PARAS-2 precision radial velocimeter: optical and mechanical design of a fiber-fed high resolution spectrograph under vacuum and temperature control

• DOI: 10.1117/12.2313055
• Publication Date: 2018-07-20T18:12:30Z
• Authors: Nitesh Thapa; Rishikesh Sharma; Abhijit G. Chakra...; Kapil Kumar; Prasad J.S.S. V. ...; Arpita Roy
• Keywords: High resolution Spectroscopy; Grism; Exoplanets; 0103 physical sciences; Echelle; 530; 7. Clean energy; 01 natural sciences; 520

We present here the optical and mechanical design of a fiber-fed High-resolution spectrograph at resolution (R) = 100,000 which will be under vacuum (0.001 to 0.005 mbar) temperature controlled environment 25C ± 0.001C. The attached our upcoming new PRL 2.5m aperture telescope Gurushikar, Mount Abu, Rajasthan, India. is named PARAS-2 after successful operation PARAS (PARAS-1) with existing 1.2m Abu since 2012 summer. (PARAS-2) operating in range 380nm 690nm wavelength single shot using Grism as Cross Disperser, R4 Echelle blaze angle 76degrees, pupil diameter 200 mm. use combination octagonal circular fibers along double scrambler simultaneous calibration for getting down RV precision 50cm/s or better (< 50cm/s). Minimum 30% time reserved exoplanet work on when it becomes operational early 2020. overall efficiency whole (Echelle, M1, M2, FM, Grism, Camera lens system, Dewar window) excluding fiber expected 22.5% - 28% 4% 8% including fiber, fibertelescope interface losses.