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 confirmed 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.

A publicity photo of astronomer Edwin Hubble guiding Mount Wilson’s 100-inch Telescope in 1924, shortly after he proved the existence of distant galaxies. Photo: Carnegie Observatories/ Huntington Library.

Mount Wilson Observatory News

Angeles Crest Highway is OPEN to Red Box Junction, the turnoff to Mount Wilson Observatory. Beyond that, the Angeles Crest Highway is closed due to a landslide which occurred during the winter, but this does not effect the Observatory. Crews are working to stabilize the hillside and should have it reopened soon.

The grounds, museum, and the 100-inch Telescope viewing gallery are open every day of the year from 10:00 am to 5:00 pm, except when weather or other hazardous conditions warrant a temporary closing. The gates open earlier on weekends at 8:30 am.

The Cosmic Café is open from 10:00 am to 5:00 pm (weekends only), selling sandwiches, drinks, snacks, tour tickets, Adventure Passes (for parking) and souvenirs.

Subscribe to Mount Wilson Observatory News for updates on 2019 concerts, lectures, tours, public telescope nights, and other events. Click here.


Sunday, July 7, come up to the Observatory and enjoy Voices! Music by Danaë Vlasse, Todd Mason, Bruce Babcock, Mark McEnroe, and Anthony Constantino (singers and strings) in the 100-inch dome–the most unusual music venue in Los Angeles! Click on the Concerts page for more information and tickets.

Talks and Telescopes

Saturday, July 13, join us for our third astronomy lecture of the year by Dr. Laura Kerber, a research scientist at NASA’s Jet Propulsion Laboratory in Pasadena. She is the Principal Investigator of the Discovery Mission called Moon Diver, which aims to send an extreme terrain rover into deep caverns on the Moon in order to understand the Solar System’s largest volcanic eruptions. Afterwards there will be a chance for guests to look through the 100-inch telescope! Once everyone has had a look, guests are invited to stay until midnight to look at additional targets. Click on the Talks and Telescopes page for more info and tickets.

2019 Public Ticket Nights

For visitors interested in observing with the big telescopes, we have three “Public Ticket Nights” scheduled in June. These are observing sessions designed for individual ticket holders, rather than the usual group rentals.

The date for the 60-inch Telescope is Friday, June 21 (SOLD OUT, but we have added another 60-inch Public Ticket Night on Friday, July 26) and for the 100-inch Telescope, Saturday, June 22 (SOLD OUT, but we have added another 100-inch Public Ticket Night on Saturday, July 27).

A special “Hyper” Public Ticket Night is scheduled for Saturday, June 29 when you can observe with both of these historic telescopes, switching halfway through the evening (Sold Out, but we have added another of these special sessions with both the 60 & 100-inch on Saturday, August 24).

For details and to reserve a spot please visit the Public Ticket Night page.

Special Behind-the-Scenes Engineering Tours

Limited to ten visitors, these tours, lead by observatory telescope engineers, will take you into areas of the telescope domes and grounds normally off limits to the public. The summer dates have sold out, so we have added more:  Saturday, September 14 (4 spots remaining) and Saturday, October 5 (8 spots remaining).

For more information and tickets please go to the Engineering Tour page.

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

Mount Wilson Observatory’s New Membership Program

The Observatory is launching a membership program for those who would like to join us with ongoing support. By doing so, you get a number of benefits and you help us renew this historic mountaintop, so that it may inspire well into the future. We aim to build a larger community to keep us moving forward with educational STEM programs, undergraduate research, public outreach, ongoing scientific research, and restoration of our 115-year-old observatory.

Please consider becoming a member in 2019. Sign up for the individual membership, family membership, or a higher level named after one of our famous astronomers. Sign up is easy. Click here to go to our membership page.

What’s that Strange Light on Top of Mount Wilson?

Called Sunstar, it is an array of six prisms which take incoming sunlight and refract it, bending the light and spreading it into a spectrum–all the colors of the rainbow. It is mounted near the top of the Observatory’s 150-foot Solar Telescope Tower. With motion controls, it can be remotely directed to project the spectrum to a specific point in the Los Angeles basin. An observer below will see an intense point of light in a single wavelength, shining like a brilliant jewel from the ridgeline of Mount Wilson, 5800 feet above in the San Gabriel Mountains. The prisms can be moved to change the color of light an observer sees, or the observer can walk in one direction or another to change the color. In this case, the observer is actually walking across a giant spectrum some 250 yards long. While still very bright, at the great distances involved, it is perfectly safe to look at a single wavelength of sunlight. For more information and a schedule, go to our Sunstar page.

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.

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, June 18th, 2019 at 9:05am
Important development posted today by @MtWilsonObs on their @facebook feed with implications for the long-term survival of several historic U.S. observatories. These places need legally protected status, and this is an encouraging step in that direction. 🔭 MtWilsonObs photo
Tuesday, May 21st, 2019 at 6:34am
Wilson! 👋🏐🌊😉 @MtWilsonObs was once home for the biggest telescopes and a destination for the world's best scientists 🥼🔭 Read on for why and how you can visit the LA icon🌟 MtWilsonObs photo