Gilbert Rotary Centennial Observatory Mission and Purpose

The GRCO is fun for the entire family!

The Gilbert Rotary Centennial Observatory (GRCO) is open to the public each Friday and Saturday evening (weather permitting) from sunset until 9:30 PM. The park closes at 10 PM.

Join us the second Friday of each month for our Public Star Party. Additional telescopes supplied by members of the East Valley Astronomy Club are available for free public viewing, and there is also an astronomy related talk in the adjoining public library at 7:30 PM. If you are interested in purchasing a telescope, or have questions about a telescope you already own, this is a great way to view a variety of telescopes and learn from our experienced volunteers.

From time to time we are also open for special events and solar viewing. Please check the Riparian website at for further information.

Attendance is free, however a voluntary donation of $3.00 for an adult or $5.00 per family is suggested. Any and all donations are greatly appreciated, and are used to maintain the observatory equipment and to improve the astronomical educational experience for the public. Children under High School age are welcome when accompanied by an adult. Groups of fifteen or more should contact the GRCO Manager for advance arrangements.

Private sessions are available by reservation by contacting the GRCO Manager. A maximum of twenty people can be scheduled for any session. These sessions will incur a fee of $5.00 per person, payable at the time of reservation. All fees will be refunded for events cancelled due to weather. The minimum fee is $45.00. Organized youth groups working on astronomy awards, such as Boy Scouts, Cub Scouts, Girl Scouts, or any other formally organized and recognized group should contact the GRCO manager for specific arrangements and/or possible fee waivers.

Observatory Etiquette

We ask that viewers do not physically touch the telescope or eyepiece (it is tempting for viewers of all ages) because the telescope is always moving by computer control, and touching will cause the image to shake. Please refrain from using flashlights or looking at your cellphones during your visit to the observatory. The best viewing is obtained when your eyes are “dark adapted”. We use red lights to assist your night vision, and looking at bright lights will instantly cause your eyes to react and lose the ability to more easily see fainter objects. This is also why flash photography is not allowed. The observatory staff will choose objects that are available for viewing that evening. Please feel free to stay and watch our educational videos on the patio as you wait. We will try to see several objects during an evening, but that is dependent on the number of people waiting in line. Ask our volunteers any astronomy related question that is on your mind, but please be respectful of other guests who are waiting to view.

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