This is image is of the 200-inch Hale Telescope at the Palomar Observatory, located in north San Diego County, California which is owned and operated by the California Institute of Technology.

This image is of the Crab Nebula in visible light photographed by the Hale Observatory optical telescope in 1959. The faint object at the center had been identified as a pulsar and is thought to be the remains of the original star. It had been observed as a pulsar in visible light, radio wave, x-rays, and gamma-rays.

This image taken with the Palomar Observatory Hale Telescope, 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.

These two images show HD 157728, a nearby star 1.5 times larger than the sun. Project 1640 uses new technology on the Palomar Observatory 200-inch Hale telescope near San Diego, Calif., to spot planets.

Shown here is an identical copy of the Deep Space Optical Communications, or DSOC, superconducting nanowire single-photon detector that is coupled to the 200-inch (5.1-meter) Hale Telescope located at Caltech's Palomar Observatory in San Diego County, California. Built by the Microdevices Laboratory at NASA's Jet Propulsion Laboratory in Southern California, the detector is designed to receive near-infrared laser signals from the DSOC flight transceiver traveling with NASA's Psyche mission in deep space as a part of the technology demonstration. DSOC will test key technologies that could enable high-bandwidth optical, or laser, communications from Mars distances. Bolted to the side of the spacecraft and operating for the first two years of Psyche's journey to the asteroid of the same name, the DSOC flight laser transceiver will transmit high-rate data to Caltech's Palomar Observatory in San Diego County, California, which houses the 200-inch (5.1-meter) Hale Telescope. The downlink detector converts optical signals to electrical signals, which can be processed and decoded. The detector is designed to be both sensitive enough to detect single photons (quantum particles of light) and able to detect many photons arriving all at once. At its farthest point during the technology demonstration's operations period, the transceiver will be up to 240 million miles (390 million kilometers) away, meaning that by the time its weak laser pulses arrive at Earth, the detector will need to efficiently detect a trickle of single photons. But when the spacecraft is closer to Earth and the flight transceiver is delivering its highest bit rate to Palomar, the detector is capable of detecting very high numbers of photons without becoming overwhelmed. Because data is encoded in the timing of the laser pulses, the detector must also be able to determine the time of a photon's arrival with a precision of 100 picoseconds (one picosecond is one trillionth of a second). To sense single photons, the detector must be in a superconducting state (when electrical current flows with zero resistance), so it is cryogenically cooled to less than minus 458 degrees Fahrenheit (or 1 Kelvin), which is close to absolute zero, or the lowest temperature possible. A photon absorbed in the detector disrupts its superconducting state, creating a measurable electrical pulse as current leaves the detector. DSOC is the latest in a series of optical communication technology demonstrations funded by NASA's Technology Demonstrations Missions (TDM) program and the agency's Space Communications and Navigation (SCaN) program. JPL, a division of Caltech in Pasadena, California, manages DSOC for TDM within NASA's Space Technology Mission Directorate and SCaN within the agency's Space Operations Mission Directorate. https://photojournal.jpl.nasa.gov/catalog/PIA26141

In this infrared photograph, the Optical Communications Telescope Laboratory (OCTL) at NASA Jet Propulsion Laboratory's Table Mountain Facility near Wrightwood, California, beams its eight-laser beacon (at a total power of 1.4 kilowatts) to the Deep Space Optical Communications (DSOC) flight laser transceiver aboard NASA's Psyche spacecraft. The photo was taken on June 2, 2025, when Psyche was about 143 million miles (230 million kilometers) from Earth. The faint purple crescent just left of center and near the laser beam is a lens flare caused by a bright light (out of frame) reflecting inside the camera lens. As the experiment's ground laser transmitter, OCTL transmits at an infrared wavelength of 1,064 nanometers from its 3.3-foot-aperture (1-meter) telescope. The telescope can also receive faint infrared photons (at a wavelength of 1,550 nanometers) from the 4-watt flight laser transceiver on Psyche. Neither infrared wavelength is easily absorbed or scattered by Earth's atmosphere, making both ideal for deep space optical communications. To receive the most distant signals from Psyche, the project enlisted the powerful 200-inch-aperture (5-meter) Hale Telescope at Caltech's Palomar Observatory in San Diego County, California, as its primary downlink station, which provided adequate light-collecting area to capture the faintest photons. Those photons were then directed to a cryogenically cooled superconducting high-efficiency detector array at the observatory where the information encoded in the photons could be processed. Managed by JPL, DSOC was designed to demonstrate that data encoded in laser photons could be reliably transmitted, received, and then decoded after traveling millions of miles from Earth out to Mars distances. Nearly two years after launching aboard the agency's Psyche mission in 2023, the demonstration completed its 65th and final "pass" on Sept. 2, 2025, sending a laser signal to Psyche and receiving the return signal from 218 million miles (350 million kilometers) away. https://photojournal.jpl.nasa.gov/catalog/PIA26661

This infrared photograph shows the uplink laser beacon for NASA's Deep Space Optical Communications (DSOC) experiment beaming into the night sky from the Optical Communications Telescope Laboratory (OCTL) at NASA Jet Propulsion Laboratory's Table Mountain Facility near Wrightwood, California. Attached to the agency's Psyche spacecraft, the DSOC flight laser transceiver can receive and send data from Earth in encoded photons. As the experiment's ground laser transmitter, OCTL transmits at an infrared wavelength of 1,064 nanometers from its 3.3-foot-aperture (1-meter) telescope. The telescope can also receive faint infrared photons (at a wavelength of 1,550 nanometers) from the 4-watt flight laser transceiver on Psyche. Neither infrared wavelength is easily absorbed or scattered by Earth's atmosphere, making both ideal for deep space optical communications. To receive the most distant signals from Psyche, the project enlisted the powerful 200-inch-aperture (5-meter) Hale Telescope at Caltech's Palomar Observatory in San Diego County, California, as its primary downlink station, which provided adequate light-collecting area to capture the faintest photons. Those photons were then directed to a cryogenically cooled superconducting high-efficiency detector array at the observatory where the information encoded in the photons could be processed. Managed by JPL, DSOC was designed to demonstrate that data encoded in laser photons could be reliably transmitted, received, and then decoded after traveling millions of miles from Earth out to Mars distances. Nearly two years after launching aboard the agency's Psyche mission in 2023, the demonstration completed its 65th and final "pass" on Sept. 2, 2025, sending a laser signal to Psyche and receiving the return signal from 218 million miles (350 million kilometers) away. https://photojournal.jpl.nasa.gov/catalog/PIA26662

Shown here is a prototype of the Deep Space Optical Communications, or DSOC, ground receiver detector built by the Microdevices Laboratory at NASA's Jet Propulsion Laboratory in Southern California. The prototype superconducting nanowire single-photon detector was used by JPL technologists to help develop the detector that – from a station on Earth – will receive near-infrared laser signals from the DSOC flight transceiver traveling with NASA's Psyche mission in deep space. DSOC will test key technologies that could enable high-bandwidth optical, or laser, communications from Mars distances. Bolted to the side of the spacecraft and operating for the first two years of Psyche's journey to the asteroid of the same name, the DSOC flight laser transceiver will transmit high-rate data to Caltech's Palomar Observatory in San Diego County, California, which houses the 200-inch (5.1-meter) Hale Telescope. The downlink detector converts optical signals to electrical signals, which can be processed and decoded. The detector is designed to be both sensitive enough to detect single photons (quantum particles of light) and able to detect many photons arriving all at once. At its farthest point during the technology demonstration's operations period, the transceiver will be up to 240 million miles (390 million kilometers) away, meaning that by the time its weak laser pulses arrive at Earth, the detector will need to efficiently detect a trickle of single photons. But when the spacecraft is closer to Earth and the flight transceiver is delivering its highest bit rate to Palomar, the detector is capable of detecting very high numbers of photons without becoming overwhelmed. Because data is encoded in the timing of the laser pulses, the detector must also be able to determine the time of a photon's arrival with a precision of 100 picoseconds (one picosecond is one trillionth of a second). DSOC is the latest in a series of optical communication technology demonstrations funded by NASA's Technology Demonstrations Missions (TDM) program and the agency's Space Communications and Navigation (SCaN) program. JPL, a division of Caltech in Pasadena, California, manages DSOC for TDM within NASA's Space Technology Mission Directorate and SCaN within the agency's Space Operations Mission Directorate. https://photojournal.jpl.nasa.gov/catalog/PIA25840