page_title: Hale Telescope
section_title: Direct imaging of exoplanets
hierarchical_section_title: Hale Telescope / Observations and research / Direct imaging of exoplanets
caption_attribution_description: English: This image shows the light from three planets orbiting a star 120 light-years away. The planets' star, called HR8799, is located at the spot marked with an "X." This picture was taken using a small, 1.5-meter (4.9-foot) portion of the Palomar Observatory's Hale Telescope, north of San Diego, Calif. This is the first time a picture of planets beyond our solar system has been captured using a telescope with a modest-sized mirror -- previous images were taken using larger telescopes. The three planets, called HR8799b, c and d, are thought to be gas giants like Jupiter, but more massive. They orbit their host star at roughly 24, 38 and 68 times the distance between our Earth and sun, respectively (Jupiter resides at about 5 times the Earth-sun distance).
context_page_description: The Hale Telescope is a 200-inch, f/3.3 reflecting telescope at the Palomar Observatory in California, US, named after astronomer George Ellery Hale. With funding from the Rockefeller Foundation in 1928, he orchestrated the planning, design, and construction of the observatory, but with the project ending up taking 20 years he did not live to see its commissioning. The Hale was groundbreaking for its time, with double the diameter of the second-largest telescope, and pioneered many new technologies in telescope mount design and in the design and fabrication of its large aluminum coated "honeycomb" low thermal expansion Pyrex mirror. It was completed in 1949 and is still in active use.
  The Hale Telescope represented the technological limit in building large optical telescopes for over 30 years. It was the largest telescope in the world from its construction in 1949 until the Russian BTA-6 was built in 1976, and the second largest until the construction of the Keck Observatory Keck 1 in 1993.
context_section_description: Up until the year 2010, telescopes could only directly image exoplanets under exceptional circumstances. Specifically, it is easier to obtain images when the planet is especially large (considerably larger than Jupiter), widely separated from its parent star, and hot so that it emits intense infrared radiation. However, in 2010 a team from NASA's Jet Propulsion Laboratory demonstrated that a vortex coronagraph could enable small scopes to directly image planets. They did this by imaging the previously imaged HR 8799 planets using just a 1.5 m portion of the Hale Telescope.
caption: Direct image of exoplanets around the star HR8799 using a vortex coronagraph on a 1.5m portion of the Hale Telescope
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