Photographic Plate, M13


Display Status:

This object is on display in the Explore the Universe exhibition at the National Air and Space Museum in Washington, DC.

Collection Item Summary:

This set of two original photographic plates is of the globular cluster Messier 13 (M13), one of the brightest clusters of its type in the northern skies. These plates were obtained by astronomer Wayne Osborn in July 1968, working with other astronomers as part of an extensive systematic series of photographic and photoelectric observations in the 1960s through 1980s searching for stars that vary in light in the cluster. Known as Cepheid variables, their variation reveals their intrinsic brightnesses, which yields a measurement of distance to the cluster. The photographic observations were made at the 61-inch (1.5 meter) astrometric reflector at the U. S. Naval Observatory Flagstaff Sation.

Collection Item Long Description:

Inventory Number


Credit Line

On loan from Pisgah Astronomical Research Labatory (PARI), Rosman, NC


Pisgah Astronomical Research Institute


Wayne Osborne


Glass with photographic emulsion, within paper folder


  • 3-D: 17.8 × 12.7 × 0.1cm (7 × 5 × 1/16 in.)
  • 2-D - Unframed (H x W) (Paper Sleeve): 14 × 19cm (5 1/2 × 7 1/2 in.)

Data Source

National Air and Space Museum

Restrictions & Rights

Do not reproduce without permission from the Smithsonian Institution, National Air and Space Museum