July 2023 kicks off with great placements of star clusters Messier 22 (M22) and IC 4756. Shortly thereafter, the Full Buck Moon shines at peak illumination positioned in the Sagittarius constellation. Just before we end the month with displays of the Southern δ-Aquariid meteor shower peak, Asteroid 15 Eunomia and Pluto both reach opposition placements to the Sun allowing them to appear their brightest in the night sky.
(Looking to review last month's astronomy events? View June 2023)
Our highlighted list of astronomy events for July serves as your reference for key celestial sights to expect and to plan for.
6 Astronomical Events in July 2023:
- M22 is well placed - 7/1
- IC 4756 is well placed - 7/2
- Full Buck Moon - 7/3
- Asteroid 15 Eunomia at opposition - 7/7
- Pluto at opposition - 7/22
- Southern δ-Aquariid meteor shower peak - 7/30
For easy navigation, click on a specific event listed above to go directly to that section of the article. Below, we will explore each of these events in greater detail.
Astronomy events to mark on your July 2023 calendar:
July 1st - M22 is well placed
One of the brightest visible globular star clusters, Messier 22 (M22), will reach its highest point in the sky on Saturday, July 1st around midnight local time.
Shining at magnitude +5.2, M22 will be best observed with a pair of binoculars or a small telescope.
M22, also known as NGC 6656, will be positioned in the Sagittarius constellation at right ascension 18h36m20s and at a declination of 23°54'S.
German astronomer Abraham Ihle first discovered M22 on August 26, 1665. It was later included in Charles Messier's catalog in 1764. M22 is approximately 10,600 light-years away from Earth and is one of only four globulars known to contain a planetary nebula.
July 2nd - IC 4756 is well placed
IC 4756, the large open star cluster known as the Tweedledee Cluster, will reach its highest point in the sky on Sunday, July 2nd around midnight local time.
At magnitude +4.6, IC 4756 will be positioned in the Serpens Cauda constellation at right ascension 18h38m50s and at a declination of 5°27'N.
July 3rd - Full Moon | Buck Moon
The Moon will reach peak illumination in its 29.5 day lunar cycle on Monday, July 3rd. This event occurs whenever the Moon's ecliptic longitude appears 180° away from the Sun's ecliptic longitude, as observed from Earth.
According to the Farmers' Almanac, in Native American cultures the Full Moon that occurs in July is referred to as the Buck Moon. The name is derived from the antlers of male deer (bucks) being in full-growth mode at this time. Bucks shed and regrow their antlers each year, producing a larger and more impressive set as the years go by.
The Full Buck Moon will appear positioned in the Sagittarius constellation at right ascension 18h49m30s and a declination of 27°41'S. Its angular size will be 32'59".
During this time, the Moon rises above the eastern horizon at about sunset and sets below the western horizon at about sunrise the following day.
July 7th - Asteroid 15 Eunomia at opposition
Asteroid 15 Eunomia will be at opposition and reach its highest point in the sky around midnight local time on Friday, July 7th. When a celestial object is "at opposition", this refers to its 180° position opposite to the Sun.
On this day, the asteroid also appears brightest in the night sky due to its closest approach to Earth, within 1.679 AU of us.
At a magnitude of just +8.8, a moderate sized aperture telescope will be needed to get a good view of this celestial object.
Asteroid 15 Eunomia will be positioned in the Sagittarius constellation at right ascension 19h06m40s and a declination of 25°09'S.
Eunomia was discovered by Annibale de Gasparis on July 29, 1851.
July 22nd - Pluto at opposition
Pluto, formally designated "134340 Pluto", will be at opposition and reach its highest point in the sky around midnight local time on Saturday, July 22nd. When a celestial object is "at opposition", this refers to its 180° position opposite to the Sun.
On this day, the dwarf planet also appears brightest in the night sky due to its closest approach to Earth, within 33.80 AU of us.
At a magnitude of just +14.9, a moderate to large sized aperture telescope will be required to observe this celestial object.
134340 Pluto will be positioned in the Capricornus constellation at right ascension 20h07m30s and a declination of 22°57'S.
Pluto was discovered in 1930 and in 2006, the International Astronomical Union (IAU) formally redefined the term planet to exclude dwarf planets such as Pluto.
July 30th - Southern δ-Aquariid meteor shower peak
The Southern δ-Aquariid meteor shower is active from July 18th to August 21st, and reaches its peak on Sunday, June 30th. Its radiant point, the area from which the shower appears to emanate, is positioned in the Aquarius constellation around right ascension 22h40m and declination 16°S.
According to the American Meteor Society, the meteor shower's ZHR will be around 25 meteors per hour. ZHR is an abbreviation for Zenithal Hourly Rate and is defined as the hourly rate a meteor shower produces with a clear, dark sky, with the radiant at the zenith (highest point directly above the observer).
The parent body suspected to be responsible for creating the Southern δ-Aquariid shower is comet 96P/Machholz.
A few tips for viewing meteor showers:
- Do not direct your gaze solely towards the radiant point. The closer a meteor is in proximity to its radiant point, the more difficult it is to see because of its shorter trail.
- Place yourself in a dark, secluded location away from light pollution and bright city lights.
- Allow for up to 30 minutes for your eyes to properly adjust to the dark environment.
- Make sure to dress appropriately for the weather.
- Bring a comfortable lawn chair to recline in or a blanket to lie back on.
- Try to observe as wide an area of the sky as possible. The broader your view of the sky, the greater the chance of catching a glimpse of a meteor whizzing by.
Plan your observations
Now that you have a better idea of the celestial events occurring in the night sky this month, make sure to plan for your observation sessions. Some of the events discussed above can be seen without any special optical equipment. However, a quality pair of binoculars or a premium telescope will significantly enhance your viewing experience.
If you're in the market for purchasing or upgrading your astronomy gear, we have a curated selection of binoculars, telescopes and accessories from which to choose. Our online store offers high quality optics from industry-leading brands at value prices to help you explore the world above.