Solar Physics

, Volume 210, Issue 1, pp 61–86

The RHESSI Imaging Concept

  • G.J. Hurford
  • E.J. Schmahl
  • R.A. Schwartz
  • A.J. Conway
  • M.J. Aschwanden
  • A. Csillaghy
  • B.R. Dennis
  • C. Johns-Krull
  • S. Krucker
  • R.P. Lin
  • J. McTiernan
  • T.R. Metcalf
  • J. Sato
  • D.M. Smith
Article

DOI: 10.1023/A:1022436213688

Cite this article as:
Hurford, G., Schmahl, E., Schwartz, R. et al. Sol Phys (2002) 210: 61. doi:10.1023/A:1022436213688

Abstract

The Reuven Ramaty High-Energy Solar Spectroscopic Imager (RHESSI) observes solar hard X-rays and gamma-rays from 3 keV to 17 MeV with spatial resolution as high as 2.3 arc sec. Instead of focusing optics, imaging is based on nine rotating modulation collimators that time-modulate the incident flux as the spacecraft rotates. Starting from the arrival time of individual photons, ground-based software then uses the modulated signals to reconstruct images of the source. The purpose of this paper is to convey both an intuitive feel and the mathematical basis for this imaging process. Following a review of the relevant hardware, the imaging principles and the basic back-projection method are described, along with their relation to Fourier transforms. Several specific algorithms (Clean, MEM, Pixons and Forward-Fitting) applicable to RHESSI imaging are briefly described. The characteristic strengths and weaknesses of this type of imaging are summarized.

Copyright information

© Kluwer Academic Publishers 2002

Authors and Affiliations

  • G.J. Hurford
    • 1
  • E.J. Schmahl
    • 2
    • 3
  • R.A. Schwartz
    • 3
  • A.J. Conway
    • 4
  • M.J. Aschwanden
    • 5
  • A. Csillaghy
    • 1
    • 6
  • B.R. Dennis
    • 3
  • C. Johns-Krull
    • 7
  • S. Krucker
    • 1
  • R.P. Lin
    • 1
    • 8
  • J. McTiernan
    • 1
  • T.R. Metcalf
    • 5
  • J. Sato
    • 9
  • D.M. Smith
    • 1
  1. 1.Space Sciences LaboratoryUniversity of CaliforniaBerkeleyU.S.A
  2. 2.Astronomy DepartmentUniversity of MarylandCollege ParkU.S.A
  3. 3.Lab for Astronomy and Solar PhysicsNASA Goddard Space Flight CenterUSA
  4. 4.Department of Physics and AstronomyThe Open UniversityMilton KeynesU.K
  5. 5.Solar & Astrophysics Laboratory, Dept. L9-41Lockheed Martin Advanced Technology CenterPalo AltoU.S.A
  6. 6.University of Applied SciencesWindischSwitzerland
  7. 7.Department of Physics and AstronomyRice UniversityHoustonU.S.A
  8. 8.Department of PhysicsUniversity of California, BerkeleyCAU.S.A
  9. 9.Department of PhysicsMontana State UniversityBozemanU.S.A