John Mosley

John Mosley is a retired astronomer, and for the last seven years he has spent eight months per year in a motorhome.

Contact John Mosley:

Articles by John Mosley

• The true origin of Halloween

  Wednesday, October 23, 2013

  Some holidays fall on the same date each year because they commemorate a specific event. Others drift by up to several weeks from year to year. The most familiar example is Easter, which is set as the first Sunday after the first full moon after the spring equinox. Perhaps surprisingly, Halloween is also a date that is determined astronomically.