By all reports, the faint partial penumbral lunar eclipse of July 4-5, 2020, was barely discernible (if that), even by experienced observers. At maximum eclipse, only about a third of the moon was covered by Earth’s faint, outer penumbral shadow. And – for most of us – that’s not enough to make the eclipse visible, according to experts.
During past lunar eclipses, I have made a concerted effort to determine when I can first see the subtle shading of Earth’s penumbral shadow on the moon (using unaided eye and binoculars). I have consistently found the penumbral shading is only detectable when at least 2/3 of the moon lies within the penumbral shadow.
Since the moon will only pass 1/3 of the way into the penumbral shadow during the July 4/5 lunar eclipse, it will not be visible to the unaided eye. But digital photography can reveal the subtle shading if the contrast of the image is greatly increased.
On the other hand, it’s been my experience that people’s powers of observation vary greatly. Some people have exceptional eyesight. Some have a really remarkable ability to notice subtle details. If that’s you, and you noticed Earth’s shadow on the moon during this eclipse, let us know in the comments below!
Bottom line: Even experienced observers say they couldn’t discern the Earth’s shadow on the moon during the partial penumbral eclipse of July 4-5, 2020. Did you see it? Do your photos show it? Let us know in the comments below, or post at EarthSky Community Photos.
Deborah Byrd created the EarthSky radio series in 1991 and founded EarthSky.org in 1994. Today, she serves as Editor-in-Chief of this website. She has won a galaxy of awards from the broadcasting and science communities, including having an asteroid named 3505 Byrd in her honor. A science communicator and educator since 1976, Byrd believes in science as a force for good in the world and a vital tool for the 21st century. "Being an EarthSky editor is like hosting a big global party for cool nature-lovers," she says.