Take a Weekend Public Tour of the most productive observatory in history! Saturday and Sunday tours start at 1:00 pm, and run until December 2.  Please note that, for the fall season, the Cosmic Café hours have changed to 10:00 am to 5:00 pm. The gates on the weekend will continue to open at 8:30 am until the end of the season, on December 2. The grounds are open every day of the year, except when snow and ice, or other hazardous conditions warrant a temporary closing.

George Ellery Hale

Pioneering Astrophysicist

Founder of Mount Wilson Observatory

For the first half of the 20th Century, Mount Wilson was the most famous observatory in the world. The biggest telescopes were here, and their new designs were changing the way astronomy was done. Among the many discoveries made on the mountain, a few revolutionized our understanding of our place in the Universe. Here, for the first time, Harlow Shapley measured the size of the Milky Way Galaxy and located our position in it, far from the center. Then Edwin Hubble proved that the mysterious spiral nebulae, which astronomers had speculated about for decades, were in fact distant galaxies similar to our own. Then Hubble teamed up with Milton Humason and discovered that this immense Universe was expanding. Space itself was getting bigger. This finding, when run backwards in time, led straight to the Big Bang Theory. This is where modern cosmology began. In our long search for our origins, Mount Wilson holds a unique place in human history. Today, our original solar and nighttime telescopes, the world’s largest for two generations of astronomers, have been joined by the new CHARA array, which has the highest resolution of any optical or infrared system ever built, achieving unprecedented views of the stars.

Hubble guiding Mount Wilson's 100-inch Telescope in 1924, shortly after he proved the existence of distant galaxies. Photo: Carnegie/ Huntington Library. Photos at the top of the page: 1-Matt Adame, 2-MWO, 3-Steve Padilla. Photos below, left to right: I-MWO, 2-Dave Jurasevich, 3-MWO, 4-NGC 7331 by George Willis Ritchey.
Explore Mount Wilson in Person

Explore Mount Wilson in Person

Explore Mount Wilson On-Line

Explore Mount Wilson On-Line

Support Mount Wilson Observatory

Support Mount Wilson Observatory

  • Help keep the Observatory operations going and preserve its famous telescopes for future generations, Donate!
  • Join the people who keep the Observatory programs going, Volunteer.
  • Next year, run the Third Annual Mount Wilson Observatory  5K, a fundraiser to add restrooms, benches, and scenic overlooks to the Observatory.

Thank you to all who contributed to our first Triple Match!

We raised $78,000 to get started with our plans to build much needed public restroom facilities on the eastern side of the Observatory near the telescope domes. More funds will be needed to complete the project, as construction on the mountain, a mile above Los Angeles, is costly, but it is a fantastic start. When finished, it will greatly improve the experience of our many visitors, such as school groups, hikers, and others who enjoy the mountaintop. Currently, we often need to rent restroom facilities for our special events, which costs us more than $32,000 a year. The new restrooms will make the Observatory more financially sustainable in the long term by sparing us this annual expense.

Dear Friends & Supporters of Mount Wilson Observatory,

This spring, I decided to help the Observatory with a pledge of $20,000 on the condition that others donate an equal amount. It quickly evolved into a triple match, with a small group—trustees and others—pledging another $20,000. The response was overwhelming: by the deadline, on September 16, not only was the goal met, it was exceeded by more than $6,000!

We at the Observatory are filled with gratitude for those who gave so generously to make this first ever triple match a resounding success. I am so thrilled by the response, I will also match the extra $6,000. My deepest thanks to everyone, near and far, who pitched in!

Our mostly volunteer staff works very hard to maintain and preserve this world-class site both for its ongoing scientific research and its remarkable history. Your help is deeply appreciated by all of us. The love of the place is what keeps us going!

With Heartfelt Gratitude,

Mike Horner
Mount Wilson Trustee

Stephen Hawking, in front of the 150-foot Solar Telescope on one of his visits to Mount Wilson Observatory, June 2, 1990. Photo: Mount Wilson Observatory.

Stephen Hawking (1942-2018)

A giant of human intellect, Stephen Hawking greatly advanced our understanding of the Universe, from black holes to the Big Bang. He was born January 8, 1942, on the 300th anniversary of Galileo’s death, and passed away on March 14th, the anniversary of Einstein’s birth. On his visits to Caltech in Pasadena, he made the pilgrimage up to Mount Wilson (as Einstein did) on several occasions to see the observatory where Hale, Hubble, Humason, and others laid the foundations of modern cosmology, which became his life’s work. Here is a link to Caltech’s news of his passing.

Stephen Hawking’s entry in the visitors book at Mount Wilson, June 2, 1990. He signed with his thumbprint. Photo: David Cendejas/Mount Wilson Observatory


The centennial, paper architectural model of the 100-inch Telescope is now available to download for a small donation to Mount Wilson Observatory. Click here to go to the model page.

Subscribe to Mount Wilson Observatory News for updates on 2018 concerts, lectures, public telescope nights, and other events. Click here.

George Ellery Hale, 1910. Photo: Carnegie/ Huntington Library

The Observatory’s founder, George Ellery Hale, built four telescopes, each one in succession becoming the largest in the world. Here they are shown to the same scale. His first was the 40-inch refractor at Yerkes  (in Wisconsin) on the left, but then he began building the more revolutionary–and more compact–reflector telescopes, using a large mirror instead of a lens. His next two are on Mount Wilson, the 60-inch and the 100-inch. (While not quite as grand as his last, these two had the light-gathering power for astronomers to discover our place in the expanding Universe.) His fourth, the 200-inch Hale Telescope at Palomar, is represented on the right by one of Russell Porter’s famous cutaway drawings. This image has been reversed and extended on the left side for a better comparison of the relative sizes of the full domes. Hale’s telescopes were the biggest from 1897, when Yerkes opened, to 1993, when the Keck telescope in Hawaii was completed–a span of 96 years. To see these drawings enlarged, click here. Drawing credits: University of Chicago/Yerkes Observatory, Carnegie Observatories, Palomar Observatory/Caltech.

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Tuesday, September 18th, 2018 at 5:16am
Second annual 5K run & fundraiser coming on Saturday October 20! Come up for a run around the mountaintop! Info here: https://t.co/EpLL1U8A7n #astronomy #roadrunning https://t.co/fSzbHIfct8 MtWilsonObs photo
Saturday, August 25th, 2018 at 8:48am
Tomorrow! @CarnegieAstro's own @johannateske will be hosting a Q&A after a 7:20 p.m. screening of @Cielo_Film at @ahryafinearts. The documentary is about #astronomy in #Chile and highlights our @LCOAstro. Join us! Tickets: https://t.co/065IpN4S3z https://t.co/gbddvEJlS7 MtWilsonObs photo
Thursday, August 9th, 2018 at 9:28am
Thanks for making this video of my first visit to Mt. Wilson! It was certainly one of the largest telescopes I’ve ever used! @MtWilsonObs #astronomy #telescopes #observatory https://t.co/4nc99IgvJE MtWilsonObs photo
Tuesday, July 31st, 2018 at 8:48am
Fortunate to have this view of Saturn, Mars and Nebulae from Mt. Wilson’s 100inch Telescope last night. @MtWilsonObs https://t.co/PwVU8gMOTV MtWilsonObs photo