We consider the Solar Cycle - the variation in any solar, heliospheric or cosmic ray parameter, related to the well-known 22-year dynamo-like process on the Sun - and discuss how it is influenced by the inner (the transformation of the solar activity in the basement of the heliosphere) and the external (the interaction between the solar and interstellar winds) factors. The corresponding approaches to the description of the long-term variations (the Solar Cycle, secular and longer ones) in the galactic cosmic ray intensity are outlined.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

Signs of quasi-regular structures in time-averaged photospheric images are described.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

The Astronomical Unit is one of the most basic units of astronomy: the scale of the solar system. Yet its long and colorful history is sprinkled liberally with incorrect descriptions and mis-quoted definitions – today as much as ever. Over the last half century, the accuracy of the au determinations has improved dramatically: optical (triangulation) methods have given way to modern electronic observations, high-speed computers, and dedicated efforts to improve planetary ephemerides. Typical uncertainties in the value of the au have decreased from many tens of thousands of kilometers to the present level of only a few meters. With the solar system providing a very clean, undisturbed dynamical model, the ephemerides have been used for a variety of exotic physical tests: alternative theories of gravitation, $d({\rm G})/dt$, $d({\rm au})/dt$, etc. In the beginning of this modern era, the author happened to be a witness to a couple of rather key events; more lately, a participant. A couple of these personal experiences are related.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

Halo CMEs represent the three-dimensional moving structures, located out of the plane of the sky (Howard et al. 1982, St. Cyr et al. 2000). At that one halo CMEs move toward the Earth (frontside Halo CMEs), other - away from the Earth, St. Cyr. Frontside halo CMEs play the special role in phenomena, associated with space weather, Crosby (2001). The largest geomagnetic storms are caused by influencing such CMEs on the magnetosphere of the Earth (Webb et al. 2000, St. Cyr et al. 2000). Using the images of halo CMEs in the field of view of a coronagraph it is possible to determine only their apparent characteristics in the plane of the sky. But in this case it is difficult define its important parameters such as directions of movement, angular sizes in various sections of CME, position of the CME “center” or of its front, velocities of CME elements along directions which are not located in the plane of the sky. Without these parameters it is impossible to find the mass of CME, it's kinetic and potential energy. In the present work the methods are offered and approved allowing the estimation of the listed above halo CMEs parameters, which are determined with difficulty.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

Oscillations of the magnetic field in sunspot umbra have been detected by Pulkovo CCD spectroheliograph-magnetograph. The manifestations of 3- min oscillations in the power spectra of magnetic field variations are not very strong and can be seen only in a number of larger sunspots. Their power is concentrated in isolated small regions of the boundary between umbra and penumbre of large spots. The waves are produced in short bursts with coherence times of about 10 min. In the sunspot umbra, 30-40 min modes have been also confidently revealed.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

The change in the measured position due to the chromatic effect in the optical system is usually so small that it can be neglected. However, in the case of the Hipparcos mission, this effect is of the same magnitude as the targeted precision; it is therefore mandatory to correct for it. The different assumptions adopted to build up such corrections in the Hipparcos framework are presented. Some of their limitations and how they can be overcome to improve the results even today are described. The chromaticity mainly affects red stars and has its strongest impact on the astrometry of very red and highly variable stars such as Miras. Nevertheless, the implications on distance scale determination are rather small.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

We report on detection of coronal streamer trace on the night sky over the horizon.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

The Events of energetic particles from solar X-ray flares and shock waves have been studied. The data were taken from the National Geophysical data center (NGDC) in Boulder, Colorado, USA, Where the data were taken during the solar cycle 23rd. The 23rd cycle is the present one, that started in April 1996, and its maximum was in May 2001, and it will be decayed during year 2007. Power spectrum methods have been applied for analysis of the data given, to find the short and intermediate periodicities. The periodicity around 14 days has appeared in this analysis. This has important implications for understanding and predicting the effects of solar activity on the Earth and on the earth's atmosphere. If a Coronal Mass Ejections (CMEs) hit the Earth, it can excite a geomagnetic storm. Large geomagnetic storms, among other things, can cause electrical power which can damage satellite communications. In space CME typically drive shock waves that produce energetic particles that can damage both electronic equipment and astronauts that are outside the protection of the Earth's magnetic field. So, the prediction of the high energetic particle events is of vital importance for space navigation and airline disasters.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

During the second half of the nineteenth century Brazilian astronomers participated in the observations of transit of Venus. In 1874 a Brazilian astronomer, Francisco Antônio de Almeida was sent by the Imperial Observatory to Nagasaki to use the “photographic revolver” invented by Jules Janssen. In 1882 three missions were sent by the Imperial Observatory (Brazil) to observe the transit in St Thomas (Antilles), Punta Arenas (Chile) and Olinda (Brazil). The value of the solar parallax obtained by the Brazilian Commission, led by Luís Cruls, was 8.$\rlap ^{\prime\prime}$808, representing at that time one of the most precise values.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

The cause of 92 geomagnetic disturbances in the period of 1997 – 2003 was analyzed. There were used data from LASCO C3 instrument from SOHO satellite, SOHO LASCO CME Catatalog, and the daily average indices Ap. In this contribution we proposed to search sources of the geomagnetic storms taking into account the old idea by Newkirk and Bohlin (1965). According to this idea a solar coronal streamer can cause geomagnetic disturbance when it crosses the Earth's space.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

Coronal mass ejections (CMEs) are accompanied by several other active phenomena. However, neither their interrelation, nor CMEs' trigger mechanisms have not yet been adequately understood.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

A white-light flare on 2001 March 10 was well observed in the H$\alpha$ line and Ca II $\lambda$8542 line using the imaging spectrograph installed in the Solar Tower Telescope of Nanjing University. Three small sunspots appeared in the infrared continuum image, one of which showed that the infrared continuum is enhanced by 4%-6% compared to the preflare value and it almost disappeared in the continuum image for about 3 min. Near the sunspot, there appeared a hard X-ray (HXR) source, the flux of which showed a good time correlation with the profile of the continuum emission. We propose that electron precipitation followed by radiative backwarming may play the chief role in heating the sunspot.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

Three approaches for coronal magnetic loops on the Sun and the stars are considered: (i) loop as MHD-resonator, (ii) loop as electric circuit, (iii) loop as a magnetic mirror trap.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

We investigated variations of the radio emission of the whole Sun at 1.76 cm obtained and archived at the Nobeyama radio heliograph in 1992–2003. For this purpose the daily data of the intensity and also right/left circular polarization of the radio emission with one-second average were processed. It was found that 3 minutes oscillations are present at the different phases of solar activity, including the minimum of activity. Especially conspicuous these oscillations present in a difference between the right and the left circular polarization. Intensity of the oscillations changes with a level of the solar activity. As we register fluctuations from the full Sun that their source can be not only sunspots but also and chromosphere of the Sun. Spectral analysis of the presence of 3-minute oscillations in polarization of the solar radio emission shows that there exist modulation with the periods of 27 and 157 days.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

The phenomena ($\sim 15$ cases) observed with Siberian Solar Radio Telescope (SSRT) in 2003–2004 years are under investigations. These phenomena are identified with CMEs by LASCO and with the associated active regions (ARs). The structure of low corona above these ARs is studied using the observations with RATAN–600. The aim of this cooperative investigation is to follow this phenomenon at the earliest stage when it is developing in low corona.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

This paper reviews some recent results obtained from multi-wavelength studies that extend from white light to radio. Special emphasis is given to radio observations, which can be used to determine emission mechanisms and to trace electron propagation paths and plasma motions. Multi-wavelength comparisons have been found to be essential when analysing flare- and CME-related eruptions, but significant results have also been obtained in ‘quiet’ Sun studies.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

In our contribution we introduce the new Interferometric BIdimensional Spectrometer (IBIS) and present the first results on bisector velocities of two dimensional spectral scans in FeI 7090.4 Å comparing granules and intergranular regions.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

The description of two major flares detected by SONG spectrometer on board the CORONAS-F mission during famous period of solar activity in October- November 2003 and their comparison with soft X-ray measured by GOES-12 is given.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

We investigate the line-of-sight velocity oscillations in the sunspot NOAA 0051 during it's disk transit. A favorable concourse of circumstances (observational method, excellent seeing plus intrinsic processes in the sunspot) allowed us to observe in some instances a clear picture of waves propagating in the umbra chromosphere (chevron structure in figure 1). Thus it was possible to measure directly their phase velocity in the immediate region of sunspot umbra. These waves have a period of 2.8 min and propagate from the sunspot center outward with the phase velocity of 45–60 km s$^{-1}$ with the line-of-sight velocity amplitude of about 2 km s$^{-1}$ (figure 2, 3). The waves terminate rather abruptly on the umbra boundary and show no direct linkage with (RPW) running penumbral waves (Zirin and Stein 1972). We pointed out that in our observations the picture of propagation of the waves from the sunspot center in two opposite directions is not accompanied by the propagation of H$\alpha$ umbral flashes in these same directions. Our investigations showed that three-minute oscillations are very poorly pronounced in H$\alpha$ intensity, and no “chevron” structure is present. The spatial coherence of the waves at the umbra center is no more than 2$^{\prime\prime}$. No phase delay was found between line-of-sight velocity signals measured in H$\alpha \pm$0.2 Å and H$\alpha \pm$0.7 Å for a single spatial element. This would imply that the vertical extent of the source is comparable to the observed height scale (1000–1500 km). At the photospheric level there are clearly pronounced periodic motions (T $\sim$5 min) propagating from the umbra and from the superpenumbra to the lines of maximum Evershed velocity. One gets the impression that in some portions the Evershed flow itself is pulsating (Kobanov 2000; Rimmele 1995). Balthasar and Wiehr (1990) developed the idea that the Evershed flows may be a result of superposition of some penumbral structure affected by the underlying oscillating layers. Numerical simulations of wave propagation in a stratified magneto-atmosphere presented by Bogdan et al. (2003) show that the coupling between the fast and slow magneto-acoustic-gravity waves is confined to thin atmospheric layers where the sound speed and the Alfen velocity are comparable in magnitude. Their coherent superposition presents a large variety of Doppler and intensity time series. Interesting, some of their pictures resemble our “chevrons”.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

We computed chromospheric models of the Sun as a star and of nine solar analogues. The stars have a wide variety of magnetic activity levels, which allows us to study the differences in atmospheric structures induced by activity.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html