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

Introduction Infrared Imaging Survey System (near IR) 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 ) 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.

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