Lunar eclipse visible in the Coachella Valley Thursday night

A near-total lunar eclipse is expected to be visible across the Coachella Valley late Thursday night and early Friday morning. The event, which will see the full moon turn a brownish-red as it is covered by the earth's shadow, will begin around 11:15 p.m. and end at approximately 2:25 a.m.

Lunar eclipses occur when the Earth moves in between the sun and the moon, blocking much of the sun's light from reaching what might otherwise be a bright full moon.

"The Earth casts a shadow pointing away from the sun," said Robert Victor, a retired astronomer and member of the Astronomical Society of the Desert. "The moon moves into that shadow tonight."

The result is a reddish-brown moon caused, according to Victor, by the refraction of light through Earth's atmosphere on its way to the moon. Victor noted that a tiny sliver of the moon's southern edge would not be covered in tonight's eclipse, resulting in a narrow edge of silvery-white during the event.

Lunar eclipses occur approximately once every six months. For obvious reasons, they are only visible from the nighttime side of the Earth, meaning that anyone on the daytime side of the planet would not see anything unusual during the events. 

Weather also plays a role, with cloud cover or other phenomenon frequently diminishing the visibility of the eclipses. Victor noted that the last lunar eclipse in the Coachella Valley six months prior was difficult to observe due to cloudy weather.

The National Weather Service predicts Thursday evenings' skies will be partly cloudy — a tentative improvement on the last eclipse's conditions, but no guarantee of a strong showing. Victor said he anticipates the moon might not be very visible during the early stages of the eclipse, but will likely become clearer towards the "deepest eclipse" around 1 a.m.

For those who miss Thursday's lunar eclipse, two similar events are anticipated in 2022. An early-evening lunar eclipse will occur on May 15 and another will take place in the early morning hours of Nov. 8, 2022.

"That will be a great event for families with young kids," Victor said of the May eclipse. "It will be much more viewer-friendly than the one this time — except for for the night owls."

James B. Cutchin covers business in the Coachella Valley. Reach him at james.cutchin@desertsun.com.