TRISPEC Basic Parameters


Pixel Scale and Field of View

The instrument has four arrays: a SITe 512 x 512 CCD is the detector for imaging and spectrograph for the optical channel, two SBRC InSb 256 x 256 arrays are the detectors for imaging and spectrograph for two infrared channels; and a SITe 512 x 512 CCD is the detector for the slit viewing array on the spectroscopic modes. The fileds of view of three detectors for imaging and spectrograph are almost same, and the pixel scales on the infrared channels are twice the pixel scale on the optical channel. The field of view of the slit-viewing detector is smaller than one of the imaging and spectrograph detectors, and is approximately 0.65 times as one of the imaging and spectrograph detectors. The scales at the slit/mask plane, the field of view, the internal F-ratios, and the pixel scales at several telescopes are the below table.
 
Telescope Focus Scale
at Slit/Mask
(arcsec/mm)
Field
of
View
(arcsec)
Optical Channel Infrared Channels
Internal
F-ratio
Pixel
Scale
(arcsec)
Internal
F-ratio
Pixel
Scale
(arcsec)
Subaru f/12.5 2.27 76 4.1 0.15 2.6 0.30
UKIRT f/36 1.68 56 12.1 0.11 7.6 0.22
UH88 f/10 10.0 334 4.1(*) 0.66 2.6(*) 1.31
f/31 3.30 110 10.3 0.22 6.5 0.43

(*) Since the instrument accepts an f/12.5 beam from telescope, the internal F-ratios are limited to 4.1 on the optical channel and 2.6 on the infrared channels. Then, when the instrument is mounted on UH88 with the f/10 secondary, the effective diameter of the telescope is 1.76m.


Orientation

At UKIRT, TRISPEC is usually mounted on the North port of the ISU. Then, the TRISPEC image display shows (approximately) North down and East to the left (The image display locates first pixel at the upper-left of the image). And, all slits run along a north-south direction (along column on array). Since the instrument has no image rotator, the position angles of the slits are fixed to (approximately) north-south direction.

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Last Modification Date: 2001/05/29
Last Modification Author: Makoto Watanabe <watanabe@z.phys.nagoya-u.ac.jp>