Hawaii-Built Infrared Instrument For World’s Largest Solar Telescope Catches Its First Rays

A first-light image from CryoNIRSP. It delivers two spectra simultaneously with opposite polarizations (the left and right panels above). This image shows light from near the edge of the Sun spread out horizontally in wavelength, near the wavelength of a prominent absorption line of Calcium. Image Credit: UH Institute for Astronomy

April 12, 2017 – The Daniel K. Inouye Solar Telescope (DKIST), currently under construction on Haleakala, Maui, is expected to start observing the Sun in 2020. When it does, it will rely on two complex infrared instruments being built by the University of Hawaii Institute for Astronomy (IfA). Their goal is to measure the Sun’s weak magnetic field.

The first of these to be completed is called the Cryogenic Near-Infrared Spectropolarimeter (CryoNIRSP). In a major milestone, it took its first look at the Sun from the laboratories at the IfA’s Advanced Technology Research Center on Maui. The instrument design was lead by Dr. Don Mickey, now retired from the IfA.

The CryoNIRSP instrument exposed in its clean-room environment undergoing tests. From left to right: Drs. Andre Fehlmann, Jeff Kuhn, and Isabelle Scholl. Image Credit: UH Institute for Astronomy

Instrument scientist Dr. Andre Fehlmann said, “These first trial images from CryoNIRSP in visible light show that the innovative optical design will be sensitive enough to see the Sun’s magnetism.” Project manager Dr. Isabelle Scholl added that “CryoNIRSP is being completed in the Pukalani, Maui labs and will be delivered to the summit of Haleakala within a year, when the telescope can accept our instrument.”

CryoNIRSP weighs about two tons, and was constructed on a budget of $6M provided by the National Science Foundation. The project leader, Dr. Jeff Kuhn said, “As soon as DKIST becomes operational, this will become the workhorse that local scientists and visitors from all over the world will use to trace the Sun’s coronal magnetism and its influence on the Earth.”

Monitoring space weather is crucial as our society increasingly relies on technology that is susceptible to damage from these large space events. Scientists have successfully measured the solar magnetic field strength close to the Sun’s surface, where the field is relatively strong. Higher in the solar atmosphere, in a layer called the corona, the magnetic field weakens to the strength of a refrigerator magnet. DKIST will be able to detect this weak field and usher in a new era of solar physics.

NSF funds DKIST through a cooperative agreement with the Association of Universities for Research in Astronomy (AURA).

The DKIST Data Center will be located in Boulder, Colorado, where data will be shipped via optical fiber directly from Hawaii.