We present spectrograph design details and initial radial velocity results from the PRL optical fiber-fed high-resolution cross-dispersed echelle spectrograph ( PARAS ) , which has recently been commissioned at the Mt Abu 1.2 m telescope , in India .
Data obtained as part of the post-commissioning tests with PARAS show velocity precision better than 2 m s ^ { -1 } over a period of several months on bright RV standard stars .
For observations of \sigma Dra we report 1.7 m s ^ { -1 } precision for a period of seven months and 2.1 m s ^ { -1 } for HD 9407 over a period of 2 months .
PARAS is capable of a single-shot spectral coverage of 3800 - 9500Å at a resolution of \sim 67,000 .
The RV results were obtained between 3800Å and 6900Å using simultaneous wavelength calibration with a Thorium-Argon ( ThAr ) hollow cathode lamp .
The spectrograph is maintained under stable conditions of temperature with a precision of 0.01 - 0.02 ^ { \circ } C ( rms ) at 25.55 ^ { \circ } C , and enclosed in a vacuum vessel at pressure of 0.1 \pm 0.03 mbar .
The blaze peak efficiency of the spectrograph between 5000Å and 6500Å , including the detector , is \sim 30 \% ; and \sim 25 % with the fiber transmission .
The total efficiency , including spectrograph , fiber transmission , focal ratio degradation ( FRD ) , and telescope ( with 81 % reflectivity ) is \sim 7 % in the same wavelength region on a clear night with good seeing conditions .
The stable point spread function ( PSF ) , environmental control , existence of a simultaneous calibration fiber , and availability of observing time make PARAS attractive for a variety of exoplanetary and stellar astrophysics projects .
Future plans include testing of octagonal fibers for further scrambling of light , and extensive calibration over the entire wavelength range up to 9500Å using Thorium-Neon ( ThNe ) or Uranium-Neon ( UNe ) spectral lamps .
Thus , we demonstrate how such highly stabilized instruments , even on small aperture telescopes , can contribute significantly to the ongoing radial velocity searches for low-mass planets around bright stars .