Fig. 5 :   PMAS Fiber Spectrograph Optical Design
                top: collimator (fiber coupling onto first lens shown in magnified insert)
                lower right: camera
               (Note that plane of the slit is shown rotated by 90 degrees)

Some properties of the design:
 

  •         collimator and camera fully-dioptric, optimized systems
  •         96mm fiber slit (accomodates 2x256 100um fibers)
  •         telecentric pseudo slit
  •         immersion coupling of fibers to collimator
  •         collimator f=450mm, f/3 with 10 degree field
  •         collimated beam diameter 150mm
  •         reflective grating 154mm x 206mm
  •         camera f=270mm, f/1.5, 12 degree field, 180mm pupil
  •         fully corrected between 350nm and 900nm
  •         mean 100% spot concentration within 20um diameter, max. 26um
  •         mean 80% spot concentration within 15um diameter, max. 24um
  •         compact lens groups, few air-glass interfaces, reduced reflected light
  •         low-curvature surfaces (fabrication, AR-coating)
  •         1 aspheric, exclusively conic surfaces
  •         max. lens diameter 200mm
  •         standard Schott glasses and CaF2 in available blank sizes

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    Last update August 14, 2002  by  M. Roth