| Abstract : | We present here the design, development, optical alignment, and calibration results of the PRL second generation fiber-fed high-resolution spectrograph ”PARAS-2,” which is commissioned and attached with the 2.5m telescope at PRL observatory, Mount Abu, Rajasthan, India. It uses the the white pupil design configuration with R4 Echelle grating as diffracting element and Grism as a cross disperser. Post-commissioning data for the Uranium (Ur) calibration lamp shows the resolution R 110000 in a single shot wavelength coverage of 380 nm to 690 nm. The spectrograph is kept inside a temperature and pressure-controlled environment. The temperature is maintained at 22.5+/-0.001 degree Celsius, and the pressure is maintained between 0.001-0.005 mbar. The peak efficiency of the spectrograph alone is 80 percent and 30 percent, including fiber optics losses. Considering the telescope and atmospheric losses, the
effective efficiency of the spectrograph is 8-10 percent. The main science goals of this spectrograph is to discover and study the exoplanets and possible bio-signatures around the fainter target stars of up to 12th magnitude. With the initial calibration results, we claim the radial velocity accuracy of the order of 50cm/sec for brighter sources and 1-2
m/sec for the fainter sources. |
