How Does WIRE Work?

Cassegrain Telescope

This is a diagram of a typical Cassegrain telescope.   Notice how the light enters from the left and is reflected by the primary (concave) mirror to the secondary (convex) mirror.  The secondary mirror then redirects and focuses the light.  The focal point is at the end of the telescope.

Optical Ritchey-Chretien Telescope

  

This is an optical version of a Ritchey-Chretien Telescope (the same type that is used on WIRE).  Note the eyepiece at the focal point in the end of the telescope.

 

 

WIRE Instrument


This is a cutaway image of the WIRE Instrument.  Notice how the light enters from the left and is redirected by the mirrors (shown in brown) as described above.  Infrared light detectors (shown in pink) are located at the focal point.   The cryostat is dual stage and uses solid hydrogen to cool both the detectors and the optics.  The detectors will be cooled to 7 Kelvin (-266° Celsius) by the primary tanks (green).   The optics will be cooled to 14 Kelvin (-259° Celsius) by the secondary tanks (blue).  The reason for this cooling is to keep the instrument from emitting light at wavelengths that would interfere with the survey. 

Also see How Does WIRE Work?

[Next]

Last Updated: 12/2/98