Monday, May 16, 2022

AIR day 8 - item 2

The following is a blog post from the Astronomer-In-Residence (AIR) web site, reproduced here. Text and images used with permission.

Day 8 blog entry.

Monday 16 May 2022: Lunar Eclipse Cycles

Yesterday, during the eclipse show, a park visitor asked about the lunar eclipse cycle. I shared that I did not fully know the math or the patterns but that solar and lunar eclipses were interrelated and that long-period "Saros" cycles came into play. I offered to get my RASC Observer's Handbook to read the essay but they declined.🙂

Today I read the entry in the 2022 edition. Briefly, there are "eclipse seasons" that occur two times in a year, each lasting approximately 32 days, due to the inclination or tilt of the Moon's orbit. For 2022, they occur in Apr/May and Oct/Nov. They shift each year, backwards in the calendar, so it's good to check a trusted resource (like RASC) for current information. Within a year, there can be between 4 and 7 eclipses, lunar and solar combined, within these two seasons.

The 2022 events:

  • Apr 30: partial solar eclipse
  • May 16: total lunar eclipse
  • Oct 25: partial solar eclipse
  • Nov 8: total lunar eclipse

The Saros cycle, known from ancient times, is approximately 18 years and it says that the Earth will be nearly exactly in the same position in its orbit, the same distance from the Sun, and with the same latitude region will be exposed to an eclipse.

See page 122 for the essay Eclipse Patterns by Roy Bishop.

Or see the Eclipse Wise website listing for 2022 events.

The Astronomer-In-Residence program is coordinated by the Allan I Carswell Observatory (AICO) at York University with the Killarney Provincial Park Observatory (KPPO).

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