PRL advanced radial-velocity all-sky search (PARAS): An efficient fiber-fed spectrograph for planet searches

Abhijit Chakraborty, Eric Harvey Richardson, Suvrath Mahadevan

Research output: Chapter in Book/Report/Conference proceedingConference contribution

6 Scopus citations


We present here the optical design of an efficient Fiber-fed, Prism Cross-dispersed, Echelle Spectrograph (Resolution ~70,000 @seeing limited ~2arcsecs conditions) which will operate in the wavelength region of 3700A to 8100A. It will be used for extra-solar planets searches down to the precision of 3m/s and as well as for follow-up observations for new transit discoveries. The spectrograph design is such that with a beam size of 100mm (4inch) it should suit the existing 1 to 2m class of telescopes available in India. The fiber-fed spectrograph will be installed with a 1.2m telescope, which is situated at Mt. Abu (5800feet), Rajasthan, India. We estimate the spectrograph to be >30% efficient from the slit to the CCD detector, and up to 15% efficient including sky, telescope, fiber-fed optics etc. We expect to reach the S/N ratio of 70 on a 10mag star for an integration time of 40mins. We aim to achieve 5m/s to 3m/s Radial Velocity accuracies on such a star using the simultaneous ThAr referencing method. Since thermal stability is absolutely necessary to achieve <5m/s RV accuracies, the whole spectrograph is planned to be kept inside a vibration free isolated tank under low vacuum (0.001 mbar) in a thermally isolated room at 28C +/- 0.01C. It should see the first light by the summer of 2009. We are guaranteed at least 120 nights per year for the planet search program, more nights are possible.

Original languageEnglish (US)
Title of host publicationGround-based and Airborne Instrumentation for Astronomy II
StatePublished - 2008
EventGround-based and Airborne Instrumentation for Astronomy II - Marseille, France
Duration: Jun 23 2008Jun 28 2008

Publication series

NameProceedings of SPIE - The International Society for Optical Engineering
ISSN (Print)0277-786X


OtherGround-based and Airborne Instrumentation for Astronomy II

All Science Journal Classification (ASJC) codes

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Applied Mathematics
  • Electrical and Electronic Engineering
  • Computer Science Applications


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