TIRSPEC

TIFR Near Infrared Spectrometer and Imager

(1 - 2.5 micron)


Last Updated: 8 September 2014

TIFR Near Infrared Spectrometer and Imager (TIRSPEC) is mounted on 2-m Himalayan Chandra Telescope (HCT) IAO, Hanle, Ladakh, India. It covers wavelength from 1 to 2.5 micron, for near-infrared medium resolution spectroscopy as well as imaging. TIRSPEC was developed in collaboration with Mauna Kea Infrared (MKIR), Hawaii.

Detector array in the instrument is 1024x1024 Hawaii-1 array. With 0.3 arcsec per pixel resolution, the instrument provides a Field of View (FoV) of 307 x 307 arcsec2 in imaging mode. Spectroscopy mode gives a wavelength coverage from 1 micron to 2.5 micron with resolution of ~1200. Apart from single order mode to cover 1.02-1.20 micron, 1.21-1.48 micron, 1.49-1.78 micron and 2.04-2.35 micron, cross disperse modes are also available to provide simultaneous wavelength coverage of 1.02-1.49 micron and also 1.50-2.45 micron.

Exposure Time Calculator
Sky Field View
Object Visibility Observatory:
[ 78.9641 32.77944 4500 +5.5 ]

Instrument is operated remotely from CREST, IIA, Hoskote, Bangalore.

For HCT time proposal submission, visit IAO proposal page.

TIRSPEC User's Manual : PDF

Winter Notice : Avoid using Cal mirror when ambient temperature at Hanle drops below -15 C.

Instrument Overview

Imaging Details

Spectroscopy Details

Detector Characteristics

Reduction Software


TIRSPEC mounted on HCT on 20th June 2013

Instrument Overview


Wavelength Range 1 to 2.5 micron
Detector 1kx1k Hawaii-1 array
Array Size 1024 x 1024
Pixel Size 18 micron
Pixel Scale 0.3 arcsec/pixel
Field of View 307 x 307 arcsec2
Spectral resolution ~1200
Minimum Exposure 0.9 sec[1]
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Imaging Details


Broad Band Photometric filters

Filter Band pass (micron)
J 1.17 - 1.33
H 1.49 - 1.78
K-short 1.99 - 2.30

Narrow Band Photometric filters

Filter Central Wavelength(micron) Band Width (%)
Methane off 1.584 3.6 %
[Fe II] 1.645 1.6 %
Methane on 1.654 4.0 %
H2 (1-0) 2.1239 2.0 %
Br Gamma 2.166 0.98 %
K-Cont 2.273 1.73 %
CO (2-0) 2.287 1.33 %
Filter Scans are also available in ascii format : Zipped

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Spectroscopy Details


Resolution : ~1200

Single Order Mode

Order Wavelength Range (micron)
Y 1.02 - 1.20
J 1.21 - 1.48
H 1.49 - 1.78
K 2.04 - 2.35

Cross Disperse Mode

X Disp Order Wavelength Range (micron)
YJ 1.02 - 1.49
HK 1.50 - 1.84 & 1.95 - 2.45

Available Slits

Slit Width (arcsec) Length (arcsec)
S1 1" 50"
S2 1.48" 50"
S3 1.97" 50"
S4 2.96" 50"
S5 7.92" 50"
L1 1" 300"
L2 1.48" 300"
L3 1.97" 300"
L4 2.96" 300"
L5 7.92" 300"
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Detector Characteristics


Read Noise 4.3 ADU[2]
Dark Current 0.032 ADU/sec[3]
Gain ~5 e/ADU
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Reduction Software


Zip of python scripts : Version 0.2 (for latest version, download latest nightly tar-ball below)

Github repository for latest nightly tar-ball version : TIRSPEC

See Wiki page for instructions on how to run pipeline : Data Pipeline Wiki

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Argon spectral line identification charts are available here and here.

IRAF line list is available here.

More materials on telluric lines etc are available here.

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The authors using TIRSPEC data are requested to acknowledge the use of TIFR Near Infrared Spectrometer and Imager (TIRSPEC) in their acknowledgements.

For any queries please contact Devendra K. Ojha or J. P. Ninan.

Reference papers:
1) TIFR Near Infrared Spectrometer and Imager (TIRSPEC) (Instrument Overview) [PDF]
2) TIFR Near Infrared Spectrometer and Imager (TIRSPEC) (Instrument Overview, Calibration and Pipeline) [PDF].

Footnotes:

[1] Shorter exposures are possible in subarray mode.

[2] Due to our up-the-ramp readout mode, actual readout noise in final image is much smaller than this single frame readout noise.

[3] First few seconds, dark current is high and falls of exponentially. The value quoted is dark current after 30 seconds of exposure.