The Design and On-sky Results of the Prototype of a Low-Resolution Spectrograph for the Thai National Telescope

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Jitsupa Paenoi*
Christophe Buisset
Kajpanya Suwansukho
Wichit Sirichote
Piyamas Choochalerm
Suparerk Aukkaravittayapun
Griangsak Thummasorn
Surin Ngernsujja
Anuphong Inpun
Pimol Kaewsamoeta
Suchinno Kanthum
Apichat Leckngam
Wayne Orchiston
Krittapas Chaniworawit
Saran Poshyajinda
Boonrucksar Soonthornthum

Abstract

The objectives of the research project presented in this paper are to design and develop a Low Resolution Spectrograph for the 2.4 m Thai National Telescope.The Low Resolution Spectrograph will deliver a spectrum in the spectral range (440 -740 nm), with a resolution of R approximately equals to 1,000 at the central wavelength, λc, of 600 nm, while observing through a slit with a width of 0.9 arcsecond wide (in long-slit mode) or during slit-less observations. The Low Resolution Spectrograph was designed to have a total weight of less than 20 kg and a maximum displacement due to gravity of less than 6 µm during a 360° rotation of the instrument cube. We have installed a prototype of the Low Resolution Spectrograph on the Thai National Telescope in December 2018. We have tested its performance on stellar objects during a one-night observing run.  During these observations, we calibrated the instrument using a Thorium-Argon spectral calibration lamp and a Tungsten lamp and recorded the spectrum of the planetary nebula NGC 2392 in both slit-less and long-slit modes.  We measured a spectral resolution of 800-1,300 over the wavelength range 440-740nm, thus demonstrating that the on-sky performance of the prototype was in agreement with the theoretical specifications.


 


Keywords: low resolution spectrograph; long-slit spectroscopy; slitless spectroscopy; opto-mechanical design; Thai National Telescope


*Corresponding author: Tel :083-0112900
E-mail: [email protected]

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Original Research Articles

References

Dhillon, V.S., Marsh, T.R., Atkinson, D.C., Bezawada, N., Bours, M.C.P., Copperwheat, C.M., Gamble, T., Hardy, L.K., Hickman, R.D.H., Irawati, P., Ives, D.J., Kerry, P., Leckngam, A., Littlefair, S.P., McLay, S.A., O’Brien, K., Peacocke, P.T., Poshyachinda, S., Richichi, A., Soonthornthum, B. and Vick. A., 2014. ULTRASPEC: a high speed imaging photometer on the 2.4-m Thai National Telescope. Monthly Notices of the Royal Astronomical Society, 4009-4021.

Buisset, C., Deboos, A., Lépine, T., Poshyachinda,S., and Soonthornthum, B., 2016. Design and performance estimate of a focal reducer for the 2.3 m Thai National Telescope. Optics Express, 1416-1430.

Buisset, C., Poshyachinda, S., Soonthornthum, Prasit, B.A., Alagao, M.A., Choochalerm, P., Wanajaroen, W., Lépine, T., Rabbia, Y., Aukkaravittayapun, S., Leckngam, A., Thummasorn, G., S. Ngernsujja, S., Inpan, A., Kaewsamoeta, P., Lhospice, E., Meemon, P., Artsang, P., Suwansukho, K., Sirichote, W. and Paenoi, J., 2018. Activity status and future plans for the Optical Laboratory of the National Astronomical Research Institute of Thailand. Proceedings of the Third International Conference on Photonics Solutions, 10714. ICPS2017.SPIE.

Dassault Systèmes Solidworks Corp., 1997. SolidWorks. USA 25.0.0.5021.

Nagasawa, D., Marshall, J., DePoy, D., and Mondrik, N., 2014. Conceptual design of a low resolution spectrograph for the Astronomical Observatory of C´ordoba. Ground-based and Airborne Instrumentation for Astronomy V, SPIE 9147.

Ammler-von Eiff, M., Sebastian, D., Guenther, E., Stecklum, B. and Cabrera, J., 2015. The power of low-resolution spectroscopy: On the spectral classification of planet candidates in the ground-based CoRoT follow-up. Astronomische Nachrichten 336(2), 134-144.

Shelyak, Ins., 2006. Thorium-Argon bulb. [online] Available at: https://www.shelyak.com/description-eshel/?lang=en

Wu, C., Li, J., Chang, Z., Lin, C., Hu, J. and Ip, W., 2001. Chemical Abundances of the Planetary Nebulae NGC 2392 and NGC 3242. ASPC, 246, 339.