Experimental Astronomy

, Volume 45, Issue 2, pp 219–229 | Cite as

Optical design of visible emission line coronagraph on Indian space solar mission Aditya-L1

  • N. Raj Kumar
  • B. Raghavendra Prasad
  • Jagdev Singh
  • Suresh Venkata
Original Article


The ground based observations of the coronal emission lines using a coronagraph are affected by the short duration of clear sky and varying sky transparency. These conditions do not permit to study small amplitude variations in the coronal emission reliably necessary to investigate the process or processes involved in heating the coronal plasma and dynamics of solar corona. The proposed Visible Emission Line Coronagraph (VELC) over comes these limitations and will provide continuous observation 24 h a day needed for detailed studies of solar corona and drivers for space weather predictions. VELC payload onboard India’s Aditya-L1 space mission is an internally occulted solar coronagraph for studying the temperature, velocity, density and heating of solar corona. To achieve the proposed science goals, an instrument which is capable of carrying out simultaneous imaging, spectroscopy and spectro-polarimetric observations of the solar corona close to the solar limb is required. VELC is designed with salient features of (a) Imaging solar corona at 500 nm with an angular resolution of 5 arcsec over a FOV of 1.05Ro to 3Ro (Ro:Solar radius) (b) Simultaneous multi-slit spectroscopy at 530.3 nm [Fe XIV],789.2 nm [Fe XI] and 1074.7 nm [Fe XIII] with spectral dispersion of 28mÅ, 31mÅ and 202mÅ per pixel respectively, over a FOV of 1.05Ro to 1.5Ro. (c) Multi-slit dual beam spectro-polarimetry at 1074.7 nm. All the components of instrument have been optimized in view of the scientific objectives and requirements of space payloads. In this paper we present the details of optical configuration and the expected performance of the payload.


Space instrumentation Coronagraph Spectrograph Optics Solar physics 



The authors gratefully acknowledge the Indian Space Research Organization for funding the project.


  1. 1.
    Singh, J., et al.: Detection of short-period coronal oscillations during the total solar eclipse of 24 October 1995. Sol. Phys. 170, 235–252 (1997)ADSCrossRefGoogle Scholar
  2. 2.
    Cowsik, R., Singh, J., Saxena, A.K., Srinivasan, R., Raveendran, A.V.: Short-period intensity oscillations in the solar corona observed during the total solar eclipse of 26 February 1998. Sol. Phys. 188, 89–98 (1999)ADSCrossRefGoogle Scholar
  3. 3.
    Singh, J., et al.: Intensity oscillation in the corona as observed during the total solar eclipse of 29 march 2006. Sol. Phys. 260, 125–134 (2009)ADSCrossRefGoogle Scholar
  4. 4.
    Krishna Prasad, S., Singh, J., Ichimoto, K.: Thermal structure of coronal loops as seen with norikura coronagraph. Astrophys J Lett. 765, L46 (5pp) (2013). ADSCrossRefGoogle Scholar
  5. 5.
    Gallagher, D., et al.: The COSMO coronagraph optical design and stray light analysis. Proc. SPIE. 9906, 990654–990651 (2016). CrossRefGoogle Scholar
  6. 6.
    Fineschi, S., et al.: METIS: a novel coronagraph design for the Solar Orbiter mission. Proc. SPIE. 8443, 84433H–844331 (2012). CrossRefGoogle Scholar
  7. 7.
    Brueckner, G.E., et al.: The large angle spectroscopic coronagraph (LASCO) visible light coronal imaging and spectroscopy. Sol. Phys. 162, 357–402 (1995)ADSCrossRefGoogle Scholar
  8. 8.
    ISRO: Aditya-L1 first Indian mission to study the sun., , (2016)
  9. 9.
    Singh, J., et al.: Proposed visible emission line coronagraph. Curr. Sci. 100(2), 167 (2011)Google Scholar
  10. 10.
    Singh, J., Bayanna, R., Sankarasubramanian, K.: Visible emission line space solar coronagraph: science and optical design. J. Opt. 42, 96 (2013). CrossRefGoogle Scholar
  11. 11.
    Raja Bayanna, A., Mathew, S.K., Sankarasubramanian, K., Venkatakrishnan, P., Singh, J., Prasad, B.R.: Issues with external occultation of a coronagraph. Exp. Astron. 29, 145–153 (2011). ADSCrossRefGoogle Scholar
  12. 12.
    Sankarasubramanian, K.: Solar coronal studies with Aditya-1 mission. 31st ASI Meet. ASI Conf. Ser. 9, 43–48 (2013)Google Scholar
  13. 13.
    Venkata, S.N., Raghavendra Prasad, B., Nalla, R.K., Singh, J.: Scatter studies for visible emission line coronagraph on board ADITYA-L1 mission. J Astron Telescopes Instrum Syst. 3(1), 014002 (2017). ADSCrossRefGoogle Scholar

Copyright information

© Springer Science+Business Media B.V., part of Springer Nature 2018

Authors and Affiliations

  • N. Raj Kumar
    • 1
    • 2
  • B. Raghavendra Prasad
    • 1
  • Jagdev Singh
    • 1
  • Suresh Venkata
    • 1
  1. 1.Indian Institute of AstrophysicsBangaloreIndia
  2. 2.ATG EuropeNoordwijkNetherlands

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