Welcome to the Custer Institute & Observatory

Long Island's oldest public observatory (est. 1927)

For the Curious

The Custer Institute and Observatory is Long Island's oldest public observatory (est.1927). Open to the public every Saturday evening from dusk until midnight, our staff of volunteers will give you a tour of the facilities and the night sky through our powerful telescopes. Custer has a library, museum, and gift shop. Frequent lectures, classes,concerts, art exhibits and other special events.

Custer Links

Check our local weather before making the trip!


  • Clouds, fog, and rain, are not good nights for observing, but are good nights for members to work on indoor projects and maintenance. Find out about becoming a member here.
  • A bright, full moon, while beautiful, makes it difficult to see anything but the brightest objects.
  • You can check the moon-phase calendar here.
  • A quick look at the weather can be found here.
  • When the sky is clear, we observe from dark until Midnight.
  • Doors open at 7pm




    • Southold Weather: National Weather Service

    • Astrospheric: weather forecasting for astronomers, astrophotographers, and most of all explorers.

    • Enhanced Radar Image From National Weather Service Upton, NY Radar

    • Accuweather: Southold

    • Weather Underground: Southold

    • News12 Long Island Weather

    • North East MODIS Image Today

      • The MODerate Resolution Imaging Spectroradiometer (MODIS) is an imaging instrument flown onboard NASA's Earth Observing System (EOS) series of polar orbiting satellites. Scientists at SSEC are using MODIS data to advance understanding of the earth/atmosphere system, particularly through research on cloud detection, distribution, and composition; as well as retrieving atmospheric temperature and moisture.

      SSEC has a direct broadcast downlink that receives MODIS data in real time. SSEC scientists have developed software (International MODIS/AIRS Processing Package (IMAPP)) to process direct broadcast data. IMAPP allows any ground station in the world capable of receiving direct broadcast from Terra or Aqua to produce calibrated and geolocated MODIS radiances (Level 1), along with a select group of science products (Level 2). IMAPP is derived from the operational MODIS processing software developed at NASA Goddard, and is modified to be compatible with direct broadcast data.