presentation - Center for Adaptive Optics

							IRIS Telescope Camera
       Kimberly Bott
       Institute for Astronomy
       Mentor: Klaus Hodapp

       Home Institution: University of Hawaii
         at Hilo
       2008 Center for Adaptive Optics
         Akamai Internship
               • Infrared Imaging Survey
                 System (near IR)
Introduction   • Telescope fabrication in
                 Germany
               • Camera fabrication in
                 US
               • IRIS site: Cerro
                 Armazones Observatory
                 in Chile
               • Telescope Goals
                  – Occultation
                  – Variations in reflection
                    nebulae
               • Camera Goals
                  – Effective IR camera
                  – Correct for spherical
                    aberrations
Infrared Camera
         • Cryostat interior to vacuum
            – Why a cryostat?
         • Three components
            – Designed mounting
            – Designed and fabricated
              vacuum casing
            – Learned to fabricate on
              cryostat piece
            – Goals
                • Be lightweight, balanced
                  and strong
                • Allow extra volume for
                  cryostat piece
Infrared Camera
         • Cryostat interior to vacuum
            – Why a cryostat?
         • Three components
            – Designed mounting
            – Designed and fabricated
              vacuum casing
            – Learned to fabricate on
              cryostat piece
            – Goals
                • Be lightweight, balanced
                  and strong
                • Allow extra volume for
                  cryostat piece
Infrared Camera
         • Cryostat interior to vacuum
            – Why a cryostat?
         • Three components
            – Designed mounting
            – Designed and fabricated
              vacuum casing
            – Learned to fabricate on
              cryostat piece
            – Goals
                • Be lightweight, balanced
                  and strong
                • Allow extra volume for
                  cryostat piece
Infrared Camera
         • Cryostat interior to vacuum
            – Why a cryostat?
         • Three components
            – Designed mounting
            – Designed and fabricated
              vacuum casing
            – Learned to fabricate on
              cryostat piece
            – Goals
                • Be lightweight, balanced
                  and strong
                • Allow extra volume for
                  cryostat piece
Testing the Camera’s Existing
           Cryostat
               • Test vacuum
               • Inject liquid nitrogen
                 into cryostat
                  – Monitored weight of
                    camera to determine
                    holding time
                  – Improve holding time
                  – Retest with new
                    pieces
Design of Mounting Piece

             • Designed as strong
               connection between
               camera and
               telescope
Vacuum Casing Design
          • AutoCAD drawing
          • Connection between
            existing casing and
            large mounting
            piece
          • Allowing for an
            effective vacuum
            – Smooth to reduce
              dust/oil presence
            – Lower emissivity
        Fabricating the Part
• Used lathe to aid
  other intern with
  small cryostat piece
• Began work on own
  part
  – Required improvising
    due to unusual size
    and an octagonal
    end
          Testing the Part



• Assembled
• Achieved near
  perfect vacuum
     Filter Wheel Electronics
• 7 IR filters on large
  gear
• Driven by stepper
  motor
• Located with a Hall
  Effect Sensor
• Controlled through
  computer (program
  in C)
     Electronics
• Replaced
  connections
  – Female electronics
    to male
  – Female to the
    stepper motor and
    the Hall Effect
    sensor
      Electronics Testing and
              Results
• Tested connections
  with multimeter
• Tested ensemble,
  ran program to
  begin locating filters
   – Did not align
   – Fixed number of
     teeth in C program
   – Still an issue finding
     the magnet
               Conclusions
Mounting piece:
   accurate design
Vacuum casing:
   effective vacuum
   which does hold
Filter wheel electronics:
   good connections but
   improper alignment
   not due to tooth
   number
       Acknowledgements and
             Sources
• The Akamai Internship Program, funded by the Center for
  Adaptive Optics through its National Science Foundation
  Science and Technology Center grant (#AST-987683)
• Institute for Astronomy
• Dr. Klaus Hodapp
• Richard Shelton

• “The Infrared Imaging Survey (IRIS) System”, Hodapp et al.
• “Cryostat Design and Construction at the IRTF”, Toomey et al.
• http://uigi.com/nitrogen.html
         Additional Links
• http://www.magnet.fsu.edu/education/tut
  orials/java/halleffect/index.html