Five Moon-Occultable Things!

Hey, everyone! The deliciously named Full Worm Moon, so named because of all the worms that start to crawl through the muddy ground this time of year, will be in your skies this coming Sunday, March 12. With that and all the talk about the moon occulting Aldebaran last weekend, and occulting the sun last week, the moon’s had a busy week of blocking stuff. After all, what’s an eclipse if not an occultation that happens close enough for there to be a shadow?

The moon can occult a bunch of things as it orbits and moves across the sky. The moon’s orbit is inclined by about 5 degrees relative to the plane of Earth’s orbit, which we see as the ecliptic, the sun’s path across the sky. So anything within about 5 degrees above or below the ecliptic can be occulted by the moon at one time or another.

Here’s five things other than Aldebaran, the sun, and our solar system’s planets that can be occulted by the moon:

  1. Antares: The brightest star in the constellation Scorpius.
  2. The Pleiades: Messier 45, the spectacular naked-eye open star cluster in Taurus.
  3. Spica: The brightest star in the constellation Virgo.
  4. Regulus: The brightest star in the constellation Leo.
  5. Zubenelgenubi: The flamboyantly named brightest star in the constellation Libra.
Things that can be occulted by the moon (from Stellarium)
Things that can be occulted by the moon (from Stellarium)

Have a great weekend, everyone, and clear skies!


6 thoughts on “Five Moon-Occultable Things!

  1. More goodies for me to mention in my evening sky shows! Can i ask you a question? I just learned how to identify the Winter Triangle with our planetarium, I can’t actually pull up the lines of it, just identify its stars, because it’s not a true constellation (therefore not in my dropdown list). Am I right by saying the Winter Triangle is an asterism?

    Liked by 1 person

    1. Right! Exactly. There are 88 constellations that are formally recognized by astronomers. Asterisms, on the other hand, are not formally recognized groups of stars in any number of constellations. The Winter Triangle (what’s that, Betelgeuse, Procyon and Sirius, right?) is one of those asterisms. Asterisms can be kind of confusing because, for instance, what we see as Orion is actually the asterism, the group of stars, in Orion. The constellation Orion is much bigger. Constellations have defined borders are adjacent to one another, and, together, take up the whole sky, like states or countries are to continents. The Winter Triangle and Winter Circle are well-known but not formally recognized groups. Like you say, asterisms!
      Does that help?

      Please, no apologies for asking questions. I’m glad to answer. Good luck with your show!

      Liked by 1 person

      1. Ooo, I meant to say Winter Circle, I highlighted Sirius, Procyon, Pollux, Capella, Aldebaran and Betelgeuse.
        Thanks for answering my question! So helpful!

        Liked by 1 person

  2. I don’t doubt this at all, but my initial reaction was that Antares is too low in the sky and The Pleiades too high for the Moon to pass over them. Yet the Moon seems to flirt with Aldebaran almost every month.


    1. Yeah, I had the same thought at first when I got thinking about this and then doing my research. I remembered the Pleiades is close enough–I remember reading about them being being occulted some years ago. Antares is low around where I live, too, and but it gets much higher in the sky the farther south you go. I agree, though, it seems strange to think of it that way; their height in the sky doesn’t really matter. We’re in the middle of a long run of Aldebaran occultations, so it does happen all the time, at least these days.

      Liked by 1 person

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