cycle with two eclipse seasons
lasting 100 years each.
Any spacecraft observing the sun from an orbit around Earth has to contend with such eclipses, but SDO's orbit is designed to minimize them as much as possible, with only two three-week eclipse seasons each year.
Washington, Mar 12 ( ANI ): NASA's Solar Dynamics Observatory (SDO) entered its semi-annual eclipse season on March 2, 2013 - a period of three weeks when Earth blocks its view of the sun for a period of time each day.
The 2013 spring eclipse season continues until March 26.
Outside of two "eclipse seasons" each year, the Moon always appears to pass slightly to the north or south of the Sun in our skies.
Even when conditions are exactly right, which happens about once in every three eclipse seasons (18 months), the total eclipse can be seen from only a very narrow "band of totality"--a few tens of miles wide--that crosses an entire hemisphere of Earth in one day.
It also finds eclipse seasons
, positions and distances of the Sun and Moon for any moment, times and distances of perigee and apogee, and more.
"Eclipse seasons" of Iapetus come only every 15 years, twice in each orbit of Saturn around the Sun.
Mitsuru Soma (National Astronomical Observatory, Tokyo), who called attention to the current eclipse season, is urging suitably equipped astronomers to make photometric timings.
Using this model, we can also explain the more difficult concept of eclipse seasons
, in which eclipses are bunched together at half-year intervals.