DIMM (Differential Image Motion Monitor /  Atmospheric Seeing Monitor)

  • Measures seeing parameters using Differential Image Motion technique
  • Operates with the images in focus on the detector
  • Images separated with optical wedge
  • Reimaging optical system places filters and aperture stops in parallel light
  • Filter wheel allows measurements in multiple pass bands
  • Up to 6 filters may be used
  • Up to 6 aperture/wedge configurations may be used
  • Convenient focal plane position with independent focus adjustment
  • Invar spaced optical elements to minimize focus shift with temperature
  • Full control of the CCD camera including subaperture downloading, integration time, and binning
  • Performs autoguiding and star centering functions
  • Robotic operation including star selection, control of the telescope, and control of the shelter
  • Flexible system due to the general purpose filter and aperture wheels
  • Performs sky brightness, atmospheric transmission, and extinction coefficients measurements