Acta Astrophysica Taurica

The forthcoming solar cycle (SC) 25 was believed to be rather low when the sunspot number (SN) is used as a measure of the activity level. The most popular prediction was made by the NOAA/NASA Solar Cycle 25 Prediction Panel in 2019, including works based on dynamo-type models. However, we discovered that the height of SC25 could be high, using different observations for measurements of the level of the polar-region activity above the limb at high latitudes several years before the start of SC25 and also after its beginning in 2020. The polar-region activity, which we consider, seems to be related to the polar coronal-hole (CH) activity, and it was significantly higher before SC25 than before SC24. It is also possibly reflected in the so-called chromospheric prolateness observed at solar minimum. Accordingly, we suggest that SC25 could indeed be significantly higher than SC24, which was a very low SN cycle

The Lyman Alpha Imaging-Monitor Experiment (LAIME) for TESIS/CORONAS-PHOTON

International audienc

The Lyman Alpha Imaging-Monitor Experiment (LAIME) for TESIS/CORONAS-PHOTON

International audienc

The Lyman Alpha Imaging-Monitor Experiment (LAIME) for TESIS/CORONAS-PHOTON

International audienc

Analysis of broad-band H

Context.Daily broad-band full-limb Hα images of the inner corona were obtained during solar cycle 23 (1994–2005) using the 15 cm Pic-du-Midi coronagraph. Aims.We want to automatically extract the properties and evolutions of the observed cool HI coronal structures over a wide range of sizes and light fluxes, from small jets and/or spikes to large prominences. Methods.A tool was developed to process the complete set of stored images. This paper describes the recognition techniques implemented in our software and discusses its use. It includes the removal of the parasitic diffraction ring produced by the set of different occulting disks used throughout the year. Results.We present and discuss selected results from a statistical analysis of the occurrence of parameters characterizing the observed structures applied to a large sample of observations. It illustrates the capabilities of this software when applied to our database. Strong asymmetries of the activity level over the solar poles become evident, confirming similar results from previous works. We also discuss the distribution of relative light fluxes of these structures over a wide range of sizes. Conclusions.The complete series of FITS and calibrated images, the list of the detected structures, and their geometric and luminosity evolutions are stored in the BASS2000 solar database catalogue (http://bass2000.bagn.obs-mip.f

A possible E-W asymmetry of the coronal emission line intensities and K-corona brightness

The analysis of the daily measurements of the coronal green and red line intensities as well as the K-corona brightness, which have been collected by the Pic-du-Midi Observatory, for the time period 1944-1974, has revealed some very interesting features. North-South (N-S) asymmetries for all these coronal intensities are confirmed again for this time period. The main point of this analysis is a strong evidence of longitudinal distribution of the coronal intensities as derived from the data record. In our effort to confirm this asymmetry, we have examined the yearly and monthly distribution of the asymmetry coefficient in each solar quadrant showing that the northeast (NE) quadrant appears the most active of all. We have also examined the intensity ratios measured at the East and West solar limbs which is continuously greater than the unit. A seasonal variation of this ratio has also been reported with a maximum during the winter period and a minimum during the summer period. © 1994 Kluwer Academic Publishers

Analysis of broad-band H? coronagraphic observations

International audienceContext: Daily broad-band full-limb H? images of the inner corona were obtained during solar cycle 23 (1994-2005) using the 15 cm Pic-du-Midi coronagraph. Aims: We want to automatically extract the properties and evolutions of the observed cool HI coronal structures over a wide range of sizes and light fluxes, from small jets and/or spikes to large prominences. Methods: A tool was developed to process the complete set of stored images. This paper describes the recognition techniques implemented in our software and discusses its use. It includes the removal of the parasitic diffraction ring produced by the set of different occulting disks used throughout the year. Results: We present and discuss selected results from a statistical analysis of the occurrence of parameters characterizing the observed structures applied to a large sample of observations. It illustrates the capabilities of this software when applied to our database. Strong asymmetries of the activity level over the solar poles become evident, confirming similar results from previous works. We also discuss the distribution of relative light fluxes of these structures over a wide range of sizes. Conclusions: The complete series of FITS and calibrated images, the list of the detected structures, and their geometric and luminosity evolutions are stored in the BASS2000 solar database catalogue (http://bass2000.bagn.obs-mip.fr) and are made publicly available. The H? HI structures observed over the limb of the sun present statistical properties of great interest for understanding its eruptive activity

Preliminary results from the March 29, 2006 total eclipse observations in Egypt

International audienc