2019: May 11-13: Moon and Leo in Evening Sky


Leo, the Lion, stands high in the southwest as the sky darkens in early to mid-May.  The shape is fairly easy to locate.  Six stars resemble a backwards question mark, also known as “The Sickle” for the farm implement.  A triangle trails farther east.  Regulus is the bottom star of the question mark and represents the lion’s heart.  Denebola marks the lion’s tail.  The celestial lion is majestically facing westward as we view its profile.  The moon moves through the region May 11-13, 2019.  Here’s what to look for:

  • May 11: The moon reaches its First Quarter phase at 8:12 p.m. CDT. One hour after sunset, the moon, 7.1 days past its New Phase and 50% illuminated, is high in the southwest, 8.9° to the right of Regulus.

The angular degree measurement is used in astronomy to determine the separations and sizes of objects.  Because objects have various actual sizes and distances from Earth, the degree is the way for us to communicate apparent sizes and apparent separations.  The full moon has an apparent diameter of about 1/2°.  The charts we use typically exaggerate the size of the moon, so the chart cannot be used for a scale with the moon.  The distance from Regulus to Denebola is about 24°.

  • May 12: One hour after sunset, the moon (8.1d, 62%) is 6.2° to the upper left of Regulus.
  • May 13: The moon is closest to Earth at 4:53 p.m. CDT. An hour after sunset, the moon (9.1d, 73%), nearly 60° up in the south, is 8.5° to the lower right of Denebola– the tail of Leo.
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