SUNRISE
A balloon-borne solar telescope
The SUNRISE project aims at high-resolution spectro-polarimetric
observations of the solar atmosphere on the intrinsic spatial scale of
its magnetic structure. The SUNRISE telescope with 1 m aperture and its
instruments will provide spectra and images resolving spatial scales
down to 35 km on the Sun. The main scientific goal of the mission is to
understand the formation of magnetic structures in the solar atmosphere
and to study their interaction with the convective plasma flows.
Science objectives
Solar magnetism provides one of the great challenges of
astrophysics. Its intricate field structure exemplifies cosmic magnetic
fields. Its modulation affects the human environment. The universe
abounds with objects that are dominated by magnetohydrodynamical and
plasma processes, but of all astronomical objects only the Sun offers
the possibility to directly and quantitatively investigate these
processes with sufficient resolution.
The central aim of the SUNRISE project is to understand the structure
and dynamics of the magnetic field in the solar atmosphere. The magnetic
field is the source of solar activity, controls the space environment of
the Earth and causes the variability of solar irradiance, which may be a
significant driver of long-term changes of the terrestrial
climate. Interacting with the convective flow field, the magnetic field
in the solar photosphere develops intense field concentrations on scales
below 100 km, which are crucial for the dynamics and energetics of the
whole solar atmosphere. These spatial scales cannot be studied
systematically from the ground because of image distortion by turbulence
in the lower atmosphere of the Earth. The balloon-borne SUNRISE
telescope will, for the first time, provide measurements of the magnetic
structure of the solar atmosphere on its intrinsic spatial and temporal
scales.
The SUNRISE instrumentation consists of a light-weight solar
telescope of 1 m aperture, a spectrograph-polarimeter (SUPOS) for
high-precision spectral line measurements in the linearly and circularly
polarized light, a filtergraph (SUFI) for high-resolution images in the
visible and UV spectral ranges, and a magnetograph (IMaX) providing
two-dimensional maps of the complete magnetic field vector and the
line-of-sight velocity. The telescope is kept aligned and focussed by an
innovative control system based upon a wavefront sensor. Image
stabilisation is achieved with a correlation tracker controlling a
high-speed steering mirror.
Beginning in 2009, the telescope will be operated during a series
of stratospheric balloon flights in order to obtain diffraction-limited
image quality and to study the UV spectral region down to 220 nm, which
is not accessible from the ground. The facilities of the National
Scientific Balloon Facility of NASA and, when available, Ultra Long
Duration Balloons will be used. The experience gained by successful
balloon flights will put SUNRISE in a good position to become the
central element of a future space borne solar observatory.
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MPS contribution
MPS is the PI institution and coordinates the SUNRISE project (PI:
S.K. Solanki, Project Manager: P. Barthol, Project Engineer: R. Meller,
Project Scientist: A. Gandorfer). The SUNRISE main telescope will be
built through an industry contract by Kayser-Threde under supervision of
MPS. Main parts of the postfocus instrumentation (PFI) will be built at
MPS, i.e. the PFI structure, the light distribution and image
stabilisation unit (ISLiD), the filtergraph (SUFI), and the
spectro-polarimeter (SUPOS). Further hardware contributions of MPS are
the instrument control unit (central computer, ICU) and the data storage
system.
Related links
SUNRISE is a joint project of
