The Total Lunar Eclipse of Sunday, May 15<sup>th</sup>, 2022

The Total Lunar Eclipse of
Sunday, May 15th, 2022

The moon will rise during the first partial phase, followed by a fairly deep total eclipse.

May 15, 2022 lunar eclipse phases

Adapted from a diagram by NASA.  Note that, although the moon's orbital motion causes it to move to the lower left (east) relative to Earth's shadow, it (and the shadow) are moving to the upper right due to Earth's rotation.  Thus, for observers in Idaho, the moon moves higher in the sky relative to the local horizon throughout the eclipse.

Eclipse timeline (all times listed are in Mountain Daylight Time (GMT-6 hrs.), and rise/twilight times are given for Twin Falls, Idaho, USA):

  • 8:45 PM — Moonrise.  With the first partial phase (U1) having begun at 7:28 PM, the rising moon is already showing a dark "bite" missing from its lower left edge.  Centennial Observatory opens, weather permitting.  Views provided through small telescopes on the Stargazers' Deck until the moon is high enough for the 24" telescope (10:39 PM).
  • 8:53 PM — Sunset.
  • 9:29 PM — Total phase (U2) begins (second umbral contact).  The moon is completely immersed in Earth's umbra, taking on a red-orange, orange-brown, or darker color, depending on global atmospheric conditions.  Totality begins with the moon appearing darkest at the lower left and brightest at the upper right.
  • 10:13 PM — Greatest eclipse.  The moon reaches its maximum excursion into the umbral shadow, appearing at its darkest.   For this particular eclipse, the moon will be fairly deep in the umbral shadow, and so may appear quite dark.
  • 10:39 PM — Moon's altitude 15°.  Moon is high enough to view with the 24” telescope.
  • 10:53 PM — End of astronomical twilight.
  • 10:54 PM — Total phase (U3) ends (third umbral contact).  Just before this point, the moon appears darkest on top and brightest on the bottom.  As it emerges from Earth's umbra, a growing, bright sliver appears at lower left edge of the lunar disk.
  • 11:55 PM — Partial phase (U4) ends (fourth umbral contact).  The last, dark "bite" of shadow slips off the moon's upper right edge.  From this point on, the moon appears normal, except for an increasingly subtle darkening of its upper right edge from Earth's penumbral shadow.
  • 12:00 AM — Observatory closes.
  • 12:51 AM — Last penumbral phase ends (P4).  Well before this point, the moon appears completely normal to the eye, the penumbral shading being too subtle to detect.