Sunrise-III: A balloon-borne observatory
In July 2024, Sunrise completed its third successful science flight. The Sunrise-III observatory had been upgraded significantly after the two previous successful flights in 2009 and 2013, to tackle the most recent science challenges concerning the solar atmosphere. Three completely new instruments focus on the small-scale physical processes and their complex interaction from the deepest observable layers in the photosphere up to chromospheric heights. Previously poorly explored spectral regions and lines are exploited to paint a three-dimensional picture of the solar atmosphere with unprecedented completeness and level of detail.
The full polarimetric information is captured by all three instruments to reveal the interaction
between the magnetic fields and the hydrodynamic processes. Two slit-based spectropolarimeters,
the Sunrise UV Spectropolarimeter and Imager (SUSI) and the Sunrise Chromospheric
Infrared
spectro-Polarimeter (SCIP), focus on the near-ultraviolet (309 - 417 nm) and the
near-infrared
(765 – 855 nm) regions respectively, and the imaging spectropolarimeter Tunable Magnetograph
(TuMag)
simultaneously obtains maps of the full field-of-view of 46×46 Mm2 in the photosphere
and the chromosphere in the visible (525 and 517 nm).
The instruments are operated in an
orchestrated mode, benefiting from a new Image Stabilization and Light Distribution unit (ISLiD),
with the Correlating Wavefront Sensor (CWS) providing the autofocus control and an image
stability with a root-mean-square value smaller than 0.005".
A new gondola was constructed to significantly improve the telescope pointing stability,
required to achieve uninterrupted observations over many hours.
Sunrise-III was launched successfully on 10 July 2024, from the Esrange Space Center of the Swedish Space Corporation near Kiruna (Sweden). It reached the landing site between the Mackenzie River and the Great Bear Lake in Canada after a flight duration of 6.5 days. In this paper, we give an overview of the Sunrise-III observatory and its instruments.
Co-Observations
During the roughly 6.5 day-long flight, Sunrise pointed at the Sun for 152.2 h, having lock
on a solar target for 102.7 h, the remaining time was mainly used for calibration measurements
(finding solar limbs to accurately determine the position on the solar disc, dark current measurements,
flat-fields, phase diversity measurements in the case of TuMag), or to select and lock on the correct
solar target (and wavelength region in the case of SUSI).
Some observing time was lost because of seeing when the Sun was partly behind the Earth’s atmosphere
(although a large fraction of this time was used for calibration purposes), and a few hours were spent
recovering588from errors.
Careful planning allowed most of the originally planned observations to be carried out,
with the 240 TB hardisks being 80% full by the end of the mission. The list of targets includes
the quiet Sun, sunspots, emerging flux regions, plage, flares, spicules at the poles,
the East and West limbs, a coronal hole, and filaments. Nearly 31% of the
science observations were
dedicated to the quiet Sun, followed by sunspots (22%) and plage (12%) while other targets were
observed less often. Although Sunrise-III concentrated on regions
close to
disc centre, it did also observe regions close to and at the limb as well as at intermediate μ=cosθ,
where θ is the heliocentric angle.
There was also an impressive number of coordinated co-observations with Sunrise-III done by almost all medium- and high-resolution ground-based solar tele-scopes and by all high-resolution solar space missions. See Korpi-Lagg et al. (2025) for a detailed list of participating observatories.
from Solanki et al. (2026)
These coordinated observations are either co-spatial and co-temporal, enlarging the available
spatial and spectral information, or preview and follow-up observations of targets
Sunrise-III has already left behind and thereby enlarging
the temporal coverage.
For access of the co-observation datasets, please reach out to the corresponding institutes and
observatories
Institutes and partners
Flight path
Animation courtesy: David Orozco Suárez
Sunrise-III instruments
The
Sunrise-III UV Spectropolarimeter and Imager (SUSI)
The
Tunable Magnetograph (TuMag)
The
Sunrise Chromospheric Infrared Spectro-Polarimeter
(SCIP)Sunrise-III Team
Sunrise-III links
Göttingen Operations Center (GOC) 2024
