- SOFIA Overview
- Proposing & Observing
- Meetings and Events
Echelon-Cross- Echelle Spectrograph (EXES)
EXES operates in the 4.5 – 28.3 μm wavelength region, at high (R ≈ 50,000 – 100,000), medium (R ≈ 5000 – 20,000) and low (R ≈ 1000 – 3000) spectral resolution. The instrument uses a 1024x1024 Si:As detector array. High resolution is provided by an echelon—a coarsely-ruled, steeply-blazed aluminum reflection grating—along with an echelle grating to cross-disperse the spectrum. The echelon can be bypassed so that the echelle acts as the sole dispersive element. This results in single order spectra at medium or low resolution depending on the incident angle.
One of the greatest advantages of SOFIA is its ability to study molecules that are blocked by the Earth's atmosphere. In particular, the high spectral resolution provided by EXES enables the study of molecular hydrogen, water vapor, and methane from sources such as molecular clouds, protoplanetary disks, interstellar shocks, circumstellar shells, and planetary atmospheres.
Examples of EXES scientific observations and summary of specifications: EXES Flyer
Information applicable to the observing cycles can be found in their respective versions of the Observer's Handbook. Be sure that you are referencing the correct version of the handbook!
Use when citing SOFIA/EXES results.