The Observatory is temporarily closed due to the winter storms & Angeles Crest Highway is closed at Clear Creek intersection, due to a landslide that is blocking the road east of Red Box Road which connects the Observatory to the Angeles Crest Highway (see above).

Be aware of winter conditions in the mountains before driving up. After winter storms, the upper roads may have lingering patches of black ice, which can contribute to an accident. This is especially true on Red Box Road from the Angeles Crest Highway (2) up to the Observatory. This road is on the north side of the mountain and in places receives little sun to melt ice. Please drive it with caution.

The Observatory maintenance crew works hard to keep the grounds dug out after snowstorms, but be aware that there will be patches of ice, so please be extremely careful walking around the Observatory. To avoid this hazard completely, come up in warmer weather.

We are looking for an animal-lover to adopt Mount Wilson’s cat. He was first spotted roaming around the mountaintop in November 2017. Originally he received the unimaginative name “Mountain Cat,” until someone suggested the name Winkie, as he only has one eye.  When Winkie first arrived, he would not come close to anyone. A member of the CHARA telescope array staff started putting food for him under a trailer and after a week he started eating it. After another week, Winkie would let people pet him and after another, he would come inside the trailer. He lets just about everyone hold him now. This is one tough cat to survive as long as he has on the mountain. We would like to find him a loving home! If you might be interested in adopting Winkie, send an email to:

Winter Announcements

Our popular Weekend Public Tours have ended for the year and will resume March 30, 2019. With advance notice, private tours are available all year, but may be cancelled due to weather conditions in the winter months. For more information on private tours clicker here. To schedule a private tour, send us an email at:

The Cosmic Café has closed for the season and will reopen on March 30, 2019. The grounds, museum, and 100-inch Telescope viewing gallery, however, will remain open every day of the year, except when snow and ice, or other hazardous conditions warrant a temporary closing. The gates will be open from 10:00 am to 4:00 pm during the winter season.

We will not be taking 60 & 100-inch telescope reservations for 2019 until March 1st, 2019, when our reservation calendar will be reopened.

2019 Training for New Mount Wilson Observatory Docents!

Interested in giving tours of the most productive astronomical observatory in history? Mount Wilson Observatory will start a new docent training program this Spring. The training course will consist of four consecutive Saturday sessions, starting at 10:00 a.m. and ending at 4:00 p.m. The dates are March 23 and 30, and April 6 and 13. The exact location of the sessions is yet to be determined, but they will be either at Mount Wilson Observatory or in Pasadena. Applicants will be notified.

Docent volunteers are vital to the public outreach programs at Mount Wilson Observatory, and Mount Wilson Institute (the nonprofit which operates the Observatory) is always interested in receiving applications from potential docents. No in-depth knowledge of astronomy is required, and all the necessary training is provided to new docents taking on outreach responsibilities. We are looking for enthusiastic communicators who want to tell the wonderful story of Mount Wilson’s scientific heritage. Click here for more details and the application form.

 Mount Wilson Observatory has a wish list of items and services that would really help us in maintaining and improving our facilities. Check out the list by clicking here. It’s a great way to help in lieu of money. Such “in-kind” donations to the Observatory are also tax-deductible! We are a 501 (c) (3) nonprofit. We receive no regular funding from government or institutions, so all donations that lower our expenses are greatly appreciated!


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 114-year-old campus.

We are just five years away from the centennial of Mount Wilson’s most well-known discovery, astronomer Edwin Hubble’s determination that all the faint “spiral nebulae” are really distant galaxies. We have many things we want to do to prepare for this grand event in 2023. Our goal is to bring the Observatory up to a more sustainable level by this time, so that we can properly showcase the incredible science accomplished on this spectacular mountain above Los Angeles.

As the 2018 draws to a close, please consider joining us with a membership to get the new program off to an amazing start. 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 new membership page.

We are a 501(c) non-profit, so your membership is tax-deductible. As always, end-of-year donations are also welcome, which are also quick and easy via our website or mail: Mount Wilson Insitute, P.O. Box 94146, Pasadena, CA 91109. Our largely volunteer organization receives no regular support from government or institutions.

End the year on a high note with an inaugural membership to 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


Sunstar is an art/science collaboration by Liliane Lijn and John Vallerga

A closeup of the Sunstar prism array, mounted near the top of the 150-foot Solar Telescope Tower.

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

During the last year or so we have been asked this question many times. We have been testing a special art installation called Sunstar, created and owned by artist Liliane Lijn and astrophysicist John Vallerga. It is on loan to Mount Wilson Observatory, and can now be seen from a number of locations around the area. For a schedule go to our Sunstar page.

An array of six prisms, Sunstar takes incoming sunlight and refracts 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.

Why are we doing this? For the wonder of it, the pure delight at seeing brilliant spectral colors derived directly from the Sun, the source of light that gives us life.

For the science of it. Mount Wilson Observatory was the first built specifically to do spectroscopy, to capture light from the Sun and other stars and spread it out into all its wavelengths, so that all the information it contains could be deciphered. And this art installation is useful in our STEM outreach program for local schools — it generates intrigue in the spectrum and teaches spectroscopy, a powerful tool used in almost all sciences and many industries. Students in an open area can walk through the entire spectrum.

Finally, Sunstar draws attention to Mount Wilson Observatory, and is a fitting way to celebrate our founder George Ellery Hale’s 150th anniversary. He was a solar astronomer, visionary, and institution builder, who influenced many aspects of the development of  Pasadena from the moment he selected Mount Wilson as the site for the Carnegie Institution’s Observatory.

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

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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Wednesday, February 6th, 2019 at 7:50am
Astronomers have recently found that the Milky Way is actually twisted after studying the pulsing behavior of Cepheids and using the research to create a 3D map. Read more: #ScienceDiscovery
Friday, February 1st, 2019 at 1:38pm
#ReplayToday: Jan. 31, 1931 (Mount Wilson Observatory, California)
Dr. Albert #Einstein, left, poses with fellow scientists after visiting the world's largest telescope at #MountWilsonObservatory in the #SanGabrielMountains near #Pasadena. (AP Photo) @MtWilsonObs
MtWilsonObs photo
Saturday, January 19th, 2019 at 12:45pm
We are in need of new docents for our upcoming 2019 season! If you’re interested (or know anyone who is), check out the information posted on our webpage. Docent training will begin on March 23, 2019