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The ‘Hunter’s Moon’ over Philly is full Sunday, and will keep on giving this year

For all practical considerations we will be getting four early-rising full moons this October.

A commercial  airliner flies in the foreground the waxing "Super Moon" in July. This should be quite the holiday weekend for lunar connoisseurs.
A commercial airliner flies in the foreground the waxing "Super Moon" in July. This should be quite the holiday weekend for lunar connoisseurs.Read moreSTEVEN M. FALK / Staff Photographer

While the so-called Harvest Moon occurred in September, this year lunar connoisseurs in the region should be reaping quite a visual harvest with the October rendition of the full moon.

First — and perhaps foremost, given the gloom of the last week — those who forecast weather for a living promise the night skies really are going to be clear through the weekend into the workweek.

The moon will reach the instant of fullness at 4:54 p.m. Sunday, and is due to peak above the horizon in its distorted, oversize, amber glory at 6:39, just seven minutes after sunset. That means it will become an impressive, shadow-making night light while most people are still awake.

» READ MORE: Maybe we'll visit that moon some day

Along with the fact that it will be joined through the night by the jewel of Jupiter — still by far the brightest object not called the moon — for all practical considerations we will be getting four early-rising full moons, starting Saturday.

That’s all part of the monthly celestial ballet between the Earth and its only satellite.

Twilight zones

When visible the moon comes up later and later during its 28-day orbit about the Earth.

That’s related to the complex calculations regarding its position relative to our eastern horizon. One factor is the slightly elliptical lunar orbit. Its speed varies depending on its distance from the planet, moving faster when closer, and slower when farther, says Karen Masters, astrophysics professor at Haverford College.

The upshot is that moonrise times can vary tremendously, notes Connor Marti, with the Edelman Planetarium at Rowan University.

In April, around the time of the full moon, it was rising more than an hour later each calendar day.

Now, however, the moonrise time differences will be about as short as they have been all year.

» READ MORE: We had a great run of "super moons" this year

On Saturday night it came up at 6:15, right before sunset. It will first appear not long after sunset on Monday, at 7:03, and Tuesday, at 7:30.

While the moon will be truly full only for an instant, it will beam at a respectable 98.6% Saturday night; 98.9% on Monday, and 95.7% on Tuesday. That’s quite a harvest of moonlight for a holiday weekend. It will appear unusually large when it comes up.

Yes, that’s an optical illusion, says Masters, but that doesn’t make it any less spectacular.

About the ‘Hunter’s Moon’

The origin of label isn’t entirely clear, although it first appeared in the Oxford English Dictionary over 300 years ago, according to the Farmers’ Almanac.

The best guess is that it was related to the harvested fields being ideal for hunting during the well-lighted night.

The Indigenous peoples had an assortment of other names that were related to what they experienced in October, including the Falling Leaves Moon and the Migrating Moon, for the birds taking flight for their overwintering grounds.

Jupiter still rules

With its estimated 79 moons, Jupiter reached peak brightness when it made its closest approach to Earth in 59 years last month, and Earth, the sun, and the solar system’s biggest planet were directly aligned.

» READ MORE: Jupiter has made its closest approach, but it's still up there shining

It is ever so slowly pulling away, but it remains so bright that it can hold its own against the waxing moon. In fact, the two look as if they were made for each other.

Far brighter than any other star or planet, Jupiter will continue to dominate the night sky for at least the next few months, Marti says.

“It’s fun to watch each night,” he said.

Instant moon?

Jupiter ultimately will dim from our perspective, but the moon won’t, and these days ever more attention is shining upon it with NASA’s moon-exploration Artemis missions.

Artemis ultimately will provide clues about the moon’s origin, said Jacob Kegerreis, a researcher at NASA’s Ames Research Center. He was part of a team that concluded the moon might have been born in a matter of hours after an object the size of Mars smashed into the Earth billions of years ago.

With high-resolution simulations the team hypothesized that debris from the collision might have been launched into orbit, and the aftermath has been circling us ever since.

In short, that orb in the night sky that has so inspired the human imagination might hold powerful secrets about where we came from.