2004 ASTRONOMY & ASTROPHYSICS - Indian Academy of Sciences

SOLAR PHYSICS
Some Possible
New Initiatives
A Coronograph in space
The highly successful Indian X-ray Astronomy
Experiment on IRS P3, and the recently launched
Solar X-ray Spectrometer ( SOXS ) on GSAT 2,
have demonstrated the efficacy of launching small
piggy back payloads.
The next such satellite borne instrument could be
a small size coronograph (10 cm aperture) with
very fast (f/1 to f/2) optics that produces a very
small image of the sun. The heating problem can
be avoided by reflecting away the central disc
portion which is not required in a coronogram.
The science goal would be to track CMEs (Coronal
Mass Ejections) up to 50 solar radii. Since travel
time over one solar radius is almost 45 minutes,
there is sufficient time for raster scanning of the
corona. Hence single pixel detectors can be used,
thereby having very small power and weight
requirements. This is therefore an ideal candidate
for a piggy back payload. The tracking
requirement can be reduced since one would
need sampling only at radial intervals of half a
degree, and the occulting disc can be made as
large as 5 solar radii.
A Solar Telescope
Given the great excitement in solar physics, a
major new facility in India will help to attract
bright young people to this area. A 50 cm class
Solar Telescope could be the next initiative.
Such a telescope should be a modern facility for
solar research and should cater to the
contemporary needs of the nation’s solar
astronomy and solar-terrestrial physics communities.
A key question to be asked is whether there is a
site good enough to justify such a telescope. It is
now well established that solar telescopes located
The Solar Corona in white light
The intensity and polarization map of the solar
corona taken during the eclipse of 2001.
Courtesy: Udaipur Solar Observatory
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