Penumbral Lunar Eclipse
March 25, 2024

Here's the Moon on March 25, 2024, at 3:13 am EDT, the mid-point of a deep (about 96%) penumbral eclipse, but not quite deep enough to be a partial eclipse, where the lunar limb would enter the darker umbra of the earth's shadow as shown in the Sky & Telescope diagram below from this Bob King online article. Here's more from Time & Date and here's Fred Espenak's NASA datasheet.   This is a single raw frame taken under a clear sky from Maple Shade, NJ, with a Canon EOS RP DSLM camera and a Canon 400 mm f/5.6L telephoto lens on a fixed tripod. It was exposed 1/800 second at f/11, ISO 800 (the "Looney Eleven" rule-of-thumb for lunar exposure) and set to monochrome mode. Using Canon's Digital Photo Professional 4, contrast was enhanced and it was cropped to a 4:3 ratio from about 20% of the original frame dimensions for a field 1.0° wide x 0.75° high, then converted to this JPEG.   Visually, the darkening towards the bottom of the lunar disc was barely detectable with unaided eyes. Had I not known there was an eclipse in progress, it probably would have gone unnoticed.  With 15x56 binoculars, the darkening was slightly more apparent. The last penumbral eclipse I observed with some diligence was on July 5, 2020. It wasn't very deep and I saw no real effect as described farther down the page.

Penumbral Lunar Eclipse
July 5, 2020

 

The Earth's Moon entered the outer portion of the Earth's shadow, the penumbra, late on the evening of July 4, 2020, about 11:04 pm EDT, and reached maximum eclipse at 12:30 am on July 5, but only about a third of the Moon (at the top) was covered, so the eclipse was barely visible at best. Full Moon would occur at 12:44 am and the Moon would transit the local meridian at 1:06 am, 25° altitude (1:00 am is astronomical midnight during Daylight Time). Indeed, this image (with contrast increased), a binocular view and a view with unaided eyes all showed no real sign of the penumbra on the lunar disc to this observer. This corresponds with Fred Espenak's prediction in a Spaceweather article.   The image was captured on July 5, 2020, at 12:30 am EDT from my backyard in Maple Shade, NJ, using a Canon EOS RP mirrorless digital camera with a Canon 400 mm f/5.6L telephoto lens on a fixed tripod. It's a single raw monochrome frame exposed 1/800 second at f/11, ISO 800 (which coincidently corresponds to the "Looney Eleven" rule-of-thumb). Contrast was increased using Canon's Digital Photo Professional 4, then it was cropped to about a quarter of the original linear dimensions for field about 1.3° wide x 0.8° high and saved as a JPEG for this web page.

Joe Stieber
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