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August 2023 Astronomy Events

August 2023 Astronomy Events

AstroTelescopium Team |

Late-summer stargazing in August 2023 begins with a bright Sturgeon supermoon on the first day of the month. A week later, on the 9th, Mercury reaches its widest separation from the Sun providing an observable placement for our closest neighbor. This is followed by asteroid Hygiea at opposition and the peak of one of the best meteor showers of the year (Perseid).  In the middle of the month, two globular clusters (M15 and M2) are well placed in the night sky. Finally, August ends with Saturn reaching opposition on the 27th and a second full moon that is referred to as the Blue moon. This occurs on the 30th.

(Looking to review last month's astronomy events? View July 2023)

Our highlighted list of astronomy events for August serves as your reference for key celestial sights to expect and to plan for.


8 Astronomical Events in August 2023:

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.


Before we get started, let's briefly define a few technical terms used in this article:

Magnitude - Magnitude is simply the measure of an object's brightness. The lower the number the brighter the object. Conversely, the higher the number the fainter the object. For example, a magnitude -7.2 object is brighter than a magnitude +3.6 object. Without optical assistance, the naked eye can see a celestial object as dim as roughly magnitude +6.0.

Right Ascension - Right ascension is the celestial equivalent of geographic longitude. It is measured from the Sun's position during March Equinox at 00h00m00s (h=hours, m=minutes, s=seconds). This measurement increases towards the east until it completes a full circle at 24h00m00s.

Declination - Declination is the celestial equivalent of geographic latitude. It is measured northward or southward of the celestial equator as degrees (°), minutes(') and seconds ("). For example, the celestial equator has a declination of 0°0'0", the north celestial pole has a declination of +90°0'0" and the south celestial pole has a declination of -90°0'0".

AU (astronomical unit) - AU is a unit of length that measures the distance from the Earth to the Sun.



Astronomy events to mark on your August 2023 calendar:


August 1st - Full Moon | Sturgeon Moon

Full Moon

On Tuesday, August 1st, the Moon will reach peak illumination in its 29.5 day lunar cycle. This astronomical event occurs each time the Moon's ecliptic longitude appears 180° away from the Sun's ecliptic longitude.

According to the Farmers' Almanac, in Native American cultures the Full Moon that occurs at this time during August is referred to as the Sturgeon Moon. The name is derived from the giant sturgeon (a type of fish) of the Great Lakes and Lake Champlain which were most readily caught during this part of summer.

The Full Sturgeon Moon will appear positioned in the Capricornus constellation at right ascension 20h51m00s and a declination of 22°45'S. Its angular size will be 33'24".


August 9th - Mercury at greatest eastern elongation


Mercury will appear at its widest separation from the Sun on Wednesday, August 9th. The planet will be positioned 27° east of the Sun shining at magnitude +0.3.

These wide separation moments are referred to as its greatest eastern elongation and occur approximately every 3-4 months.

During Mercury's moment of widest separation, the planet will be positioned in the Leo constellation at right ascension 10h58m30s and a declination of 4°46'N.

Due to Mercury's close proximity to the Sun, it is often difficult to safely observe this planet. Accidentally looking directly at the Sun could be extremely damaging to your eyes. Additionally, because the Sun's glare outshines any celestial object in close proximity to it, that object is hard to view.

For stargazers, the exact dates of Mercury's greatest eastern elongation and its greatest western elongation are significant moments. They provide an opportunity for more optimal observations of the closest planet to the Sun.


August 10th - Asteroid 10 Hygiea at opposition


Asteroid 10 Hygiea will be at opposition and reach its highest point in the sky at about midnight local time on Thursday, August 10th. When a celestial object is "at opposition", this refers to its 180° position opposite to the Sun.

On this day, the asteroid will appear brightest in the night sky due to its closest approach to Earth, within 2.039 AU of us.

Shining at a magnitude of +9.7, a moderate sized aperture telescope will be required in order for you to adequately observe.

Asteroid 10 Hygiea will be positioned in the Aquarius constellation at right ascension 21h14m40s and a declination of 12°35'S.

Hygiea was discovered by astronomer Annibale de Gasparis on April 12, 1849, in Naples, Italy.


August 13th - Perseid meteor shower peak


The Perseid meteor shower is active from July 14th to September 1st. It reaches its peak on Sunday, August 13th. Its radiant point, the area from which the shower appears to emanate, is positioned in the Perseus constellation around right ascension 03h10m and declination 57°N.

According to the American Meteor Society, the meteor shower's ZHR will be approximately 100 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 responsible for creating the Perseid shower is comet 109P/Swift-Tuttle.

Tips for viewing meteor showers:

  • Do not direct your gaze solely at 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.
  • Position 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 in which you can recline 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.


August 14th - M15 is well placed

Messier 15

The globular cluster Messier 15 (M15) will reach its highest point in the sky on Monday, August 14th at about midnight local time.

Shining at magnitude +6.2, M15 will be best observed with a pair of binoculars or at minimum a small aperture telescope.

M15, also referred to as NGC 7078, will be positioned in the Pegasus constellation at right ascension 21h29m50s and a declination of 12°10'N.

French astronomer Jean-Dominique Maraldi discovered M15 in 1746. It was later included in Charles Messier's catalog in 1764. M15 is approximately 35,700 light-years from Earth and is estimated to be 12.5 billion years old. 


August 15th - M2 is well placed

Messier 2

One of the largest known globular clusters, Messier 2 (M2), will reach its highest point in the sky on Tuesday, August 15th at about midnight local time.

Shining at a faint +6.6, a pair of binoculars or a small aperture telescope will be needed to observe this celestial object.

M2, also known as NGC 7089, will be positioned in the Aquarius constellation at right ascension 21h33m20s and a declination of 0°49'S.

Similar to M15, Jean-Dominique Maraldi discovered M2 in 1746. The globular cluster is approximately 55,000 light-years from Earth and contains about 150,000 stars.


August 27 - Saturn at opposition


Saturn will be at opposition and will reach its highest point in the sky at about midnight local time on Sunday, August 27th. When a celestial object is "at opposition", this refers to its 180° position opposite to the Sun.

At this time, Saturn will appear brightest in the night sky due to its closest approach to Earth within 8.76 AU of us.

Shining at magnitude +0.4, the planet can be seen with the naked eye. However, a pair of binoculars or, at minimum, a small aperture telescope can enhance your observation.

Saturn will be positioned in the Aquarius constellation at right ascension 22h24m10s and a declination of 11°52'S.


August 30th - Blue Moon

Full Moon

On the last day of August, the 30th, a second full Moon occurs. Whenever two full Moons occur in the same month, it is referred to as a Blue Moon. This rare Blue moon in August will not happen again until August of 2032.

The Blue Moon will appear positioned in the Aquarius constellation at right ascension 20h41m00s and a declination of 12°27'S. Its angular size will be 33'25".



    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.

    Feel free to browse our telescope collection or browse our binoculars.

    If you are unsure where to begin, you may read our blog post How To Choose The Right Telescope or How To Choose The Right Binoculars for additional guidance.


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