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Observatory FAQs

Observatory Programs & Events

Learn about our programs here. View our past lectures and virtual programs on YouTube and sign up for our newsletters to stay informed about future programs.

If your child is old enough to be in school, they will probably enjoy stargazing with us as well!

You do not need your own telescope to participate. In addition to the PlaneWave Instruments CDK700 telescope in the dome, we have smaller telescopes for everyone to enjoy on the observation deck. If you would like to bring your own telescope, please let us know ahead of time by contacting the Observatory Team.

While we do make accommodations for professionally trained service animals, we generally do not allow pets in the Library and Observatory. While there are a number of reasons for this policy, one of our specific concerns during our night programming is the safety of the animals. Given the large crowds in relatively low lighting with much of their attention skyward, small animals could be in danger of being kicked or stepped on accidentally. We want to ensure everyone’s pets are kept safe. Safety is paramount at all of our events, and that includes the safety of our pets.

Under certain conditions, the Observatory may be rented for private events for a fee, as defined in City of Rancho Mirage Municipal Code Sections 9.30.080 and 9.30.082. Click here for the Observatory Use Application.

If you have trouble viewing the document or have any further questions, please contact the Observatory Team.

About Rancho Mirage Observatory

The City Council saw an opportunity to grow the Rancho Mirage Library campus and further enhance the Library’s mission of lifelong learning. The Rancho Mirage Public Library has evolved over the years from a library to an educational and cultural center for all of our valley’s residents and visitors. The Observatory offers educational programming and opportunities for all ages and levels of expertise from the young to the young at heart, from the amateur to the expert. The Observatory is free and open to the public and brings the Library’s mission of lifelong learning to an even higher level. The sky’s the limit!

The total cost of the Observatory project, which includes all exploratory costs, specialized surveys, construction, and all equipment was $4.2 million. The Observatory was funded with non-City trust fund monies that would have been returned to the state if not spent locally. The ongoing operations and maintenance of the Observatory are being funded with restricted library funds.

The Observatory is a regional scientific asset. Like the Library, it is available and free of charge to all valley residents and visitors.

The Observatory is open for a daily facility tour Tuesday through Thursday at 3:00pm. Additionally, the Observatory will be open for programs and other events regularly. Specific events, dates, and times can be found at The Library & Observatory Website and on the calendar of events for more details.

The weather station at Rancho Mirage Observatory is an important component of the overall function of the Observatory. High-speed winds, rain, and other inclement weather can reduce the lifetime of the sensitive equipment inside the dome. The weather station not only informs us about sky conditions but also automatically protects the observatory systems. It both prevents the opening of the dome in poor conditions and automatically closes an open dome and protects it in the event of deteriorating conditions.

The Rancho Mirage Observatory is a public education center built specifically for you! From planning through construction and into programming, this Observatory is intended as a place dedicated to astronomy for the public.

Construction Facts

1,400,000 pounds of concrete and 4.5 miles of rebar reinforcement were used to construct the observatory.

The Observatory building is designed with round concrete footings that go at least 20 feet into the earth.

The main exterior materials used for construction of the Observatory were chosen for their durability: concrete, steel, and wood. Particularly interesting is the wood decking and wood siding on the viewing deck. The Brazilian wood material is called Ipe and is one of the world’s most dense wood types – it doesn’t even float!

The telescope sits on a 16-foot-high concrete pedestal that is anchored to a 120,000-pound concrete footing, which is completely isolated from the rest of the building. In essence, the building was constructed around the telescope pedestal. This minimizes the transfer of vibrations from the building to the telescope.

The telescope room has its own air conditioning system. It might be cool or warm in the telescope room as the air conditioning system works to keep the telescope mirror close to outside ambient air temperature.

The dome roof automatically spins and opens to the night sky at the touch of a button. The dome can spin 360 degrees in either direction without stopping. The dome roof weighs approximately 4,800 lbs.

The four telescope workstations on the viewing deck are equipped with power and data links to an IT rack housed in the Cosmic Office.

The IT racks in the Cosmic Office have 10 terabytes of storage and a 10 gigabit per second connection to the Library via fiber optic line. The Library has an additional 10 terabytes of storage dedicated for Observatory programs.

Telescope Facts

Our main telescope is a PlaneWave Instruments CDK700. This telescope uses a Corrected Dall-Kirkham optical system. This recently developed system uses an ellipsoidal primary mirror, a spherical secondary mirror, and a series of correcting lenses to collect light so that it can either enter a camera or eyepiece. For more information on the specifics of CDK optical systems, click here.

The primary mirror is 700 mm in diameter (or 27.56 inches). This is the most critical dimension of a telescope because telescopes need to collect as much light as possible to view very faint objects. A larger primary mirror results in a better ability to collect light.

Our PlaneWave Instruments CDK 700 telescope can observe objects over 50 million light-years distant. In other words, our telescope can observe objects that are further than 3 trillion times the distance between the Earth and the Sun.

Bode’s Galaxy, recently captured by our telescope, is approximately 11.8 million light-years from Earth. For comparison, the center of our Milky Way Galaxy ranges from 24-28,000 light-years from Earth.

The quality of an astronomical observatory and the images it takes is related to an atmospheric condition called seeing. Seeing is a way of describing the amount of atmospheric disturbance in an image and relates to the best possible angular resolution of a telescope system at the time of observing. As part of the construction of the Observatory, Paul Gardner of Observatory Systems conducted a series of tests with the Rancho Mirage Observatory. His tests were able to measure a seeing value of 1.035 arcseconds (or less than one thousandth of a degree) with our telescope. This shows that RMO’s systems and location can produce phenomenal images for both educational and research purposes.

We refer to the Observatory as research grade because the facility is capable of conducting research-level work similar to other research-focused observatories.

No, in general we will not be able to use the telescope during the day. However, we may be able to view a few objects in the Solar System near dusk and dawn.

Yes! While there are more hours of daylight in the months surrounding the summer solstice, there is still plenty of time during the night for observing the sky.

Yes! In addition to the PlaneWave Instruments CDK700 telescope, we have several smaller telescopes to help supplement our various programs. Some of our smaller telescopes include the following models: Celestron CPC Deluxe 925 HD, Lunt LS100T Hα, Celestron CGEM II 1100, Orion SkyQuest XT10 Deluxe, and Celestron NexStar 6SE.

Unfortunately, due to schedule limitations, we are unable to schedule 1-on-1 lessons with the City Astronomer at this time. However, your local amateur astronomy club may be able to help. Find a club near you today!

It is helpful for you to assess your current level of interest and familiarity with the night sky before you make any purchases. If you are just starting out, it is best to first get to know the night sky, such as familiarity with sky maps and understanding the movement of the night sky with the naked eye and binoculars. And from there you can begin to consider getting a quality telescope and it will be worth so much more to you by that point.

If you are in the early stages of the hobby, we recommend you check out this book, which is available in our library’s collection: Sky Atlas for Small Telescopes and Binoculars by David S. and Billie E. Chandler. This short guide helps you get started. It also has sky maps with objects viewable with the naked eye, binoculars, and small telescopes, and excellent descriptions to help you find the objects. If you believe you are already beyond the scope of the book, please reach out to the Observatory Team.

Viewing objects “upside-down” has no bearing on a telescope’s quality. All telescopes use lenses or mirrors (or both) to collect the light and bring it to your eye, oftentimes with the image inverted, rotated, or mirrored. To achieve a specific orientation through the eyepiece you would need to add optics, which may reduce light throughput and introduce aberrations, therefore, most astronomers do not go that route. If you get into astrophotography, any preferred orientation of an image is a simple change in photo editing software.

Astronomy Fun Facts

  • Details on planets such as Mars and Jupiter
  • Nebulae: enormous clouds of gas and dust spread over vast regions of space
  • Large clusters of stars
  • Distant galaxies

A light-year is the distance light travels in one year. In a vacuum, light travels at about 300,000 kilometers per second (or about 186,000 miles per second). At this speed, light travels from the Earth to the Moon in about 1.3 seconds! Thus, over one year, light travels about 9.46 trillion kilometers (about 5.88 trillion miles).

The average distance from the Earth to the Moon is around 384,000 kilometers (239,000 miles) but this distance varies by over 10,000 kilometers as the Moon revolves around the Earth.

The distance to the Moon has been measured very precisely using lasers and reflectors placed on the Moon during the Apollo Program and several other missions.

It takes light from the Sun a little more than 8 minutes to reach the Earth. That translates to approximately 150 million kilometers or 93 million miles. This distance is the basis for the Astronomical Unit (AU). Thus, the distance to the Sun is about 1 AU.

Besides the Sun, the nearest star is Proxima Centauri. It is approximately 4.2 light-years from Earth and has one known planet. Unfortunately, we cannot see this star from Rancho Mirage because you must be located south of a latitude of about 27°N to have any chance to see it.

The center of the Milky Way Galaxy ranges from 24-28,000 light-years away in the constellation of Sagittarius. At the center of the Milky Way is a supermassive black hole that is around four million times the mass of the Sun.

“Though my soul may set in darkness, it will rise in perfect light;
I have loved the stars too fondly to be fearful of the night.”

-Sarah Williams (1837-1868), Poet

Thanks to the support of our generous donors.
Unless otherwise noted, programs are presented by the
Rancho Mirage Library and Observatory Foundation.