NSSDCA ID: 1993-058C-02
Mission Name: ORFEUS-SPAS IThe Berkeley Extreme and Far-UV Spectrometer (BEFS) was also known as the Extreme Ultraviolet (EUV) Spectrometer. BEFS operated from 39 - 120 nm, however most observations were conducted in the 90 - 120 nm range. The instrument was designed to provide high-resolution (lambda/5000) spectroscopy of point sources.
Light coming into the ORFEUS 1-m telescope fell onto BEFS when a movable collimator mirror is moved out of the beam. When the mirror was in the beam, light was directed to the Tubingen Ultraviolet Echelle Spectrometer (TUES). Four diffraction gratings dispersed a unique sub-bandpass across one of two spectral detectors near the focal plane of the spectrometer. To maximize resolution and minimize astigmatism, spherical optics with mechanically ruled varied line-spacing in a non-Rowland mounting was used. The BEFS instrument was altered for the second flight (on ORFEUS-SPAS II) by over-coating two of the four diffraction gratings with silicon carbide and modifying the detector electronics to improve the imaging at high count rates.
BEFS, on ORFEUS-SPAS I, obtained Far-UV spectra of about 75 objects. The second flight on ORFEUS-SPAS II resulted in spectra of about 105 objects. EUV spectra were obtained for a subset of targets.
Questions and comments about this experiment can be directed to: Coordinated Request and User Support Office
Name | Role | Original Affiliation | |
---|---|---|---|
Dr. Mark V. Hurwitz | Principal Investigator | University of California, Berkeley | markh@ssl.berkeley.edu |