The US Naval Observatory has processed several new collections related to the history of astronomy and exploration that are now available for research:
 
Transit of Venus Expeditions Collection (USNO sent expeditions in 1874 and 1882)
Hall Family Collection (Asaph Hall discovered the moons of Mars in 1877 at the Naval Observatory)
 
Additionally, the USNO has begun scanning their astronomical glass plate collection as well.
Margaret Huettl answering questions at the Why Go to the Moon_ event, held at the Adler Planetarium on July 19, 2019

Margaret Huettl answering questions at the event "Why Go to the Moon" held at the Adler Planetarium on July 19, 2019.