Two eclipses on the same day means that NASA’s Solar Dynamics Observatory (SDO), a satellite spending five years studying our sun, must be enjoying its spring eclipse season. Karen C. Fox for NASA’s Goddard Space Flight Center explained that eclipse season comes twice a year for the satellite. During that time, the earth will block SDO’s view of the sun during some part of each day.
What made today’s photography special is that the moon also eclipsed the SDO’s view of the sun, creating a second partial eclipse and a golden opportunity to compare the difference between an eclipse caused by a planet with an atmosphere (our earth) and the airless moon.
The photo on the left is from the earth’s transit of the sun. It looks fuzzy because of the sunlight that can slip through the atmosphere. The photo on the right has a crisp edge because it’s from the later transit of the moon across the sun’s face. The first picture was snapped around 2:20 AM EDT, and the second was taken around 8:00 AM EDT.
Yes, apparently, even satellites are subject to daylight saving time.
The Solar Dynamics Observatory was launched on Feb. 11, 2010, and it is expected to fulfill its primary mission for over five years, during which time it is being used to better understand how the sun can impact life on earth. Since solar flares can interfere with human communications and energy infrastructure, it can be important to learn how to predict them. A maximum of solar flare activity is forecast to occur in May.
Beautiful as the photos are, the SDO is actually designed to minimize the eclipses its encounters, since they interfere with its mission to view the sun. The current eclipse season will end on March 26.
The transits may represent a minor nuisance to science, but I think most of us would envy the SDO’s opportunity to photograph two eclipses within just a few hours.
[photo courtesy NASA/SDO]