This supermoon will undergo a partial lunar eclipse, which occurs when the Earth is positioned between the moon and the sun, casting the Earth's shadow on the surface of the moon, dimming it.

"I think that lunar eclipses are the more interesting celestial phenomena. A supermoon is a variety of a monthly full moon that appears slightly bigger in the night sky," said Jonathan Kemp, with Wellesley College's Whitin Observatory. "However, a partial eclipse has both an irregularity in timing and observability as well as a uniqueness of how it evolves and appears to an observer over the course of the event."

The full moon, or harvest moon, will officially appear at 10:35 p.m. EDT, with the peak of the eclipse happening minutes later, according to NASA.

You might want to catch this cosmic double-header while it lasts. The next supermoon-lunar eclipse combo doesn't take place until Oct. 8, 2033.

This is the first of three supermoons this year. The next one will take place on Oct. 17.

This go-around, the supermoon will last for roughly three days, through Thursday morning. The moon will reach perigee -- its closest point in its elliptical orbit -- at 9 a.m. EDT on Wednesday when it's 222,007 miles away.

"At its closest point, the full moon can appear up to 14 percent bigger and 30 percent brighter," Kemp said.

A supermoon does have an added effect on Earth: "Because the moon is in its closest approach to Earth, it can cause higher tides than usual," according to NASA.

The best time to view the moon partially eclipsed will be from 10:12 p.m. to 11:16 p.m., EDT.

Francine Jackson, an astronomer with Brown University's Ladd Observatory in Providence, R.I., said the moon will begin entering the Earth's outer shadow, the penumbra, at 8:41 p.m.

"The slight dimming of the moon will be difficult to notice until the top edge of the moon starts entering the full or primary shadow, the umbra, at 10:13 p.m. (EDT)," according to NASA. The eclipse will peak at 10:44 p.m. with only the top 8 percent of the moon plunged into darkness due to the shadow. The moon will then finish exiting the full shadow by 11:16 p.m.

"Since this partial eclipse only involves about 8.5% of the moon's diameter entering the Earth's shadow, Boston observers should look closely at the edge of the lunar disk to see this partial eclipse," said Jonathan Kemp, with Wellesley College's Whitin Observatory.

Experts said no binoculars are needed to view the eclipse as long as the weather cooperates.

So will the clouds interfere Tuesday night? Globe meteorologist Ken Mahan said your chances of catching both spectacles are best the farther north you are. Northern New England should see partly clear skies while partly to mostly cloudy skies are forecast for Southern New England.

While partial lunar eclipses happen at least twice a year, Kemp said, total lunar eclipses, in which the sun, Earth and moon are precisely aligned and the sunlight is completely blocked from reaching the moon, are quite rare. The next full one is next March, so stay tuned.

And if anyone wants to stay awake after tomorrow's eclipse, Jackson said there's an added bonus: the Neptune occultation.