Report of SCOSTEP

Ground-Based Observations

The ground-based observations of the Sun are continuously realized at the Skalnaté Pleso Solar Observatory (20.24° E, 49.19° N) being managed within the frame of AISAS.
     The observational facilities are systematically modernized. The equipment exploited allows the observation of sunspots (since 1943), prominences (since 1964), emissions at highly ionized lines of solar corona (since 1965), and solar flares (since 1971, however with intervals of occasional observations).
     To study solar corona a coronal station at Lomnický Štít (20.22° E, 49.20° N, 2 634 m) was founded in 1962, where now the double 20 cm lens coronographs are installed. Observations of coronal emission lines are carried out regularly using a photoelectric photometer.
     New devices were recently established at Stará Lesná Observatory: a 15 cm lens chromospheric telescope equipped with H-alpha filter and a 20 cm lens photospheric telescope. A new horizontal spectrograph has following parameters: a 50 cm coelostat mirror, a 40 cm lens with f = 40 m and spectral resolution of 0.2 mm/0.1 nm.
     The optical fibre technique is recently used for spectrographic observations at Stará Lesná Observatory.
     The observations of sunspots, solar flares, prominences, solar emission corona are performed on a regular basis.

In the IEPSAS, the Department of Space Physics community has long-term experience with measurements of corpuscular radiation in the Earth's environment. Ground-based observations are carried out under the unique high altitude conditions of High Tatras mountains. At the observatory Lomnický Štít (Lomnicky Peak) the IGY neutron monitor was initially used. That was later reconstructed as NM64. This device has been providing continuous data on primary cosmic rays since December 1, 1981 (vertical cutoff rigidities 4GV, average count rate 1.6 x 10⁶ hr^-1). The data are at disposal of World Data Centers.

The Lomnický Štít station was among those three stations (together with Jungfraujoch, Swiss and Rome, Italy) which detected the first GLE of solar neutrons on June 3, 1982. This fact motivated the efforts for a better temporal resolution, which is 10 sec now. The joint experiment (in cooperation with Turku University, Finland) has been running since 1989. High statistical accuracy of NM data allowed to investigate variability of power spectra of NM time series (Kudela et al. 1995, Kudela et al. 1996a, b).

Geomagnetic observation are carried out on a continuous basis at the Hurbanovo Geomagnetic Observatory (j =47.87° N, l =18.18° E; F =46.89° N, L =101.12° E) of the GISAS. The recent modernization of the equipment includes the installation of digital variometers from Poland (1996) and magnetoregistration device DI Fluxgate (1997) gained on the basis of co-operation with GeoForschungsZentrum Potsdam and VW Stiftung (Germany).
     To keep international standards comparative measurements are realized on a regular basis since 1953 in cooperation with European observatories (e.g. Niemegk, Tihany, Moscow, Wien-Kobenzl). The long time series data make it possible to study the profiles of secular changes in the total field and its components (Váczyová 1997d).
     The observational results are pubIished (e. g. Váczyová 1997a, b, c) in annual reports (database since 1949) and submitted (recently also on diskettes) to WDC-A in Boulder, USA.
     The Hurbanovo Geomagnetic Observatory has gained the status of the IMO observatory and contributes to the realization of the INTERMAGNET programme.

Micropulsation measurements within the frame of the international network supported study have been started. The investigation of the non-linear character of the evolution of geomagnetic pulsations and their interaction with the background plasma at different levels of magnetospheric activity is under way in co-operation with US Geological Survey. Earlier observations of Pc3 pulsations were used to analyse their statistical regularities (Stoeštík & Prigancová 1996).

The IXth IAGA WORKSHOP ON GEOMAGNETIC OBSERVATORY INSTRUMENTS, DATA ACQUISITION AND PROCESSING will be held at Hurbanovo on June 12-18, 2000. The workshop has longstanding traditions in testing geomagnetic instrumentation and at this time it will be dedicated to the 100th anniversary of the Hurbanovo Geomagnetic Observatory.

The importance of observational activities realized by the DGCU is growing. The Complex Astronomical and Geophysical Observatory has been built at Modra-Piesok near Bratislava. At this observatory the measurements of the geomagnetic field elements are carried out with high time resolution (1-min data) since 1992. The modernization of data processing is under way.
According to the new project the measurements of Schumann resonances at the Modra - Piesok Observatory are carried out. The measurements without utilization of cryogenic apparatus have been also preparing.