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