph the eighth, and now considered final, planet in our solar system.
Saturn
Saturn will come into conjunction with the Moon on September 16th, both objects appearing within the constellation of Capricornus.
Jupiter
Jupiter will come into conjunction with the Moon on September 18th, both objects appearing within the constellation of Capricornus.
