Results 21 to 30 of about 5,646,026 (251)
The Astrophysical Journal Supplement Series, 2023 Angelo Secchi, an Italian Jesuit and prominent scientist of the 19th century, and one of the founders of modern astrophysics, observed the Sun regularly at the Collegio Romano in Rome, Italy, for more than 25 yr.
I. Ermolli +5 more
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The Ratio Between the Number of Sunspot and the Number of Sunspot Groups [PDF]
Geomagnetism and Aeronomy, 2017 Data from three solar observatories, Learmonth, Holloman, and San Vito, are used to study the variations in the average number of sunspots per sunspot group. It is found that the different types of sunspot groups and the number of sunspots in these groups have different solar cycle and cycle to cycle variations.
Georgieva, K. +3 more
openaire +2 more sources
Change of Sunspot Groups Observed from 2002 to 2011 at ButterStar Observatory [PDF]
Journal of Astronomy and Space Sciences, 2012 Since the development of surface magnetic features should reflect the evolution of the solar magnetic field in the deep interior of the Sun, it is crucial to study properties of sunspots and sunspot groups to understand the physical processes working ...
Sung-Jin Oh, Heon-Young Chang
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Observing And Measuring Sunspots In VIS And NIR Regions [PDF]
Engineering and Technology Journal, 2010 This study is dedicated for observing and studying sunspots in the visible andnear infrared regions. Visible and near infrared CCD solar imaging system employing5 inch reflecting telescope is used.
Mohamed Saleh Ahmed, Layale Yahya Salih
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Relative Sunspot Number Observed from 2002 to 2011 at ButterStar Observatory [PDF]
Journal of Astronomy and Space Sciences, 2012 The ButterStar Observatory at the Dongducheon High School has been working for photographic observations of the Sun since October 16, 2002. In this study, we observed the Sun at the ButterStar observatory for 3,364 days from October 16, 2002 to December ...
Sung-Jin Oh, Heon-Young Chang
doaj +1 more source
Automated McIntosh-Based Classification of Sunspot Groups Using MDI Images [PDF]
, 2007 YesThis paper presents a hybrid system for automatic detection and McIntosh-based classification of sunspot groups on SOHO/MDI white-light images using active-region data extracted from SOHO/MDI magnetogram images.
T. Colak +3 more
core +7 more sources
Extremely large flares/multiple large flares expected from sunspot groups with large area
Earth, Planets and Space, 2022 The possible occurrence of major space weather events, such as large solar flares within one hundred years, is studied anticipating their effects on our social facilities.
Shinichi Watari
doaj +1 more source
Relationship between group sunspot numbers and Wolf sunspot numbers [PDF]
Astronomische Nachrichten, 2010 AbstractContinuous wavelet transform and cross‐wavelet transform have been used to investigate the phase periodicity and synchrony of the monthly mean Wolf (Rz) and group (Rg) sunspot numbers during the period of June 1795 to December 1995. The Schwabe cycle is the only one common period in Rg and Rz, but it is not well‐defined in case of cycles 5–7 of
Li, Kejun, Liang, Hongfei
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Meridional motions of sunspots and sunspot groups
The Astrophysical Journal, 1986 Etude des positions des taches solaires et des groupes de taches determinees au Mont Wilson en lumiere blanche entre 1917 et 1983, afin d'examiner la nature des mouvements meridiens des taches et groupes durant cet ...
R. Howard, P. A. Gilman
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PRE-FLARE DYNAMICS OF SUNSPOT GROUPS [PDF]
The Astrophysical Journal, 2014 Several papers provide evidences that the most probable sites of flare onset are the regions of high horizontal magnetic field gradients in solar active regions. Besides the localization of flare producing areas the present work intends to reveal the characteristic temporal variations in these regions prior to flares.
Korsós, Marianna Brigitta +2 more
openaire +3 more sources