NASA’s Solar Dynamics Observatory (SDO) witnessed a rare double solar eclipse within hours on July 25th. The first event, a partial eclipse, occurred as the Moon transited between the spacecraft and the Sun. The second event, a total eclipse, was caused by Earth’s passage between the SDO and the Sun.
Operating in Earth orbit since 2010, the SDO maintains constant solar observation via a geosynchronous orbit, completing one full revolution around Earth daily. Its inclined orbit minimizes planetary interference but cannot prevent occasional observational blocks by the Moon or Earth.
Lunar transits occur several times annually. The July 25th partial eclipse began at 02:45 UTC, lasted approximately 50 minutes, and was the fourth such lunar event since April. It obscured up to 62% of the Sun’s disk, making it the most extensive lunar transit in this period. Earth-induced eclipses happen about twice yearly during three-week “eclipse seasons,” with daily blocking events. The SDO is currently experiencing its 31st eclipse season, which began July 10th and extends to August 7th.
The Earth eclipse on July 25th commenced at 06:30 UTC, roughly three hours after the lunar transit concluded, and ended just before 08:00 UTC. This marks the third instance of the SDO observing a double eclipse within one day, following similar events in 2015 and 2016 – the latter featuring near-simultaneous transits of both the Moon and Earth.
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