Super Blue Blood Moon

  • Posted on: 30 January 2018
  • By: Ron Liskey

There will be a special celestial event visible from western North America and Hawaii in the pre-dawn sky on Wednesday, January 31 (that is, the night of Tuesday, January 30): a total lunar eclipse (when the Moon goes into Earth's shadow) that is also a "blue moon" (the second full moon in a single calendar month) and also a "supermoon" (when the full moon is close to Earth in its elliptical orbit). This will be a "super blue blood moon"!

Here are the relevant times in California

  • Partial eclipse begins: 3:48 a.m. PST
  • Total eclipse begins: 4:52 a.m. PST
  • Mid-eclipse: 5:30 a.m. PST
  • Total eclipse ends: 6:08 a.m. PST
  • Partial eclipse ends: 7:11 a.m. PST
  • Sunrise in San Francisco: 7:14 a.m. PST
  • Prime time (total eclipse) will be 4:52-6:08 a.m. PST.

The Moon will be setting in the west, close to the horizon (especially near the end of totality), so make sure you don't have any buildings, mountains, trees, or other obstructions when looking west from your viewing location.

At 5:30 a.m. (mid-totality), for example, the Moon will be about 19 degrees above the western horizon (90 degrees is straight up, 0 degrees is the horizon) -- that's roughly the angle between your thumb and pinky finger as seen by your eyes when your arm is stretched out and your fingers are open wide. You can take a quick look (perhaps out of one of your windows, if it faces west and has a pretty clear horizon) and then go back to sleep, or stay up for a few hours and watch the entire progression, or anything in between (or even nothing, preferring to stay asleep). You decide!

For more information

The Moon doesn't appear completely dark during a total lunar eclipse because some sunlight goes through Earth's atmosphere and is bent (refracted) toward the Moon, and then it bounces off the Moon back toward us. But the Moon's color generally appears some shade of yellow, orange, or even red because the light that reaches it has been filtered by Earth's atmosphere, preferentially getting rid of the violet, blue, and green colors -- just as in the case of the setting or rising Sun, which looks some shade of yellow, orange, or red, depending on the amount of particular matter (such as smoke) in the atmosphere.

Note that during the partial phases, Earth's shadow on the Moon looks distinctly curved. This is *always* the case during a lunar eclipse, and it was one of the many pieces of evidence that the ancients used to conclude Earth is round, not flat.