1890 |
1891 | Throop University - the precursor to Caltech - established |
1900 | 1902 | Carnegie Institution of Washington established |
| 1904 | George Ellery Hale becomes the first Director of Mt. Wilson Observatory | |
| Mt. Wilson Solar Observatory funded by the Carnegie Institution of Washington | ||
| 1905 | Snow Solar Telescope on Mt. Wilson takes its first solar spectrum | |
| 1908 | Mt. Wilson 60 foot Solar Tower built | |
| Mt. Wilson 60 inch Telescope completed; the largest telescope in the world at the time | ||
| George Ellery Hale discovers magnetic fields in sunspots |
Featured images from 1900s-1910s
1910 | 1912 | 150 foot Solar Tower completed at Mt. Wilson |
| 1917 | 100 inch Hooker Telescope completed at Mt. Wilson; the largest telescope in the world from 1917-1949 | |
| 1919 | Stellar interferometer added to 100 inch telescope | |
| Harlow Shapley discovered shape of our Milky Way galaxy |
1920 | 1920 | Throop College of Technology is renamed the California Institute of Technology |
| Harlow Shapley-Heber Curtis "Great Debate" on the size of the universe | ||
| 1921 | First measurement of the size of another star: Betelgeuse | |
| 1923 | Robert A. Millikan - Chairman of Caltech Executive Council (1921-1945) - wins the Nobel Prize for Physics | |
| Edwin Hubble discovers Andromeda, M31, is a galaxy | ||
| 1924 | Edwin Hubble shows many other galaxies exist beyond our own Milky Way | |
| Pasadena Junior College - now known as Pasadena City College (PCC) - is established on the Pasadena High School Campus | ||
| Edwin Hubble shows many other galaxies exist beyond our own Milky Way | ||
| 1928 | Grant from the Rockefeller Foundation for the fabrication of a 200 inch reflecting telescope | |
| 1929 | Edwin Hubble discovers the universe is expanding and measures the size of the known universe |
Featured images from 1920s-1930s
1930 | 1931 | Einstein visit to Caltech; Einstein was a visiting professor at Caltech during the winter terms of 1931-33 |
| Opening of the new observatory building at Pasadena City College (PCC) - dedicated by Albert Einstein | ||
| 1933 | Caltech Astronomer Fritz Zwicky finds the first evidence for ‘dark matter’ at Mt. Wilson | |
| 1936 | 18 inch Schmidt telescope installed at Palomar Mountain | |
| Student rocket experiments conducted at Arroyo Seco; these early experiments ultimately led to the establishment of JPL |
1940 | 1944 | Walter Baade at Mt. Wilson Observatory first recognizes different populations of stars |
| Jet Propulsion Laboratory officially named | ||
| 1948 | The Palomar 200 inch (5.1 meter) telescope dedicated - largest telescope in the world until 1976 | |
| 48 inch (1.2 meter) wide-field Schmidt telescope takes its first official photograph |
Featured images from 1940s-1950s
1950 | 1952 | By identifying two classes of "Cepheid variable" stars, astronomer Walter Baade refines the extragalactic distance scale - the estimated size of the known universe doubles |
| 1958 | Allan Sandage, working at Palomar Observatory, publishes first accurate estimate of the rate of expansion of the universe, and updates the "Hubble constant" | |
| Launch of Explorer 1, first US satellite and first-ever orbital science experiment | ||
| JPL transferred from Army to NASA | ||
| Caltech's Owens Valley Radio Observatory (OVRO) becomes operational |
1960 | 1960 | Beginning of the Mariner program to explore the planets. 10 missions launched through the early 1970s |
| Helioseismology studies of the Sun begin at the Mt. Wilson 60 foot Tower telescope | ||
| 1962 | Mariner 2 flyby of Venus | |
| 1963 | Caltech astronomer Maarten Schmidt discovers a new type of object - quasars - using the Palomar 200 inch telescope | |
| 1964 | Ranger 7 is the first US mission to the Moon | |
| 1965 | Planetarium is completed at PCC | |
| 1966 | Surveyor 1 is the first US lander on the Moon | |
| 1969 | Establishment of Las Campanas Observatory (LCO) in Chile by Carnegie Observatories |
Featured images from 1960s-1970s
1970 | 1970 | Caltech's 60 inch telescope completed and begins observations at Palomar Observatory |
| 1971 | Carnegie Observatories begins operations with the Henrietta Swope telescope - 1 meter (40 inch) reflector - at Cerro Las Campanas in Chile | |
| 1973 | Over 120 supernovae discovered using the Palomar Schmidt telescopes by Caltech astronomer Fritz Zwicky | |
| Palomar Planet-Crossing Asteroid Survey initiated by Eleanor Helin | ||
| 1975 | Launch of Viking 1 mission to Mars | |
| Viking 2 launch | ||
| 1976 | Viking 1 lands on Mars | |
| Viking 2 lands on Mars | ||
| 1977 | Carnegies Observatories begins operations of the Irénée du Pont 2.5 meter (100 inch) telescope at Las Campanas, Chile | |
| Voyager 1 & 2 launched | ||
| 1979 | Kidspace Children's Museum founded at the California Institute of Technology |
1980 | 1980 | Voyager 1 at Saturn |
| The Planetary Report magazine established | ||
| Planetary Society founded by Carl Sagan, Bruce Murray, and Lou Friedman | ||
| 1981 | Discovery of giant voids and the cosmic web by Carnegie astronomers Steve Shectman, Alan Dressler and others | |
| 1984 | Laser Interferometer Gravitational-Wave Observatory (LIGO) founded as a Caltech/MIT project | |
| 1985 | IPAC is established at Caltech, initially to support the Infrared Astronomical Satellite (IRAS) extended mission | |
| Beginning of construction of the Keck I 10 meter telescope on Maunakea, Hawaii | ||
| 1986 | Non-profit Mount Wilson Institute assumes management of mountain | |
| 1987 | Discovery of Supernova 1987A (SN 1987A) at Las Campanas Observatory by Ian Shelton and Oscar Duhalde | |
| Caltech Submillimeter Observatory (CSO) has first light on Maunakea, Hawaii with an image of M82 | ||
| 1989 | Voyager 2 at Neptune | |
| Galileo mission to Jupiter launched |
Featured images from 1980s - 1990s
1990 | 1990 | NASA/IPAC Extragalactic Database (NED) founded |
| Keck I telescope on Maunakea begins operation | ||
| 1991 | Galileo spacecraft flies by asteroids Gaspra and Ida | |
| 1992 | Mt. Wilson 60 inch telescope outfitted with adaptive optics | |
| Mt. Wilson 100 inch Hooker Telescope reopened | ||
| 1993 | Infrared Science Archive (IRSA) established at IPAC | |
| WFPC2 camera, built by JPL, installed on the Hubble Space Telescope | ||
| 1994 | LIGO site construction begins at Hanford, Washington | |
| 1995 | LIGO site construction begins at Livingston, Louisiana | |
| IPAC begins US support of ESA's Infrared Observatory in Space (ISO) | ||
| Mt. Wilson 100 inch Hooker Telescope outfitted with adaptive optics | ||
| Galileo spacecraft begins orbiting Jupiter | ||
| 1996 | Keck II telescope begins operations on Mauna Kea | |
| Mars Pathfinder launched | ||
| 1997 | IPAC begins analysis, processing and archiving for 2MASS, first high-resolution all-digital sky survey | |
| IPAC is assigned the Spitzer Science Center in support of NASA's Spitzer Space Telescope | ||
| 100 inch Hooker Telescope added laser guide star system | ||
| Pathfinder lands on Mars | ||
| Cassini - a mission to Saturn - launched | ||
| 1998 | Deep Space 1, a test for ion propulsion, launched | |
| 1999 | First detection of a transiting exoplanet around another star (HD 209458) | |
| Stardust - a comet sample return mission - launched |
2000 | 2000 | Shuttle Radar Topography Mission maps Earth from the Space Shuttle Endeavour |
| First light for the Walter Baade telescope - the first of the twin 6.5 meter Magellan telescopes | ||
| 2001 | Mars Odyssey launched | |
| Genesis - a mission to return a sample of the solar wind - launched | ||
| Deep Space 1 arrives at comet Borrelly | ||
| Landon Clay telescope - the second of the twin 6.5 meter Magellan telescopes - begins science operations | ||
| First episode of Planetary Radio, a weekly space science radio show/podcast from The Planetary Society | ||
| 2003 | Galaxy Evolution Explorer (GALEX) mission launched | |
| Carnegie astronomers determine that supermassive black holes are found in nuclei of all galaxies | ||
| Mars Exploration Rovers - Spirit and Opportunity - launched | ||
| Foundation of the nonprofit Thirty Meter Telescope (TMT) Observatory Corporation | ||
| NASA's Spitzer Space Telescope - Hubble's infrared-light sibling - launched | ||
| 2004 | Spirit & Opportunity land on Mars | |
| Center for High Angular Resolution Astronomy (CHARA) interferometer completed on Mt. Wilson | ||
| Stardust arrives at comet Wild 2 | ||
| First GMT primary mirror is cast at Steward Observatory Mirror Lab (now Richard F. Caris Mirror Lab) | ||
| Genesis returns solar wind sample to Earth, the first material collected and returned from beyond the Moon | ||
| 2005 | Caltech astronomers using Keck determine the Andromeda galaxy is 3x larger than previously thought | |
| Acceleration of the expansion of the Universe discovered | ||
| Cosmos Award for Public Presentation of Science established by The Planetary Society | ||
| Caltech astronomer Mike Brown discovers Eris, an object more distant and massive than Pluto | ||
| Deep Impact launched | ||
| Huygens lands on Titan | ||
| Spitzer Space Telescope detects the first light ever seen from planets orbiting other stars | ||
| Spitzer Space Telescope makes first weather map of an exoplanet | ||
| Cosmos 1, The Planetary Society's first solar sail spacecraft, launched but fails to reach orbit | ||
| Deep Impact probe collides with comet Tempel 1 | ||
| Deep Impact & Spitzer announce 'ingredients' of Tempel 1 | ||
| 2006 | GMT Conceptual Design Review held | |
| Stardust returns first sample of a comet to Earth | ||
| Discovery of Eris prompts astronomers to demote Pluto to "Dwarf Planet" status | ||
| 2007 | Palomar Transient Factory (PTF) automated survey begins | |
| Dawn mission to Vesta and Ceres launched | ||
| 2008 | GMT partners sign Founders Agreement and form GMTO Corporation | |
| 2009 | US Planck Science Data Center at IPAC co-releases its first maps of the cosmic microwave background | |
| The Planetary Society announces LightSail project, a plan to sail a spacecraft on sunlight alone | ||
| The Planetary Society develops Living Interplanetary Flight Experiment (LIFE) | ||
| Astronomers using Keck telescope detect methane on Mars | ||
| Kepler planet-finding mission launched | ||
| Palomar Transient Factory (PTF) detects its first supernova (of thousands to come) | ||
| Launch of Herschel Space Observatory | ||
| Spitzer Warm Mission begins | ||
| Mauna Kea selected as preferred site for TMT | ||
| Spitzer discovers Saturn's largest ring | ||
| Wide-Field Infrared Survey Explorer (WISE) launched | ||
| Wide-Field Infrared Survey Explorer (WISE) satellite data processing & archiving begins at IPAC |
Featured images from 2000s
2010 | 2010 | Large Binocular Telescope Interferometer (LBTI) commissioned to study exoplanetary systems |
| 2011 | Launch of STS-134 Shuttle LIFE experiment | |
| Dawn spacecraft arrives at Vesta | ||
| Herschel Space Observatory discovers oxygen molecules in space | ||
| Mars Curiosity rover launched | ||
| Kepler finds 4500 candidate exoplanets; over 1000 confirmed | ||
| 2012 | GMT site leveled and infrastructure development begun | |
| First two GMT mirrors completed | Launch of the first focusing hard x-ray telescope - NASA's Nuclear Spectroscopic Telescope Array (NuSTAR) mission | |
| Voyager 1 reaches interstellar space | ||
| Curiosity lands on Mars | Discovery of an exoplanet orbiting Alpha Centauri, our closest stellar neighbor | |
| 2013 | NuSTAR helps solve riddle of spinning black holes | |
| 2014 | Large Synoptic Survey Telescope (LSST) Science User Interface and Tools Center assigned to IPAC | |
| Eyepiece viewing commissioned at 100 inch Hooker Telescope, dedicated to public use | ||
| NuSTAR maps radioactivity in supernova remnant for first time | ||
| Formation of TMT International Observatory LLC (TIO) | ||
| 2015 | Dawn spacecraft arrives at the dwarf planet Ceres | |
| Spitzer determines distance to one of the most distant exoplanets known | ||
| Launch of Lightsail 1 - a solar sail spacecraft from The Planetary Society | ||
| LightSail 1 deploys solar sail | ||
| GMT Board announces start of construction | ||
| Spitzer finds 'Buckyball' molecules in space around dead stars | ||
| GMT groundbreaking ceremony at Cerro Las Campanas, Chile | ||
| Hawaii Supreme Court revokes TMT construction permit | ||
| 2016 | LIGO announces the first discovery of strong gravitational waves from a collision of two black holes | |
| TMT initiates detailed studies of alternate sites for the telescope | ||
| Spacecraft Juno enters orbit at Jupiter | ||
| 2017 | JPL's "Interior Exploration using Seismic Investigations, Geodesy and Heat Transport" (InSight) mission lands on Mars | |
| 2018 | The Planetary Society launches LightSail 2 - a solar sail spacecraft | |
| 2019 | The Event Horizon Telescope captures the firsr-ever image of a black hole in galaxy Messier 87 | |
2020 | 2021 | James Webb Space Telescope (JWST) launch |
| NASA's Perseverance rover obtains the first recording of sound on Mars | ||
| 2022 | JWST first light and images released | 2024 | NASA's Europa Clipper is launched to explore Jupiter's icy moon Europa | 2025 | Vera C. Rubin Observatory achieves first light and captures its inaugural image |
| 2026 | Nancy Grace Roman Telescope launch (estimated for 2026) |