- Tmt India
The Largest Telescope in Asia with a diameter of 2.3M
Ever since its commissioning in 1986 the 2.3 m aperture Vainu Bappu Telescope has been operated as a National Facility.
The 2.3m telescope is equipped with the fibrefed coude echelle spectrometer.Spectrometer operates in a littrow mode and consists of a six-element collimator-camera system which operates both as a collimator to the input and as a camera to the dispersed output beam. The main dispersing element is a spectrometer that consists of a 408 X 204 mm^2 echelle grating of 52.6 gr/mm with a blaze angle of 70 degree. The input beam size is 150 mm. The dispersed spectrum is recorded on 2k X 4K, 15 micron pixel CCD (read out time is approx 6 min) or a 1K X 1K 24-micron CCD camera with read-out time is around 30 seconds. The star light is fed to the spectrometer from the prime focus of the telescope by an optical fibre. Spectra of resolution R = ~30,000 - 100,000 can be obtained by varying the slit width. Details about the spectrograph are available in Rao et al. 2005, JAPA, 26, 331.
The Prime Focus Imaging Camera is equipped with a 1K X 1K 24-micron CCD camera, with a gain of 5.9 e/ADU and readout noise of 8-9 e. The FOV is 10 X 10 arcmin with a scale of ~ 0.6 arcsec/pixel.