EXES instrument

Echelon-Cross- Echelle Spectrograph (EXES)


EXES Chapter of the Cycle 9 Observer's Handbook
EXES Chapter of the Cycle 8 Observer's Handbook

Principal Investigator Class Science Instrument
Principal Investigator:
Matthew J. Richter 
Dept. of Physics, UC Davis, 1 Shields Ave., Davis, CA 95616
Instrument Team Website

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 HandbookBe sure that you are referencing the correct version of the handbook!

The EXES Guest Observer (GO) Data Handbook describes EXES data products, processing steps, calibration procedures, and known issues.

Primary Reference:
Use when citing SOFIA/EXES results.

"EXES: The Echelon-cross-echelle Spectrograph for SOFIA", Richter, et al., 2018, JAI, 7, 1840013.
DOI: 10.1142/S2251171718400135; ADS Bibliographic Code: 2018JAI.....740013R

Additional References:

"Status of the Echelon-cross-Echelle Spectrograph for SOFIA", Richter et al., 2010, ProcSPIE 7735, 77356Q.
DOI: 10.1117/12.856515 [pdf]

"Development and future use of the echelon-cross-echelle spectrograph on SOFIA"
Richter et al., 2006, ProcSPIE 6269, 62691H.
DOI: 10.1117/12.670559 [pdf]

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