We observed a sunspot almost exactly at disc centre on 23 September, 2003, with the Tenerife Infrared Polarimeter (TIP; Martínez Pillet et al. 1999) at the $\phi=70$, cm Vacuum Tower Telescope (VTT) on Tenerife. The highly symmetric spot passed the central meridian just at the time of observations; its solar latitude of $9^\circ$ N was almost perfectly compensated by the inclination of the solar axis $B_0=7^\circ$. We took the full Stokes vector through the line profiles of Fe I 10783 Å, Si I 10784.5 Å and Si I 10786.8 Å. The spatial sampling was adapted to the pixel size of 0.4 arcsec width; the VTT correlation tracker largely compensated image motion. The Stokes spectra were corrected for the dark and the gain matrices, as well as for instrumental polarisation and Stokes cross-talk. The spectral resolution finally achieved with TIP and its detector amounts to 32 mÅ.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

Relations between the geomagnetic A$_p$-index and magnetic and flare parameters of the super active regions (SARs) are analysed. The small and mean SARs having the spot areas S$\le 1000\, \mu h$ seem to differ from the SARs being large $\delta$-spots (SARs-$\delta$) not only by their parameters but also by relations between them.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

We summarize the results of our studies of CME-associated EUV dimmings and coronal waves by ‘derotated’ fixed-difference SOHO/EIT heliograms at 195Å with 12-min intervals and at 171, 195, 284, 304Å with intervals of 6 or 12 hours.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

The CORONAS-F satellite has been launched on 31 July 2001 (Oraevsky et al. 2002). To conduct measurements of the intensity of solar radiation in the EUV spectral region near the hydrogen line $L_{\alpha}(\lambda = 121.6$ nm) the spectrophotometer VUSS was installed onboard CORONAS-F. A vacuum photodiode was used as EUV detector in VUSS with the $CuJ$ cathode and $MgF_2$ entrance window.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

In this paper we compare the intermittence properties of magnetic fluctuations (non-Gaussian shape of probability density functions) observed in the solar wind (ACE) with the simultaneous occurrence of intermittence in the Earth's plasma sheet (GEOTAIL). Intervals with different level of magnetic turbulence are investigated separately.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

The preflare plage spectra were obtained with the ATsU-26 solar telescope mounted at the Peak Terskol. The spectra were acquired from 1 h to 20 min before the flare onset. The most prominent peculiarity of all the observed events are the tilted $H_{\alpha}$-emission details which appear less than 40 min before the flare. This result may testify to spiral structure of the ascending $H_{\alpha}$ loops. The ascending velocities in the chromosphere attain more than 10 km/s. Two crossing $H_{\alpha}$ loops were observed to interact before 1n flare. As a result of their interaction, the redistribution of velocities occurs in the both chromosphere and photosphere. This can be a consequence of the preflare reconnection at the lower atmospheric layers. As the flare onset approaches the ascend of photospheric material start to dominate. The preflare line-of-sight velocities exceed considerably those in the neighbouring unperturbed regions.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

This paper sets Jeremiah Horrocks and Much Hoole in the context of Lancashire society on the eve of the English Civil War. It focuses on the complexities of what it was to be a “Puritan” in an environment where religious labels and conflicts mattered a great deal; it examines the economic circumstances of county and locality at the time, pointing out the extent to which (despite widespread and deep poverty) the county's merchants were looking outwards to London, northern Europe and beyond; and it emphasizes that even in the apparently remote and rustic location of Much Hoole it was possible for Horrocks to sustain a scientific correspondence and to keep in touch with, and make his contribution to, developments on a much wider stage.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

Solar energetic particles generated in solar proton events produce in SOHO/EIT (and LASCO) images well-known ‘snowstorm’ effect which interferes analyses of those images. Similar ‘snowstorms’ are also observed in TRACE and CORONAS-F/SPIRIT images due to particles continuously present in the radiation belts and polar caps.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

It was found that filaments observed in EUV could be much more extended than in H$\alpha$. These extended dark structures visible in EUV are named EUV filaments. Their parts seen only in EUV (not observable in H$\alpha$ because of low opacity at the H$\alpha$ wavelength) are called EUV-filament extensions (or simply EUV extensions). For the EUV filament observed by SoHO on 15 October 1999 as northern polar crown filament, only a few small dark structures were seen in H$\alpha$. This suggests that the mass of the EUV extension is larger than, or at least comparable with, the mass of the parts of the filament observed in H$\alpha$. In our previous work we determined the 3D structure of the EUV extension of this EUV filament. In this paper we present the determinations of mass and average density of this EUV extension. For better density estimates we interpret the hydrogen Lyman lines observed by SUMER using non-LTE radiative transfer code. From the best fitting of Lyman lines we obtained a reasonable model of the EUV extension with low gas pressure, temperatures from 2$\times10^4$ K to $10^5$ K and with extended prominence-corona transition regions.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

Moreton waves are flare-associated waves observed to propagate across the solar disk in H$\alpha$, especially in the wing of H$\alpha$. The Flare Monitoring Telescope at Hida Observatory of Kyoto University observed 12 events associated with flare waves (i.e., Moreton waves and/or filament oscillations) in H$\alpha$ from 1997 to 2002. We review our studies of Moreton waves based on these observations;

1. relation between EIT wave and Moreton wave (Eto et al. 2002),

2. simultaneous observation with X-ray wave (Narukage et al. 2002),

3. three dimensional structure of flare-associated wave (Narukage et al. 2004),

4. relation between Moreton waves and filament eruptions.

Specific features of magnetic reconnection in solar flares are briefly reviewed and illustrated. In particular, the large-scale structure and dynamics of large flares are interpreted in terms of the rainbow reconnection model. The role of the betatron effect in collapsing magnetic traps is considered.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

Here we analyse the solar cycle (SC) 23 behavior and we also make a comparison with some previous cycles and present a few aspects concerning the forecasts made for SC 23 maximum. As regards the following cycle, in accordance to other early predictions, our empirical method, based on observing the flare energy release during the descendant phase of the precedent SC, estimate that the amplitude of SC 24 will be low.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

In the present study a time series analysis of three of the most well-known Sun activity data series is made: 1) the Hoyt-Schatten (Group Sunspot Number $\mbox{\textit{Rg}}$)(Hoyt & Schatten 1988); 2) the Schove and 3) the Greenland (Dye-3 ice probe) ‘cosmogenic’ $^{10}Be$ concentration series (Schove 1983, Beer et al. 1998). The series “1” is based on instrumental observations for the last $\sim$400 years. The series “2” is a reconstruction of all Schwabe-Wolf cycle magnitudes after AD 296 by use of historical reports mainly for auroras and naked-eye visible sunspots. The series “3” is an indicator for the processes in outer solar corona and interplanetary space for the epoch AD 1423–1985. Two independent methods for time series analysis are used: 1) the $T$-$R$ periodogramm analysis (Komitov, 1986); 2) the method of Kaftan (2002).To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

Soft X-ray observations by Yohkoh SXT have revealed that transient brightenings of small coronal loops frequently occur in active regions. Their estimated energy is $10^{24} \sim 10^{28}$ ergs and non-thermal behaviors may be observed in the large member of the brightenings. They are considered as soft X-ray signatures of microflares observed in hard X-rays. Lower coronal temperature plasma (1-2MK) produced by Yohkoh transient brightenings is simultaneously observed in EUV wavelengths by TRACE and SoHO EIT/CDS. Moreover, EUV observations have shown a lot of tinier transient brightenings without accompanying SXT transient brightenings. Coordinated observations with photospheric observations show that the location of Yohkoh transient brightenings is well localized in active regions, i.e., in emerging flux regions, around well-developed sunspots, and in the coronal bundles connecting the leading plage to the following plage regions. In some Yohkoh events, small-scale emergence of magnetic flux is well associated with their occurrence, suggesting that emerging flux plays a key role in triggering transient energy release in the corona. This paper reviews multi-wavelength observations coordinated with Yohkoh SXT observations for investigating the nature of SXT transient brightenings (SXR microflares) and their associated emerging flux. Finally, Solar-B space observatory is briefly introduced as a next powerful tool for multi-wavelength investigations.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

To begin with, I would like to say a few words about the CORONAS-F mission, about what observations are carried out onboard and what is the present state of the obtained scientific data. Then, we shall briefly discuss the proposals on coordinated observations with other projects and on collaboration in data analysis.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

Latitude distribution of the solar convective zone rotation rate is studied by expanding it in a complete system of orthogonal modes (both symmetric and asymmetric relative to the equator). We find the solution to the problem of determination of the rotation rate of using helioseismic data available for the latitudes of $0^{\circ}$, $30^{\circ}$, $45^{\circ }$, and $60^{\circ}$ of one (for instance, the northern) hemisphere. The pole, $90^{\circ}$, will also be included into the above latitude list for the reason to be disclosed below. It is known that any rotation rate can always be represented by an expansion in a complete system of orthogonal vector spherical harmonics with a zero superscript (see, e.g., Varshalovich et al. 1988).To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

The quantitative relation between the brightness of the coronal green line 530.5 nm Fe XIV and the magnetic field strength is considered over the 1977-2001 period. It is found that the correlation coefficients between these two parameters calculated separately inside and outside the sunspot formation zone $\pm 30^{\circ}$ have cyclic variation and occur in anti-phase. This suggests different mechanisms of formation of the corona in the fields of small, medium, and large scales. These results can be used for quantitative verification of the corona heating models.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

Simulations of cellular magnetoconvection in a compressible fluid reveal the formation of magnetic structures with a substantial bipolar component as an inherent property of the topology of cellular flows.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

This work is devoted to the new phenomena appearing in radio emission in preflare active regions that were found with the use of radio telescope RATAN-600. The first is the complicated spectral-polarization behavior in narrow frequency range and, in particularly, the double changing of the polarization emission sign in active region at the time interval of several days before big flare. The second, the detection of regular decreasing of radio brightness radio darkening of active regions, which is also observed in a few days prior to flare [Tokhchukova & Bogod (2003)].To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

I review the talks given during IAU Colloquium 196, sometimes in a revised order to suggest certain connexions. The AU now, its definition, value and uncertainty, and its modern determination are contrasted with the situation in 1640. While there are differences, not least in the value of the AU and its error, some things have not changed. As an enduring constant we require: a correct theoretical framework, precise observations, and accurate calculations. The history and context of Horrocks' transit observations are set against the backdrop of our own sightings during the 2004 event, and our journeys to Carr House and other sites in Much Hoole.

The apparent success of the subsequent 1769 world-wide effort belied the limitations imposed by the ‘black drop’ effect, now said to have two causes: finite resolution and limb darkening. Some mysteries surrounding Henderson's determination of the parallax of $\alpha$ Centauri were dispelled, which led to a discussion of modern astrometry, both from the ground and in space. A passionate plea for continuing ground-based astrometry was followed by results from satellite observatories, in particular discordant values for the parallax of the Pleiades. A graph of parallax determinations since 1769 illustrates the steadily increasing precision reminiscent of a ‘Livingston curve,’ with improvement by an order of magnitude every 50 years. This progression is expected to continue, as the next space missions (Gaia, JASMINE) should better Hipparcos by large factors. Time on the Earth and our very definition of the second are quite naturally related to motion of the planets, and the dynamical history of the solar system.

The 19th-century transit efforts were the last gasp in a 250-year endeavour linking Kepler with his Victorian heirs: From the viewpoint of determining solar parallax the Venus transit must have had its day. Discussion of its history, though, can be expected to continue. Finally, I trace the progress in determining the value of the AU over nearly 400 years, and suggest that more rapid advancement could have been facilitated by the introduction of other techniques. The danger of sticking to one strategy for too long is perhaps the best lesson which the Venus transits have to offer.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html