24-10-2012, 01:58 PM
Focus and Tip-Tilt Alignment Procedure for the Enhanced Aerospace Near-Infrared Imaging Spectograph
ABSTRACT
This document describes the procedure used to assess focus of the enhanced Aerospace Near-Infrared Imaging
Spectrograph (NIRIS). NIRIS is a long-slit spectrograph operating from 0.38 micrometers to 2.5 micrometers, but the
procedure is applicable to almost all hypcrspectral imagers. The procedure also assesses the orthogonality of the focal-plane
arrays relative to the optical axis (i.e, tip-tilt=pitch and yaw) and provides information about the rotation of the array about
the optical axis (i.e., roll) as well. These tasks are accomplished by observing an emission line lamp (or any other suitable
wavelength calibration source) at opposite edges of the spectrograph’s F-beam. This procedure requires only the emission
lamp and the hyperspectral imager under test and provides quantitative measurements of the magnitude and direction of focus
error as well as FPA non-orthogonality Procedures for reducing and analyzing the data are included as well.
ABSTRACT
This document describes the procedure used to assess focus of the enhanced Aerospace Near-Infrared Imaging
Spectrograph (NIRIS). NIRIS is a long-slit spectrograph operating from 0.38 micrometers to 2.5 micrometers, but the
procedure is applicable to almost all hypcrspectral imagers. The procedure also assesses the orthogonality of the focal-plane
arrays relative to the optical axis (i.e, tip-tilt=pitch and yaw) and provides information about the rotation of the array about
the optical axis (i.e., roll) as well. These tasks are accomplished by observing an emission line lamp (or any other suitable
wavelength calibration source) at opposite edges of the spectrograph’s F-beam. This procedure requires only the emission
lamp and the hyperspectral imager under test and provides quantitative measurements of the magnitude and direction of focus
error as well as FPA non-orthogonality Procedures for reducing and analyzing the data are included as well.