Presentation Open Access
Samra, Jenna; Cheimets, Peter; Guth, Giora
The total solar eclipse of August 21, 2017 offers a unique opportunity for study of the infrared solar corona. The Airborne Infrared Spectrometer (AIR-Spec), currently under development, is an infrared telescope and spectrometer that will search for several magnetically sensitive coronal emission lines between 1.4 and 4 micrometers. This instrument will be the first to observe several of these lines, and the measurement campaign will determine whether any lines may be useful for future direct observations of the coronal magnetic field. AIR-Spec will be mounted on an NSF/NCAR Gulfstream V jet and will observe the eclipse from an altitude greater than 14.9 km, above the bulk of IR-absorbing atmospheric water vapor.
To ensure that the images taken for analysis have adequate spatial resolution, the AIR-Spec line-of-sight must be stabilized to 2 arc-seconds over a 1 second exposure time. Image stabilization is achieved by using a fiber-optic gyroscope to measure aircraft rotation and a fast-steering mirror to adjust the line-of-sight accordingly. The stabilization algorithm runs in a programmable automation controller, which interfaces with the gyroscope and mirror. Software was developed to implement the stabilization algorithm in the controller and to integrate the controller with a user interface, allowing for data display and logging, user guided attitude calibration, and manual control of the fast-steering mirror. This software is currently being used in lab testing and will be operational during test flights in Fall 2016 and Spring 2017 and the eclipse flight in Summer 2017. The current system stabilizes images to 2 arc-seconds in 60 percent of 1 second camera exposures.