                        Astronomy Picture of the Day

    Discover the cosmos! Each day a different image or photograph of our
      fascinating universe is featured, along with a brief explanation
                    written by a professional astronomer.

                                 2022 May 19

                           A Digital Lunar Eclipse
                   Image Credit & Copyright: Michael Cain

   Explanation: Recorded on May 15/16 this sequence of exposures follows
   the Full Moon during a total lunar eclipse as it arcs above treetops in
   the clearing skies of central Florida. A frame taken every 5 minutes by
   a digital camera shows the progression of the eclipse over three hours.
   The bright lunar disk grows dark and red as it glides through planet
   Earth's shadow. In fact, counting the central frames in the sequence
   measures the roughly 90 minute duration of the total phase of this
   eclipse. Around 270 BC, the Greek astronomer Aristarchus also measured
   the duration of total lunar eclipses, but probably without the benefit
   of digital watches and cameras. Still, using geometry he devised a
   simple and impressively accurate way to calculate the Moon's distance
   in terms of the radius of planet Earth, from the eclipse duration.

               Tomorrow's picture: a view from Earth's shadow
     __________________________________________________________________

       Authors & editors: Robert Nemiroff (MTU) & Jerry Bonnell (UMCP)
            NASA Official: Phillip Newman Specific rights apply.
                NASA Web Privacy Policy and Important Notices
                      A service of: ASD at NASA / GSFC
                             & Michigan Tech. U.

