LIMITED PARKING

due to lingering snow cover

Custer Institute and Observatory is Long Island's oldest public observatory - open from 7 pm to midnight on Saturdays! 

Explore the night sky with our volunteers, powerful telescopes, tours, and live events.

Silhouette of a person under a colorful night sky filled with stars and the Milky Way.

Join us every Saturday night for public observing sessions, where you can explore the cosmos through our powerful telescopes.

When the skies are clear, our knowledgeable volunteer staff will guide you on a tour of the stars, planets, and beyond.

Saturday Night Public Observing
Doors open at 7 PM
Observing from dark until midnight (weather permitting)

All observing takes place outdoors—please dress appropriately. Seasonal hours and times of darkness may affect skywatching times.

Learn more

EVENTS

Outdoor Events: Most events take place on our lawn. We encourage you to bring a blanket or chair to make your experience more comfortable.

Rain Dates: Rain dates (when necessary) will be noted on our website, social media, and/or Eventbrite for your convenience.

Saturday, February 21

10:00am-3:00pm @ Silversmith Corner

5:00pm-midnight @ Custer Observatory

SOUTHOLD TOWN WINTERFEST

Registration Not Required

Custer Observatory will again be participating in Southold Town's annual Winterfest!  From 10:00am-3:00pm join us for solar observing (weather permitting) at our booth on Silversmith's Corner (across from IGA).

Later in the evening, Custer Observatory will be open to the public for stargazing beginning at 5pm until midnight. Staff will provide guided tours of the night sky through powerful telescopes (weather permitting).  Additionally, tours of the facility and exhibits will be offered periodically throughout the night (regardless of weather). 

Suggested Donation for observatory tours/stargazing: $5 Adults, $3 Children under 12.  Registration not required.  


Saturday, March 21. 7pm - Sunday, March 22. 7am

An all night event!

THE MESSIER MARATHON:

110 objects. one night.

Register

Join Custer Observatory for our first-ever Messier Marathon! This is the ultimate deep-sky challenge: we’ll attempt to locate all 110 objects in Charles Messier’s famous catalog—from galaxies to nebulae—between sunset and sunrise. Because of the timing of the sun’s path, March is the only time of year when it's possible to see all 110 objects in one go.

The Messier objects are a set of 110 astronomical objects catalogued by the French astronomer Charles Messier. This list, which Messier created in collaboration with his assistant Pierre Mechain, is known as the Messier Catalogue. The Messier catalogue is one of the most famous lists of astronomical objects, many of which are still referenced by their Messier numbers today. The catalogue includes most of the deep-sky objects (nebulae, star clusters, galaxies) that can be easily observed from Earth's northern hemisphere. If you’ve never participated in a Messier Marathon before, this is a great opportunity to challenge yourself and experience the wonders of the night sky just as Charles Messier did over 200 years ago! This isn't just a viewing—it’s a marathon. We’ll be hunting down all 110 nebulae, star clusters, and galaxies in the Messier Catalog in a single dusk-to-dawn session!

This is a hands-on, outdoor observing event and requires that participants bring their own telescope and have a working knowledge of the night sky. Please also bring a red flashlight or headlight. Expect cold March nights; bring a blanket and/or warm clothing for comfort during viewing. The observatory facility will be open all night as a warming center for breaks, resting and conversation. Light refreshments will also be available.

This event is weather-dependent and requires clear skies. If cloud cover greater than 40% is forecast, the event will be canceled. A final weather determination will be made the morning of the event (there is no rain date for this event). Cancellation will be announced on Custer Observatory's website event listing and an email notification will be sent to those who have pre-registered. Full refunds will be issued in the case of cancellation.

$10 General Admission, Custer Observatory Members FREE. Due to limited space, registration is strongly encouraged. All event updates including weather cancellations will be sent to the email address used at ticket checkout. Please check your email and/or Custer Observatory's website the morning of the event in case a cancellation is announced. 

PROGRAMS + RESOURCES

  • Astronaut on the moon holding a yellow umbrella with Earth in the background.

    WEATHER

    Clear Skies Ahead!

    Find the latest weather forecasts tailored for astronomers, including cloud cover, precipitation, dewpoint, wind conditions, and Moon phases. Our easy-to-read key helps you decide if it’s a perfect night to bring out your telescope!

  • Silhouettes of musicians and text "Music Under the Stars The Music Project at Custer Institute & Observatory."

    THE MUSIC PROJECT

    Bring music and stargazing together at Long Island’s oldest public observatory, tMP blends the performing arts with science and discovery. A unique stargazing experience follows each performance where audiences are invited to explore the night sky with guidance from our expert volunteer staff, using our historic observation dome and an array of on-site telescopes.

  • WHAT'S UP?

    Skywatching highlights each month, provided by NASA.

  • Telescope on tripod with accessories in a grassy field with trees in the background.

    RESOURCES

    Whether you're a seasoned astronomer or just starting your journey into the cosmos, our collection of resources will help guide you.

  • Blue background with white and gold text reading "Custer Institute & Observatory Scholarship Program" and a stylized star and comet graphic in the top left corner.

    SCHOLARSHIP

    Supporting the Next Generation of Scientists & Innovators. Available to High School Seniors throughout the North Fork.

  • Illustration of Custer Institute Observatory with text "Honey of the Stars, 100% Pure Local Honey, Custer Institute Observatory, Southold, New York" and "Custer HoneyBee Club" on a building, under a starry sky.

    HONEY BEE CLUB

    Custer's Honey Bee Club is an educational program focused on environmental sustainability and honeybee stewardship.

    Send an email to learn more.

Support the North Fork Dark Sky Coalition

Take action to protect our night skies:

  • Pledge to turn off unnecessary lights and spread awareness,

  • Update Your Lighting by using dark sky-friendly fixtures and warm-toned bulbs, and

  • Become a Partner to advocate, educate, and support local Dark Sky initiatives.

Take the pledge and join the North Fork Dark Sky Coalition

Learn more
Night sky with Milky Way over waterfront building and boats at a dock.

AFFILIATIONS + SUPPORTERS + PARTNERS

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