Columbia subject headings:
Astronomical museums--United States--Directories.
Astronomical observatories--United States--Directories.
Planetariums--United States--Directories.
Harvard subject headings:
Astronomical museums--United States--Directories.
Astronomical observatories--United States--Directories.
Planetariums--United States--Directories.
Princeton subject headings:
Astronomical museums--United States--Directories.
Astronomical observatories--United States--Directories.
Planetariums--United States--Directories.