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.

STARGAZING NIGHTS @ SILVER SANDS

Friday, April 17. 7:30 - 9:30pm

Enjoy a special night of stargazing on the beach in partnership with Silver Sands Greenport!

Join us on Friday, April 17th from 7:30pm-9:30pm for an evening of early spring stargazing at Silver Sands, hosted at The Boathouse at 1400 Silvermere Road in Greenport. Guided by the team from Custer Observatory, guests will explore stars, planets, and distant galaxies through high-powered telescopes set along the beach overlooking Pipes Cove. Beginning at sunset for a beautiful transition from dusk into full night sky viewing, Mars and Venus will be visible briefly in the early evening, while Jupiter will remain visible longer for extended viewing. This is also an excellent opportunity to explore the Big Dipper in detail, and if conditions allow, we may observe the Coma Berenices star cluster.

To keep the night comfortable, complimentary hot cocoa, hot cider, and blankets will be available as you take in the sky above. Admission is $15 for adults and $5 for children, with all proceeds directly supporting Custer Observatory and its mission to bring astronomy to the community.

Turn the experience into a full evening by pairing stargazing with dinner at The Boathouse before or after the program. Space-themed films will be playing on the jumbo TV, extending the atmosphere well beyond the shoreline. Whether you are deeply familiar with the night sky or simply curious, this is an intimate and memorable way to spend a late winter evening on the North Fork.

Space is limited, so reserve now! Note: This is a weather-permitting event. In the event of cancellation, updates will be posted on Custer Observatory’s website and full refunds will be automatically issued for cancelled events.

CELEBRATING INTERNATIONAL DARK SKY WEEK

Saturday, April 18. 7:00pm - midnight.

Discover the night at Custer Observatory as we celebrate International Dark Skies Week 2026!

Come visit Custer Institute and Observatory, Long Island's oldest public observatory (est.1927), to experience the dark skies in your neighborhood and learn about what you can do to protect the night sky.

Artificial light at night has revolutionized the way we live and work outdoors, but it has come at a price. When used indiscriminately, outdoor lighting can disrupt wildlife, impact human health, waste money and energy, contribute to climate change, and block our view of the universe.

Custer Institute and Observatory is located beneath some of Long Island's darkest skies, where on a clear dark night you can still see the Milky Way galaxy. Come join us in discovering (or re-discovering) the North Fork's night sky!

If the weather is clear, the Custer Observatory dome and other telescopes on site will be open for viewing and guided by Observatory staff. Guests may arrive any time between 7:00pm and 11:30pm. Stargazing (weather permitting) will begin as soon as skies are dark.

Suggested Donation: $5 Adult, $3 Children Under 16, Observatory Members FREE. Your donations help us to continue our mission and are greatly appreciated. We ask that you register in advance as this will guide our preparations and plans for the evening, though registration is not required to attend.

PROGRAMS + RESOURCES

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!

TODAY'S WEATHER
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.

LEARN MORE ABOUT TMP
WHAT'S UP?

Skywatching highlights each month, provided by NASA.

VIEW VIDEO
RESOURCES

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

RESOURCES
SCHOLARSHIP

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

LEARN MORE
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.

LEARN MORE & JOIN

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