The Four Supermoons of 2024

December 2024  :  Greg Shanos

On average the moon is 238,855 miles (384,400 km) from Earth. Since its orbit is elliptical, at its farthest point, known as apogee, the moon is 252,088 miles (405,696 km) distant. At its closest point, or perigee, the moon is 225,623 miles (363,105 km) away.

A supermoon refers to any full moon that occurs when the moon is within 90% of its closest approach to Earth. The supermoon is 7% larger and 14% brighter than a typical full moon. Another reference states that a supermoon can appear up to 14% larger and 30% brighter compared to a typical full moon.  I state both references for completeness. Either way, a supermoon is both larger and brighter than a typical full moon. 

A supermoon requires two key alignments to occur. The moon needs to be at its closest approach, or perigee, to the Earth in its orbit. The moon also needs to be at full phase, which happens every 29.5 days when the sun fully illuminates the moon. Therefore supermoons can only happen a few times a year because the moon's orbit changes orientation while the Earth orbits the sun – that is why we don't see a supermoon every month. Serendipitously, there will be four supermoons in a row this year on August 19th, September 17th, October 17th, and November 15th. 

I was fortunate enough to observe all four supermoons under good seeing conditions perfectly clear skies! As a treat, the September 17th supermoon occurred during a partial lunar eclipse which was maximum at 8.7% during totality. Below are my images of the supermoons. All were taken using A Meade 60mm 260mm f/4 refractor was tracking the moon on an inexpensive Orion EQ equatorially mounted tripod. A ZWO ASI 178MM monochrome camera with an Optolong UV-IR cut filter using Firecapture v2.7.14 to acquire the video and a MSI GF65 gaming computer. The SER video file was processed using Autostakkert 3.1.4 and Registax 6.1.0.8. Further sharpening and processing in Photoshop CS4. Image by Gregory T. Shanos Longboat Key, Sarasota, Florida.

The four supermoons of 2024 according to data from Fred Espenak's guide

Upper Left: The Sturgeon Blue Supermoon occurred at 2:26 p.m. EDT (18h 26m UT) on Monday, August 19, 2024, when the moon was 100% fully illuminated. However, it was daytime from my location and the moon had not yet risen. This image was taken on August 19, 2024 at 11:48pm local time or August 20, 2024 at 3h 48m UT when the moon was full at 99.7% phase and only 37°above the horizon. 

Upper Right: The Harvest Supermoon occurred during a partial solar eclipse! This image was taken two minutes after maximum eclipse (8.7%) on September 17, 2024 at 10:46pm local time or September 18, 2024 2h 46m UT. The eclipsed supermoon was only 38 degrees above the horizon.

Lower Left: The Hunters Supermoon occurred at 7:26 am EDT (11h 26m UT) on Thursday, October 17, 2024, when the moon was 100% fully illuminated. However, it was daytime from my location and the moon was setting. This was the largest supermoon of the year. This moon was 14% larger at 33.5 arc sec in diameter. This image was taken on October 17, 2024 at 10:33pm local time or October 18, 2024 at 2h 33m UT when the moon was full at 99.4% phase and only 41°above the horizon. 

Lower Right: The Beaver Supermoon occurred at 4:29 p.m. ET (21h 29m UT) on Friday, November 15, 2024, when the moon was 100% fully illuminated. However, it was daytime from my location and the moon had not yet risen. This image was taken on November 15, 2024 at 8:52 pm local time or November 16, 2024 at 1h 52m UT when the moon was full at 99.8% phase and only 40°above the horizon.

I was fortunate enough to observe all four supermoons under good seeing conditions perfectly clear skies! As a treat, the September 17th supermoon occurred during a partial lunar eclipse which was maximum at 8.7% during totality. All images were taken using a Meade 60mm 260mm f/4 refractor tracking the moon on an inexpensive Orion EQ equatorially mounted tripod. A ZWO ASI 178MM monochrome camera with an Optolong UV-IR cut filter using Firecapture v2.7.14 to acquire the video and a MSI GF65 gaming computer. The SER video file was processed using Autostakkert 3.1.4 and Registax 6.1.0.8. Further sharpening and processing in Photoshop CS4. All images by Gregory T. Shanos Longboat Key, Sarasota, Florida.