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Context. The populations of small bodies of the Solar System (asteroids, comets, Kuiper-Belt objects) are used to constrain the origin and evolution of the Solar System. Both their orbital distribution and composition distribution are…
Sunspots have been known in the West since Galileo Galilei and Thomas Harriot first used telescopes to observe the Sun nearly four centuries ago; they have been known to the Chinese for more than two thousand years. They appear as…
Catalogs of the Zurich Observatory contain positional information on sunspots, prominences and faculae in late 19th and early 20th centuries. This database is given in handwritten tabular form and was not systematically analysed earlier. It…
Kp-Index is a very important factor for determining how the Sun's magnetic field is affecting the Earth's magnetic field and help us prepare for the worst (like solar or geomagnetic storms). Currently there are around thirteen observation…
More than 70 years ago it was recognised that ionospheric F2-layer critical frequencies $foF2$ had a strong relationship to sunspot number. Using historic datasets from the Slough and Washington ionosondes, we evaluate the best statistical…
There exists a considerable amount of research claiming a puzzling anti-correlation between the neutrino detection rate at the Homestake experiment and indicators of solar activity such as the sunspot number, giving rise to explanations…
Dark (hidden) photons are widely recognised as well motivated candidates for physics beyond the standard model, and have been invoked for the solution of several outstanding problems, including to account for the dark matter in the…
Kodaikanal Solar Observatory (KoSO) is one of the oldest solar observatories, possessing an archive of multi-wavelength solar observations, including white light, Ca II K, and H-alpha images spanning over a century. In addition to these…
We analysed the combined Greenwich (1874-1976) and Solar Optical Observatories Network (1977-2011) data on sunspot groups. The daily rate of change of the area of a spot group is computed using the differences between the epochs of the spot…
The $F_{10.7cm}$ radio flux and the Sunspot Number are the most widely used long-term indices of solar activity. They are strongly correlated, which led to the publication of many proxy relations allowing to convert one index onto the…
NASA's Interface Region Imaging Spectrograph (IRIS) provides high resolution observations of the solar atmosphere through UV spectroscopy and imaging. Since the launch of IRIS in June 2013, we have conducted systematic observation campaigns…
Relative variations in the number of sunspots and sunspot groups in activity cycles have been analyzed based on data from the Kislovodsk Mountain Astronomical Station and international indices. The following regularities have been…
The global neutron monitor network has been successfully used over several decades to study cosmic ray variations and fluxes of energetic solar particles. Nowadays, it is used also for space weather purposes, e.g. alerts and assessment of…
Ahead-of-time forecasting of incident solar-irradiance on a panel is indicative of expected energy yield and is essential for efficient grid distribution and planning. Traditionally, these forecasts are based on meteorological physics…
Sky-image-based solar forecasting using deep learning has been recognized as a promising approach in reducing the uncertainty in solar power generation. However, one of the biggest challenges is the lack of massive and diversified sky image…
Gil-Alana et al. (Physica A: 396, 42-50, 2014) compared the sunspot number record and the temperature record and found that they differ: the sunspot number record is characterized by a dominant 11-year cycle while the temperature record…
We report the simultaneous presence of chromospheric umbral flashes and associated umbral waves, and propagating coronal disturbances, in a sunspot and related active region. We have analyzed time-distance maps obtained using the…
Records of observations of sunspots and auroras in pre-telescopic historical documents provide useful information about past solar activity both in long-term trends and short-term space weather events. In this study, we present the results…
A specific type of artifacts, that originate due to displacement of the image of a moving object along the digital (pixel) matrix of receiver are analyzed in detail. The criteria of appearance and the influence of these artifacts on the…
We present a detailed comparison between simulations and seeing-free observations that takes into account the crucial influence of instrumental image degradation. We use images of quiet Sun granulation taken in the blue, green and red…