NASA image captured October 7, 2010  View a video of this event here: <a href="http://www.flickr.com/photos/gsfc/5099028189">www.flickr.com/photos/gsfc/5099028189</a>  This was a first for SDO and it was visually engaging too. On October 7, 2010, SDO observed its first lunar transit when the new Moon passed directly between the spacecraft (in its geosynchronous orbit) and the Sun. With SDO watching the Sun in a wavelength of extreme ultraviolet light, the dark Moon created a partial eclipse of the Sun.  These images, while unusual and cool to see, have practical value to the SDO science team. Karel Schrijver of Lockheed-Martin's Solar and Astrophysics Lab explains: &quot;The very sharp edge of the lunar limb allows us to measure the in-orbit characteristics of the telescope e.g., light diffraction on optics and filter support grids. Once these are characterized, we can use that information to correct our data for instrumental effects and sharpen up the images to even more detail.&quot;  To learn more about SDO go to: <a href="http://sdo.gsfc.nasa.gov/" rel="nofollow">sdo.gsfc.nasa.gov/</a>  Credit: NASA/SDO  <b><a href="http://www.nasa.gov/centers/goddard/home/index.html" rel="nofollow">NASA Goddard Space Flight Center</a></b> enables NASA’s mission through four scientific endeavors: Earth Science, Heliophysics, Solar System Exploration, and Astrophysics. Goddard plays a leading role in NASA’s accomplishments by contributing compelling scientific knowledge to advance the Agency’s mission.  <b>Follow us on <a href="http://twitter.com/NASA_GoddardPix" rel="nofollow">Twitter</a></b>  <b>Join us on <a href="http://www.facebook.com/pages/Greenbelt-MD/NASA-Goddard/395013845897?ref=tsd" rel="nofollow">Facebook</a></b>
SDO Observed its First Lunar Transit
On Mar. 6, 2019, SDO observed a long lunar transit - with a twist. The shadow of the Moon in SDO's images first touched the limb of the Sun at 2200 UTC (5pm EST) on Mar. 6, making its way across and finally left the solar disk at 0209 UTC on Mar. 7 (9:09 pm EST, Mar. 6). The moon's apparent reversal is caused by SDO first overtaking the moon in its orbit, then the moon catching up as SDO swings around Earth's dusk side. During the transit the Sun moves in the frame as the telescopes cool and flex in the lunar shadow. Note that the edge of the Moon is very sharp because it has no atmosphere.  Movies available at https://photojournal.jpl.nasa.gov/catalog/PIA21905
Criss-Crossing Lunar Transit