Columbia subject headings:
Optical instruments--Design and construction--Congresses.
Telescopes--Design and construction--Congresses.
Harvard subject headings:
Mirrors--Design and construction--Congresses.
Optical industry--Congresses.
Reflecting telescopes--Design and construction--Congresses.
Princeton subject headings:
Optical instruments--Design and construction--Congresses.
Telescopes--Design and construction--Congresses.