Pointing of HAGAR telescope mirrors
| Autor: | P. U. Kamath, R. J. Britto, G. C. Anupama, S. K. Sharma, F. Gabriel, S. K. Rao, S. K. Duhan, N. Dorji, Tsewang Dorjai, B. S. Acharya, F. Saleem, Dorje Angchuk, T. P. Prabhu, M. Tashi Thsering, G. Srinivasulu, S. S. Upadhya, A. I. D'Souza, V. R. Chitnis, J. Manoharan, P. K. Mahesh, Amit Shukla, P. M. M. Kemkar, B. B. Singh, R. Srinivasan, P. V. Sudersanan, B. K. Nagesh, K. S. Gothe, P. R. Vishwanath, Ramanath Cowsik, Lab Saha |
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| Rok vydání: | 2012 |
| Předmět: |
Physics
business.industry Parabolic reflector Reflecting telescope Astrophysics::High Energy Astrophysical Phenomena Astrophysics::Instrumentation and Methods for Astrophysics Astronomy Astronomy and Astrophysics Active optics Astrophysics::Cosmology and Extragalactic Astrophysics law.invention Telescope Light source Optics Space and Planetary Science law Astrophysics::Solar and Stellar Astrophysics Astrophysics::Earth and Planetary Astrophysics business Cherenkov radiation |
| Zdroj: | Experimental Astronomy. 35:489-506 |
| ISSN: | 1572-9508 0922-6435 |
| Popis: | An array of seven atmospheric Cherenkov telescopes was commissioned at a high altitude site in Hanle in the Ladakh region of the Himalayas. The array called HAGAR has been designed to observe celestial γ-rays of energy >100 GeV. Each telescope is altitude-azimuth mounted and carries seven parabolic mirrors whose optic axes are co-aligned with the telescope axis. The telescopes point and track a celestial source using a PC-based drive control system. Two important issues in positioning of each HAGAR telescope are pointing accuracy of telescope axis and co-alignment of mirrors’ optic axes with the telescope axis. We have adopted a three pronged strategy to address these issues, namely use of pointing models to improve pointing accuracy of the telescopes, RA-DEC scan technique to measure the pointing offsets of the mirrors and mechanical fine-tuning of off-axis mirrors by sighting a distant stationary light source. This paper discusses our efforts in this regard as well as the current status of pointing and monitoring of HAGAR telescopes. |
| Databáze: | OpenAIRE |
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