The Moon came in between the <a href="https://en.wikipedia.org/wiki/Solar_Dynamics_Observatory" class="extiw" title="en:Solar Dynamics Observatory">Solar Dynamics Observatory</a> (SDO) satellite and the <a href="https://en.wikipedia.org/wiki/Sun" class="extiw" title="en:Sun">Sun</a> (seen here in 304 Å extreme <a href="https://en.wikipedia.org/wiki/ultraviolet" class="extiw" title="en:ultraviolet">ultraviolet</a> light) and produced a partial <a href="https://en.wikipedia.org/wiki/solar_eclipse" class="extiw" title="en:solar eclipse">solar eclipse</a> from space. For 1 hour and 41 minutes team SDO observed the lunar transit. This event only happens a few times a year, but it does give the SDO team an opportunity to better understand the AIA instrument on SDO and give it a fine-tuning. The sharp edge of the lunar limb helps researchers measure the in-orbit characteristics of the telescope, e.g., how light diffracts around the telescope's optics and filter support grids. Once these are calibrated, it is possible to correct SDO data for instrumental effects and sharpen the images even more than before.
NASA/SDO
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