Tag: Keck

In the Shutter

Inside the Keck 2 Lower Shutter
The top chamber inside the Keck 2 lower shutter
I am slowly becoming an expert in domes.

Seven hundred tons of steel and aluminum, thirty meters diameter. The dome represents a huge piece of machinery critical to the operation of the observatory.

Controlling everything is a PLC, a programmable logic controller, twenty year old technology from another era. Operation is critical, if the dome or shutter fail at the wrong time the telescope could be left exposed to the elements causing untold damage.

Despite, or perhaps because of, their huge mass the domes move with stately grace. I never seem to tire of hitting the button and listening to the rumble, of riding the huge structure as it smoothly rotates.

Every time something breaks it is a chance to learn. In this case it is an inclinometer, a simple angle measurement sensor that allows the system to read out the position of the shutter. Tests from the control panel show that it is simply not talking, I will have to get at the device itself, deep inside the structure of the shutter.

I feared that accessing the inclinometer would be difficult. The reality was somewhat easier, just drop the lower shutter all the way down, and climb into a hatch at the top.

Inside the first chamber is found much of the cabling and the inclinometer. There are even a few lights available so I am not working in the dark. Still, it is a bit eerie to be working inside a big aluminum box, a box that moves.

Cosmic Web Imager Coming to Keck

Caltech press release…

Caltech astronomers have taken unprecedented images of the intergalactic medium (IGM)—the diffuse gas that connects galaxies throughout the universe—with the Cosmic Web Imager, an instrument designed and built at Caltech. Until now, the structure of the IGM has mostly been a matter for theoretical speculation. However, with observations from the Cosmic Web Imager, deployed on the Hale 200-inch telescope at Palomar Observatory, astronomers are obtaining our first three-dimensional pictures of the IGM. The Cosmic Web Imager will make possible a new understanding of galactic and intergalactic dynamics, and it has already detected one possible spiral-galaxy-in-the-making that is three times the size of our Milky Way.

Lyman Alpha Blob
Comparison of Lyman alpha blob observed with Cosmic Web Imager and a simulation of the cosmic web based on theoretical predictions.
Credit: Christopher Martin, Robert Hurt
The Cosmic Web Imager was conceived and developed by Caltech professor of physics Christopher Martin. “I’ve been thinking about the intergalactic medium since I was a graduate student,” says Martin. “Not only does it comprise most of the normal matter in the universe, it is also the medium in which galaxies form and grow.”

Since the late 1980s and early 1990s, theoreticians have predicted that primordial gas from the Big Bang is not spread uniformly throughout space, but is instead distributed in channels that span galaxies and flow between them. This “cosmic web”—the IGM—is a network of smaller and larger filaments crisscrossing one another across the vastness of space and back through time to an era when galaxies were first forming and stars were being produced at a rapid rate.

Martin describes the diffuse gas of the IGM as “dim matter,” to distinguish it from the bright matter of stars and galaxies, and the dark matter and energy that compose most of the universe. Though you might not think so on a bright sunny day or even a starlit night, fully 96 percent of the mass and energy in the universe is dark energy and dark matter (first inferred by Caltech’s Fritz Zwicky in the 1930s), whose existence we know of only due to its effects on the remaining 4 percent that we can see: normal matter. Of this 4 percent that is normal matter, only one-quarter is made up of stars and galaxies, the bright objects that light our night sky. The remainder, which amounts to only about 3 percent of everything in the universe, is the IGM.

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First Potentially Habitable Earth-Sized Planet Confirmed by Keck and Gemini Observatories

The first Earth-sized exoplanet orbiting within the habitable zone of another star has been confirmed by observations with both the W. M. Keck Observatory and the Gemini Observatory. The initial discovery, made by the Kepler Space Telescope, is one of a handful of smaller planets found by Kepler and verified using large ground-based telescopes.

Kepler-186f
The artist’s concept depicts Kepler-186f, the first validated Earth-size planet orbiting a distant star in the habitable zone. Credit NASA AMES/SETI Institute/JPL-CalTech
“What makes this finding particularly compelling is that this Earth-sized planet, one of five orbiting this star, which is cooler than the Sun, resides in a temperate region where water could exist in liquid form,” says Elisa Quintana of the SETI Institute and NASA Ames Research Center who led the paper published in the current issue of the journal Science. The region in which this planet orbits its star is called the habitable zone, as it is thought that life would most likely form on planets with liquid water.

Steve Howell, Kepler’s Project Scientist and a co-author on the paper, adds that neither Kepler (nor any telescope) is currently able to directly spot an exoplanet of this size and proximity to its host star. “However, what we can do is eliminate essentially all other possibilities so that the validity of these planets is really the only viable option.”

With such a small host star, the team employed a technique that eliminated the possibility that either a background star or a stellar companion could be mimicking what Kepler detected. To do this, the team obtained extremely high spatial resolution observations from the eight-meter Gemini North telescope on Mauna Kea in Hawai`i using a technique called speckle imaging, as well as adaptive optics (AO) observations from the ten-meter Keck II telescope, Gemini’s neighbor on Mauna Kea. Together, these data allowed the team to rule out sources close enough to the star’s line-of-sight to confound the Kepler evidence, and conclude that Kepler’s detected signal has to be from a small planet transiting its host star.

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