This is an engineering prototype, a thermal-mechanical unit, of one of two Hydrogen Alpha telescopes flown on the Apollo Telescope Mount designated H-alpha #2. These telescopes provided images of the sun in the red light of the hydrogen alpha line (6563 Angstroms) and were intended to locate areas of interesting solar activity and to aim and align the other solar observation instruments. Both telescopes were equipped to provide TV pictures and one of those (H-alpha #1) also provided a simultaneous photographic record.
NASA transferred the instrument to the NASM in June 1974.
Transferred from the George S. Marshall Space Flight Center