Kanzelhöhe Observatory (KSO) regularly performs high-cadence fulldisk imaging of the solar chromosphere in the Hα and Ca ii K spectral lines as well as the solar photosphere in white-light. In the frame of ESA's Space Situational Awareness (SSA) programme, a new system for real-time Hα data provision and automatic flare detection was developed at KSO. The data and events detected are published in near real-time at ESA's SSA Space Weather portal (http://swe.ssa.esa.int/web/guest/kso-federated). In this paper, we describe the Hα instrument, the image recognition algorithms developed, the implementation into the KSO Hα observing system and present the evaluation results of the real-time data provision and flare detection for a period of five months. The Hα data provision worked in 99.96% of the images, with a mean time lag between image recording and online provision of 4 s. Within the given criteria for the automatic image recognition system (at least three Hα images are needed for a positive detection), all flares with an area ≥50 micro-hemispheres and located within 60• of the Sun's center that occurred during the KSO observing times were detected, in total a number of 87 events. The automatically determined flare importance and brightness classes were correct in ∼85%. The mean flare positions in heliographic longitude and latitude were correct within ∼1• . The median of the absolute differences for the flare start times and peak times from the automatic detections in comparison to the official NOAA (and KSO) visual flare reports were 3 min (1 min).
We study spectroscopic observations of chromospheric evaporation mass flows in comparison to the energy input by electron beams derived from hard X-ray data for the white-light M2.5 flare of 2006 July 6. The event was captured in high cadence spectroscopic observing mode by SOHO/CDS combined with highcadence imaging at various wavelengths in the visible, EUV and X-ray domain during the joint observing campaign JOP171. During the flare peak, we observe downflows in the He i and O v lines formed in the chromosphere and transition region, respectively, and simultaneous upflows in the hot coronal Si xii line. The energy deposition rate by electron beams derived from RHESSI hard X-ray observations is suggestive of explosive chromospheric evaporation, consistent with the observed plasma motions. However, for a later distinct X-ray burst, where the site of the strongest energy deposition is exactly located on the CDS slit, the situation is intriguing. The O v transition region line spectra show the evolution of double components, indicative of the superposition of a stationary plasma volume and upflowing plasma elements with high velocities (up to 280 km s −1 ) in single CDS pixels on the flare ribbon. However, the energy input by electrons during this period is too small to drive explosive chromospheric evaporation.These unexpected findings indicate that the flaring transition region is much more dynamic, complex, and fine-structured than is captured in single-loop hydrodynamic simulations.
Kanzelhöhe Observatory (KSO) was founded during World War II by the "Deutsche Luftwaffe" (The German Airforce) as one station of a network of observatories, which would provide information on solar activity in order to better assess the actual conditions of the Earth's ionosphere in terms of radiowave propagation. Solar observations began in 1943 with photographs of the photosphere and drawings of sunspots, plage regions and faculae, as well as patrol observations of the solar corona. At the beginning all data were sent to Freiburg (Germany). After WW II international cooperation was established and the data were sent to Zurich, Paris, Moscow, and Greenwich. Relative sunspot numbers are derived since 1944. The agreement between relative sunspot numbers derived at KSO and the new International Sunspot Number (ISN) (SILSO World Data
Kanzelhöhe Observatory for Solar and Environmental Research (KSO) of the University of Graz (Austria) is in continuous operation since its foundation in 1943. Since the beginning, its main task was the regular observation of the Sun in full disc. In this long time span covering almost seven solar cycles, a substantial amount of data was collected, which is made available online. In this article we describe the separate processing steps from data acquisition to high level products for different observing wavelengths. First of all we present in detail the quality classification, which is important for further processing of the raw images. We show how we construct centre-to-limb variation (CLV) profiles and how we remove large scale intensity variations produced by the telescope optics in order to get images with uniform intensity and contrast. Another important point is an overview of the different data products from raw images to high contrast images with heliographic grids overlaid. As the data products are accessible via different sources, we also present how to get information about the availability and how to obtain these data. Finally, in an appendix, we describe in detail the information in the FITS headers, the file naming and the data hierarchy.
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