Hipparcos Payload and Satellite Characteristics

Optics:

     Telescope configuration                All-reflective Schmidt
     Field of view                                      0.9 x 0.9 degrees
     Focal length                                       1400 mm
     Separation between fields            58 degrees
     Diameter of primary mirror            290 mm
     Mirror surface accuracy                 λ/60 rms

Primary Detection System:

      Modulating grid                                2688 slits
      Slit period                                           1.2 arcsec (8.2 micron)
      Detector                                              Image dissector tube
      Photocathode                                   S20
      Sensitive field of view                     38 arcsec diameter
      Spectral range                                  375-750 nm
      Sampling frequency                        1200 Hz

Star Mapper (Tycho) System:

      Modulating grid                                4 slits perpendicular to scan plus 4 slits at ±45 degree inclination
      Detector                                              Photomultiplier tubes
      Photocathode                                    Bialkali
      Spectral range ('B')                          λ_eff = 430 nm, Δλ = 90 nm     
      Spectral range ('V')                          λ_eff = 530 nm, Δλ = 100 nm 
      Sampling frequency                         600 Hz

Satellite Parameters:

       Launch mass                                     1140 kg
       Power requirements                        295 W
       Uplink data rate                                2 kbit/s
       Downlink data rate                           24 kbit/s
       Spin axis inclination to Sun            43 degrees
       Spin rate                                              168.75 arcsec/s

Mission Parameters: