Rare moon phenomenon not seen since 2009 happens Wednesday above Boise. What to know
Boise residents will be able to see a rare phenomenon high in the sky on Wednesday night — a super blue moon. Experts expect it to be the largest and brightest moon of the year.
A blue moon is when a full moon occurs for the second time within a calendar month; a sturgeon supermoon kicked off August on August 1. Meanwhile, a supermoon occurs when either a full or new moon occurs when the moon is 90% — at least 223,694 miles — or greater toward its closest approach to Earth, according to Time and Date.
The last time these two phenomena occurred at the same time was December 2009, according to Time and Date, and the next time it’ll happen will be August 2032.
Wednesday night’s super blue moon will reach its maximum size at 7:36 p.m. Boise local time on Wednesday, according to Space.com. However, the minimal difference between the moon’s size at sunrise and sunset means that the moon will look extra large throughout the evening.
Similar to the sturgeon supermoon earlier this month, Wednesday night’s super blue moon will appear 10 to 11% larger than the average full moon.
The National Weather Service forecasts “clear skies” on Wednesday evening for Boise, making for easy viewing in the Treasure Valley.
The largest and brightest moon of the year
The closest point to which the moon approaches Earth is called the perigee, but it’ll occur when Idahoans won’t be able to see the moon at around 10 a.m. on Wednesday.
But as mentioned above, the visual difference of size in the moon being at its absolute closest point and about 9 hours later when it reaches full moon status and can be seen in Idaho is minimal.
Space.com says the moon will look largest when rising near the horizon, describing the phenomenon as the “moon illusion.”
“For reasons not fully understood by astronomers or psychologists, a low-hanging moon looks incredibly large when hovering near to trees, buildings and other foreground objects,” Space.com writes. “The fact that the moon will be much closer than usual on Wednesday will only serve to amplify this strange effect.”
While observing Wednesday night’s super blue moon, NASA notes that Saturn will be visible not far from the moon’s location in the sky. Saturn is also approaching its closest point to Earth of the year and will appear brightly in the sky toward the moon’s upper right.
More full moons in 2023
Here’s when to see more full moons in 2023, with information from Space.com:
Sept. 29: Harvest supermoon
Oct. 28: Hunter’s moon
Nov. 27: Beaver moon
Dec. 26: Cold moon
This story was originally published August 29, 2023 at 4:00 AM.
