Getting CanariCam Ready, Day Four

GTC Observatory
Roque de los Muchachos
La Palma, Canary Islands

Overnight, the hard working compressor finally got the temperature of the infrared detector down to where it needs to be, about 444 degrees below zero. A meeting is held in the morning with the observatory staff to coordinate the many activities that need to occur, some simultaneously, to get CanariCam ready for use on the GTC (Grantecan) telescope. Michiel van der Hoeven, Chief of Operations at the observatory, tells us that the staff stands ready to help get the instrument commissioned.



Now a new enemy is raising its ugly head - bad weather, the bane of every astronomer's existence. A storm is predicted to come through Wednesday, just when it is hoped that the University of Florida team can begin making initial observations. Nothing to do about that but wait and see. Astronomers tell stories of waiting months to get one precious night on a large telescope for a project, only to have that be the one night when it decides to rain, ruining the observations and requiring another multi-month wait for another try.

The observatory staff is already putting on the adaptor plate on the telescope, which will allow CanariCam to be fitted to the telescope's focus. The thick black steel plate, specially designed for CanariCam, weighs over a ton and takes three workers and a crane to get it up to the focus and bolted to the telescope. The segmented mirror (36 separate mirrors), largest in the world, sits on its side in the dome, waiting to be let loose on the skies.



In a room under the dome, six extra mirrors are kept in storage, ready to act as replacements as needed. UF astronomer Chris Packham gives us an up close look at these individual mirrors. Their undersides are covered with intricate motors and pulleys which can slightly bend the shapes of the mirror surfaces, compensating for minor errors and seeing conditions.



Suddenly, at about 12:30, the steady drone of the compressor ceases and everything gets strangely quiet in the lab. The compressor has quit working and the internal temperatures are starting to climb back up. Everyone stops what they're doing, and an intense session of troubleshooting begins. Gregg Bennett, the team engineer, takes the cover off. The compressor tank has overheated. A short? A bad solenoid switch? A helium leak? A replacement compressor is wheeled in, but the detector temperature is already back up to minus 425 degrees F, extremely cold but much too hot for infrared work. A few tweaks later and the old compressor kicks back on. The temperature immediately drops back down to comfortable levels.



Except for the activities of the CanariCam team and staff, the cavernous dome is empty and quiet. One floor below, the control room mainly consists of a maze of computer screens. Here, the dome can be opened and rotated, and the telescope pointed with extreme accuracy. Some of the more precise guiding aspects of the telescope are still being modified, but it is hoped that both the telescope and CanariCam will soon demonstrate that they make a fine pair. That is, if the weather holds up!

Terry Smiljanich

CanariCam Cooldown, Day Three

Roque de los Muchachos Observatory
La Palma, Canary Islands

Minus 340 degrees Fahrenheit and counting. The cryogenic pump has been working for over 55 hours hours now as the temperatures inside CanariCam slowly decline to optimal levels (10K or less at the critical detector and we’re OK). Meanwhile, the vacuum inside CanariCam is being maintained at levels equal to about one ten billionth of the air pressure at sea level.

Observatory staffers ask how it’s coming, as everyone is anticipating mating the CanariCam mid-infrared camera with the 10.4 meter Grantecan telescope. With the gathering power of the huge mirror (composed of 36 separate mirrors all working together as one large mirror), and the sensitivity of the University of Florida instrument, new astronomical discoveries are potentially around the corner.

There is a small “window” in our atmosphere at 10 microns (infrared wavelengths one hundredth of a millimeter in length) where electromagnetic radiation can pierce through the water vapor that blocks most of the infrared. CanariCam’s detector can observe through this window, and with the power of Grantecan will hopefully be able to achieve an angular resolution of up to 0.20 arc seconds. For us non-astronomers, that’s equivalent to being able to see the width of a human hair held 500 feet away). It is thus possible that with CanariCam we may better understand how planetary systems such as our own solar system develop over time.

Perhaps CanariCam will resolve the debris disk surrounding a faint planetary system with sufficient detail to determine whether it includes an asteroid belt similar to our own. If so, we can better understand planetary systems as a whole, rather than just the individual planets that are being discovered on a monthly basis.

This is just one of many projects proposed for CanariCam once it is commissioned. Another proposal, by UF astronomer Jonathan Tan, wants to look at very young stars buried in the dust of the Orion Nebula. CanariCam has unique polarimetric capabilities, allowing an observer to sort out the distribution of magnetic fields as they create polarization in dust particles surrounding a star. With this new tool, the development of protoplanetary disks over time can begin to be mapped out and compared to theoretical predictions.

All of this is a part of the busy astronomical activity going on at the top of this mountain. Practically next door, the 4.2 meter (163 inches) William Herschel Telescope, built in 1987, was at one time the third largest telescope in the world, before being eclipsed by the new generation of 8-10 meter telescopes like Gemini, Keck, and Grantecan. The Herschel was the first to provide evidence of a supermassive black hole, called Sagittarius A, at the center of our own Milky Way galaxy. The Deputy PI on CanariCam, University of Florida's Chris Packham (Charlie Telesco is the Principal Investigator, as Chris hastens to add), once worked with the Herschel, and proudly gave us a tour of this venerable telescope.



The MAGIC I & II instrument, just down slope from Grantecan, consists of twin 17 meter segmented mirrors pointed horizontally and looking for lingering evidence of gamma rays striking the atmosphere that came from supernovae and accretion disks around supermassive black holes. These black holes, from which no light can escape, have incredible masses, from 4 million suns to billions of suns, all crammed within very small spaces very far away. They remain invisible, but the havoc created by their interaction with surrounding matter creates super-energetic rays that can be detected. This June MAGIC detected cosmic rays from a quasar 6 billion light years away. When these rays left their source, our own Sun had not even been born yet).

All the CanariCam team can do today, a quiet Sunday with clear blue skies, is wait and watch the slopes of the cooling curves. Once the proper temperatures are reached, however, organized chaos will descend as everyone runs through final checks and the large instrument is lifted up to the observing platform and the telescope silently moves toward a distant target. You can already sense the excitement that will run high in the control room adjacent to the telescope when that happens.

Terry Smiljanich

At the Gran Telescopio Canarias, Day Two

With a few clouds drifting through the collection of white domes at the top of the Roque de los Muchachos peak, we drive up to the Grantecan to see how the cooldown is progressing. Working our way through some tourists visiting the world’s largest telescope, we head for the laboratory, where all through the night the refrigerant pump has been using helium to bring the internal temperature of the CanariCam infrared detector closer to the working target of approximately 8K.

The temperature detectors, monitored through software designed by team member Frank Varosi, show the steady progress of cooling down. The detectors are currently showing temperatures as low as 40K (-388 degrees Fahrenheit), slowly dropping after 25 hours of pumping.

Cold yes, but not nearly cold enough to allow the detector to find and count the few feeble photons making their way to Earth from cold debris surrounding a star 63 light years away, or sneaking through dust surrounding the center of our own Milky Way some 26,000 light years distant. Greg Bennett, the team engineer, adjusts a relief valve, watching the pressure readings, and the pump quietly whines away as the temperature slowly creeps downward.



The air is cool and dry at 7900 feet. Spectacular sunsets are routine here above the clouds. Due to its location, this peak is one of two premier observing sites in the Northern Hemisphere (the other being Mauna Kea in the Hawaiian Islands). The island, La Palma, is the most northeasterly of the Canary Islands, just a few hundred miles from the Moroccan coast of Africa.

The peak, called Roque de los Muchachos, is named after an outcropping of volcanic rocks looking somewhat like tall humans. It perches on the very rim of a huge caldera formed from the collapse of the Taburiente volcano a half million years ago. The caldera is six miles across and almost as deep as the Grand Canyon. From the top, at sunset one can see the shadow of the mountain cast across the Atlantic Ocean, with the island of Tenerife clearly visible.

It is here that the European Northern Observatory operates thirteen world class telescopes, with teams from Great Britain, Italy, Spain, the United States, and other countries, all working on scientific projects to explore the farthest reaches of space and time. In addition to Grantecan, other famous telescopes abound, such as the William Herschel Telescope (4.2 meters), the TNG (Galileo), and “MAGIC,” a twin set of huge 56 foot mirrors pointed horizontally and looking for particle showers caused by cosmic rays.



The University of Florida is a 5% partner in the Grantecan telescope, inaugurated in 2009, and is designing and utilizing instruments such as CanariCam for use on the facility. In return, the Florida team has access to the telescope for its own projects. Because the target is to commission CanariCam on the telescope next week at the Nasmyth focus (one of the observing spots on the telescope), the Florida team has exclusive access to the telescope for a few nights, both to commission the instrument and begin collecting important scientific data. One can detect the envy in the voices of other astronomers during mealtime discussions. “Ah, you're on the Florida team. You have the Nasmyth focus next week!”

CanariCam Commisioning at the GTC

September 18, 2010, La Palma, Canary Islands

An ocean away, on top of a tall mountain overlooking the Atlantic and the clouds far below, we finally arrive at the world’s largest telescope, the Gran Telescopio Canarias (Grantecan). The University of Florida team, led by Professor Charles Telesco, is here to officially commission its new mid-infrared camera, the CanariCam, specially designed to work in conjunction with Grantecan to explore regions of space normally inaccessible to visible light.

Internationally known for its expertise in designing, building and using high end astronomical instrumentation on some of the world’s largest telescopes, the University of Florida will install CanariCam on the business end of the 500 ton telescope facility, which uses a segmented mirror 34 feet across (over twice as large as the iconic Mt. Palomar 200 inch telescope in California). With what amounts to the largest eye on the planet, the heat sensitive CanariCam will be able to peer through obscuring interstellar dust with unprecedented accuracy, looking, for example, at the center of galaxies hiding black holes, or looking for exoplanets (planets outside our own solar system) in the process of forming around young stars.

First,however,the complicated instrument, as large as a coffee table, and hooked to closet-sized electronic cabinets, has to be checked out to make sure it is ready for installation and use. And that can get hairy. In order, for example, for the camera to detect the extremely faint emissions from distant heat sources, it has to eliminate as much as possible the heat being generated closer to home, the camera housing itself and the very telescope it is using. In addition, it has to peer through the heavy humid atmosphere of Earth.

In order to accomplish this, the infrared detector at the heart of the camera must be cooled to around 8 Kelvin (that’s -445 degrees Fahrenheit). But the new two stage cryogenic “coldhead,” which allows it to achieve such frigid temperatures, is giving the team fits. Switching back to an older coldhead unit, everyone is anxiously watching the monitors as the slow process of cooldown is underway. The laborious process should be completed by Sunday, at which time the instrument can be checked out and, if everything goes well, readied for installation on the telescope.

Astronomers from around the world are waiting, their proposals for using the unique instrument dependent upon a successful commissioning. These proposals include new examinations of protoplanetary and debris disks around young stars (potentially letting us observe the formation of new planetary systems), and penetrating the interior of active galactic nuclei, obscured by dust in the visible spectrum.

For an amateur astronomer like me, living temporarily in an astronomical community and working in a laboratory sitting beneath such a magnificent telescope, I keep waiting for someone to wake me up. “What are you doing here?” I hope to document this exciting activity in pictures and in this blog, hopefully giving a sense of being amidst science at the cutting edge. Each day for the next week I will post observations and photos, following the progress of the Florida team, explaining infrared astronomy in further detail, and looking more closely at the capabilities of CanariCam.

Terry Smiljanich

Rosemary Reborn: Students Upgrade the 30" Telescope at Rosemary Hill Observatory

Phase 1 of a student-led project to upgrade the instrument package on the 30-inch Rosemary Hill Observatory telescope is nearly completed.

Led by a Sigma Xi Grant In Aid of Research awarded to UF graduate student Scott Fleming, and working alongside Dr. Francisco Reyes, Amanda Townsend, Dr. Anthony Gonzalez, Dr. John Oliver, Robert Morehead, Nathan De Lee and Dr. Eric Ford, a new SBIG ST8X-ME CCD, a new 10-filter filter wheel, and a new set of Johnson-Cousins filters has been successfully installed.

The ST8X-ME also includes a second built-in detector that allows the CCD to auto-guide itself, maintaining image position and allowing for long integrations and stable sequences of multiple exposures. The new CCD has a significantly larger field of view compared to the previous camera, 15.6 x 10.4 arcminutes. The new camera will be used by undergraduate students to conduct research projects as part of the Observational Techniques class this semester. It will also be used by graduate students and professors to conduct research projects locally.

The attached image is a "first light", three-color image of the M13 globular cluster, observed by Dr. Reyes and Amanda Townsend, and created by Amanda Townsend. No calibration data was taken for this first light image, which is the reason for the noisier-than-usual background.

The quality of this rough image is a sign of great things to come from the new 30-inch instrument package. Better images taken with a full set of calibration data and processing will be shared in the near future after some additional tests are done with the instruments this month.