21 citations · 103 across the 79 of their papers we have counts for
15 papers · 1 filter
Development and first year of results from the heliometer of Observatorio Nacional
Alexandre H. Andrei, Victor A. D'Avila, Eugenio Reis Neto +5
Recent research on global climate changes points to three distinct sources of climate disturbance: anthropogenic; natural changes in the oceans and atmosphere; and irregularities i…
Solar diameter, eclipses and transits: the importance of ground-based observations
Costantino Sigismondi
The lifetime of a satellite is limited, and its calibration may be not stable, it is necessary to continue ground-based measures of the solar diameter with methods less affected by…
Venus transit, aureole and solar diameter
Wenbin Xie, Costantino Sigismondi, Xiaofan Wang +1
The possibility to measure the solar diameter using the transits of Mercury has been exploited to investigate the past three centuries of its evolution and to calibrate these measu…
Geometrical information on the solar shape: high precision results with SDO/HMI
Xiaofan Wang, Costantino Sigismondi
The uncertainty of measurement of solar diameter is depending on the observational time scale. Full-disc images of SDO/HMI and the images from ground observations in Huairou Solar…
Solar diameter with 2012 Venus transit: history and opportunities
Costantino Sigismondi
The role of Venus and Mercury transits is crucial to know the past history of the solar diameter. Through the W parameter, the logarithmic derivative of the radius with respect to…
Christopher Clavius astronomer and mathematician
Costantino Sigismondi
The Jesuit scientist Christopher Clavius (1538-1612) has been the most influential teacher of the renaissance. His contributions to algebra, geometry, astronomy and cartography are…