From The W.M. Keck Observatory: “NASA Releases New Webb and W. M. Keck Observatory Images of Saturn’s Moon Titan”

W.M. Keck Observatory two ten meter telescopes operated by California Institute of Technology(US) and The University of California(US), at Mauna Kea Observatory, Hawai’i, altitude 4,207 m (13,802 ft). Credit: Caltech.

Keck Laser Guide Star Adaptive Optics on two 10 meter Keck Observatory telescopes, Mauna Kea Hawai’i, altitude 4,207 m (13,802 ft).

Mauna Kea Observatories Hawai’i altitude 4,213 m (13,822 ft).

From The W.M. Keck Observatory

Mari-Ela Chock
Communications Officer
W. M. Keck Observatory
(808) 554-0567

Titan, as seen by the Keck 2 telescope on Mauna Kea, Hawai’i, is the only moon in the solar system with a dense atmosphere and the only world besides earth that has standing bodies of liquid rivers, lakes, and seas.
Credit: Judy Schmidt/ W. M. Keck Observatory.

From space with Webb and on the ground with the W. M. Keck Observatory on Mauna Kea, Hawaiʻi, astronomers have tag-teamed to capture a set of extraordinary images revealing large clouds in the northern hemisphere of Saturn’s largest moon, Titan.

“Detecting clouds is exciting because it validates long-held predictions from computer models about Titan’s climate, that clouds would form readily in the mid-northern hemisphere during its late summertime when the surface is warmed by the Sun,” said Conor Nixon, Principal Investigator of the Guaranteed Time Observation (GTO) program 1251 team at NASA’s Goddard Space Flight Center.

As part of their investigation of Titan’s atmosphere and climate, Nixon’s team used Webb’s Near-Infrared Camera (NIRCam) to observe the moon during the first week of November.

After seeing the clouds near Kraken Mare, the largest known liquid sea of methane on the surface of Titan, they immediately contacted the Keck Titan Observing Team to request follow-up observations.

Near-infrared Images of Saturn’s moon Titan, as seen by Webb on November 4, 2022 (left), followed by Keck Observatory’s NIRC2 [below] instrument paired with adaptive optics on November 6, 2022 (middle) and November 7, 2022 (right). Credit: NASA/STScI/W. M. Keck Observatory/Judy Schmidt.

“We were concerned that the clouds would be gone when we looked at Titan a day later with Keck, but to our delight there were clouds at the same positions on subsequent observing nights, looking like they had changed in shape,” said Imke de Pater, emeritus professor of astronomy at the University of California-Berkeley, who leads the Keck Titan Observing Team.

Using Keck Observatory’s second generation Near-Infrared Camera (NIRC2) in combination with the Keck II Telescope’s adaptive optics system [above], de Pater and her team observed one of Titan’s clouds rotating into and another cloud either dissipating or moving out of Earth’s field of view due to Titan’s rotation. Tracking the clouds’ motions are important because they give insight into how air is flowing within Titan’s atmosphere.

Evolution of clouds on Titan over 30 hours between Nov. 4 and Nov. 6 captured by Webb (top) and Keck Observatory (bottom). Titan’s trailing hemisphere seen here is rotating from left (dawn) to right (evening) as seen from Earth and the Sun. Cloud A appears to be rotating into view while Cloud B appears to be either dissipating or moving behind Titan’s limb. Clouds are not long-lasting on Titan or Earth, so those seen on November 4 may not be the same as those seen on November 6. Credit: NASA/STScI/Keck Observatory/Judy Schmidt.

Nixon and de Pater’s teams will continue to analyze the fresh data, with more Webb observations planned.

As the only moon in the solar system with a dense atmosphere, as well as the only place besides Earth to have present-day liquid rivers, lakes, and oceans, astronomers hope to deepen their understanding of Titan’s spectacular environment.

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The W. M. Keck Observatory operates the largest, most scientifically productive telescopes on Earth. The two, 10-meter optical/infrared telescopes on the summit of Mauna Kea on the Island of Hawaii feature a suite of advanced instruments including imagers, multi-object spectrographs, high-resolution spectrographs, integral-field spectrometer and world-leading laser guide star adaptive optics systems. Keck Observatory is a private 501(c) 3 non-profit organization and a scientific partnership of the California Institute of Technology, the University of California and NASA.

Today Keck Observatory is supported by both public funding sources and private philanthropy. As a 501(c)3, the organization is managed by The California Association for Research in Astronomy(CARA), whose Board of Directors includes representatives from the California Institute of Technologyand the University of California with liaisons to the board from The National Aeronautics and Space Agency and the Keck Foundation.

Keck UCal


Keck 1

HIRES – The largest and most mechanically complex of the Keck’s main instruments, the High Resolution Echelle Spectrometer breaks up incoming starlight into its component colors to measure the precise intensity of each of thousands of color channels. Its spectral capabilities have resulted in many breakthrough discoveries, such as the detection of planets outside our solar system and direct evidence for a model of the Big Bang theory.

Keck High-Resolution Echelle Spectrometer (HIRES), at the Keck I telescope.
LRIS – The Low Resolution Imaging Spectrograph is a faint-light instrument capable of taking spectra and images of the most distant known objects in the universe. The instrument is equipped with a red arm and a blue arm to explore stellar populations of distant galaxies, active galactic nuclei, galactic clusters, and quasars.

UCO Keck LRIS on Keck 1.

VISIBLE BAND (0.3-1.0 Micron)

MOSFIRE – The Multi-Object Spectrograph for Infrared Exploration gathers thousands of spectra from objects spanning a variety of distances, environments and physical conditions. What makes this huge, vacuum-cryogenic instrument unique is its ability to select up to 46 individual objects in the field of view and then record the infrared spectrum of all 46 objects simultaneously. When a new field is selected, a robotic mechanism inside the vacuum chamber reconfigures the distribution of tiny slits in the focal plane in under six minutes. Eight years in the making with First Light in 2012, MOSFIRE’s early performance results range from the discovery of ultra-cool, nearby substellar mass objects, to the detection of oxygen in young galaxies only 2 billion years after the Big Bang.

Keck/MOSFIRE on Keck 1.

OSIRIS – The OH-Suppressing Infrared Imaging Spectrograph is a near-infrared spectrograph for use with the Keck I adaptive optics system. OSIRIS takes spectra in a small field of view to provide a series of images at different wavelengths. The instrument allows astronomers to ignore wavelengths where the Earth’s atmosphere shines brightly due to emission from OH (hydroxl) molecules, thus allowing the detection of objects 10 times fainter than previously available.
Keck OSIRIS on Keck 1.

Keck 2

DEIMOS – The Deep Extragalactic Imaging Multi-Object Spectrograph is the most advanced optical spectrograph in the world, capable of gathering spectra from 130 galaxies or more in a single exposure. In ‘Mega Mask’ mode, DEIMOS can take spectra of more than 1,200 objects at once, using a special narrow-band filter.

Keck/DEIMOS on Keck 2.

NIRSPEC – The Near Infrared Spectrometer studies very high redshift radio galaxies, the motions and types of stars located near the Galactic Center, the nature of brown dwarfs, the nuclear regions of dusty starburst galaxies, active galactic nuclei, interstellar chemistry, stellar physics, and solar-system science.

NIRSPEC on Keck 2.

ESI – The Echellette Spectrograph and Imager captures high-resolution spectra of very faint galaxies and quasars ranging from the blue to the infrared in a single exposure. It is a multimode instrument that allows users to switch among three modes during a night. It has produced some of the best non-AO images at the Observatory.

KECK Echellette Spectrograph and Imager (ESI).

KCWI – The Keck Cosmic Web Imager is designed to provide visible band, integral field spectroscopy with moderate to high spectral resolution, various fields of view and image resolution formats and excellent sky-subtraction. The astronomical seeing and large aperture of the telescope enables studies of the connection between galaxies and the gas in their dark matter halos, stellar relics, star clusters and lensed galaxies.

Keck Cosmic Web Imager on Keck 2 schematic.

Keck Cosmic Web Imager on Keck 2.

NEAR-INFRARED (1-5 Micron)

ADAPTIVE OPTICS – Adaptive optics senses and compensates for the atmospheric distortions of incoming starlight up to 1,000 times per second. This results in an improvement in image quality on fairly bright astronomical targets by a factor 10 to 20.

LASER GUIDE STAR ADAPTIVE OPTICS [pictured above] – The Keck Laser Guide Star expands the range of available targets for study with both the Keck I and Keck II adaptive optics systems. They use sodium lasers to excite sodium atoms that naturally exist in the atmosphere 90 km (55 miles) above the Earth’s surface. The laser creates an “artificial star” that allows the Keck adaptive optics system to observe 70-80 percent of the targets in the sky, compared to the 1 percent accessible without the laser.

NIRC-2/AO – The second generation Near Infrared Camera works with the Keck Adaptive Optics system to produce the highest-resolution ground-based images and spectroscopy in the 1-5 micron range. Typical programs include mapping surface features on solar system bodies, searching for planets around other stars, and analyzing the morphology of remote galaxies.

Keck NIRC2 Camera on Keck 2.
The Near Infrared Echellette Spectrograph (NIRES) is a prism cross-dispersed near-infrared spectrograph built at the California Institute of Technology by a team led by Chief Instrument Scientist Keith Matthews and Prof. Tom Soifer. Commissioned in 2018, NIRES covers a large wavelength range at moderate spectral resolution for use on the Keck II telescope and observes extremely faint red objects found with the Spitzer and WISE infrared space telescopes, as well as brown dwarfs, high-redshift galaxies, and quasars.

Future Instrumentation

KCRM – The Keck Cosmic Reionization Mapper will complete the Keck Cosmic Web Imager (KCWI), the world’s most capable spectroscopic imager. The design for KCWI includes two separate channels to detect light in the blue and the red portions of the visible wavelength spectrum. KCWI-Blue was commissioned and started routine science observations in September 2017. The red channel of KCWI is KCRM; a powerful addition that will open a window for new discoveries at high redshifts.

KCRM – Keck Cosmic Reionization Mapper KCRM on Keck 2.

KPF – The Keck Planet Finder (KPF) will be the most advanced spectrometer of its kind in the world. The instrument is a fiber-fed high-resolution, two-channel cross-dispersed echelle spectrometer for the visible wavelengths and is designed for the Keck II telescope. KPF allows precise measurements of the mass-density relationship in Earth-like exoplanets, which will help astronomers identify planets around other stars that are capable of supporting life.

KPF Keck Planet Finder on Keck 2.