Solar astrometry
Measuring the solar diameter with meridian transits, drift scans and pinhole instruments.
Research · Solar physics
Studying the Sun, measuring the sky
The Solar Physics Laboratory “Alessandro Cacciani” brings together solar astrometry, astronomical observation and teaching at ICRA and Sapienza University of Rome.
Eclipses & transits
Solar-radius measurements using Baily’s beads, lunar profiles and the transits of Mercury and Venus.
Stellar photometry
Observations of Delta Scorpii and Betelgeuse, alongside solar observations and occultation studies.
History of astronomy
Meridian lines, astronomical instruments and the connections between historical and modern observations.
The laboratory & its collaborations
The laboratory archive documents work led by Prof. Costantino Sigismondi, including the Clavius project, eclipse observing campaigns and measurements at the Clementine Gnomon in Santa Maria degli Angeli, Rome.
Department of Physics · Piazzale Aldo Moro 5 · 00185 Rome, Italy
Costantino SigismondiInternational collaborations documented in the archive
- IRSOL · Locarno, Switzerland
- Observatoire de la Côte d’Azur / Fizeau · Nice, France
- Institut d’Astrophysique de Paris · France
- University of Insubria · Como, Italy
- Observatório Nacional · Rio de Janeiro, Brazil
Students & alumni
Projects, observing campaigns and reports from the laboratory’s teaching archive.
2025–2026
Misure del diametro solare allo Gnomone Clementino
Pietro D’Amico
2023–2024
Osservazioni di Sirio a Piazza San Pietro
Patrizio Malloni
2023–2024
Osservazioni Astronomiche allo Gnomone Clementino
Flavio Cencioni
2020–2021
Solar meridian diameter at the Clementine Gnomon
Claudia Caldarella and Elisa Cicillini
2019
Angelo Secchi and solar studies in Santa Maria degli Angeli
Sara Bacchini, Beatrice Baschetti, Massimiliano Romanello and Luigi Bordoni
2018
Secchi and the birth of solar astrophysics
Classes 3AL and 4BL, Lyceum G. Ferraris, Rome
2017
Solar diameter from Mercury transit videos
Francesco Castiglioni and Domenico Cicogna
2016
Solar diameter from visual observations of the transit of Mercury
Felipe Cardoso
2015
Solar eclipse, transits of Venus and pinheliometer studies
Massimo Carinci, Carlos Brandt and Alessio Mimmo
2014
Differential photometry of Delta Scorpii; Nova Centauri 2013
Gabriele Ucci, Vanessa Zema, Francesco Scardino and Federico Vincentelli
2012
Betelgeuse, Delta Scorpii, solar diameter and the transit of Venus
Paola Di Mauro, Vera di Cianni, Carolina Parroni and Luca Sabatini
2011
Solar astrolabe and drift-scan observations
Giulia de Rosi, Dario Cortese and Raffaele Pontrandolfi
2010
Measuring solar diameter with eclipses
Emanuela Gizzi, Luigi Squillante and Riccardo Moriconi
2009
Comparing solar diameter measurements with Baily’s beads
Eleonora di Valentino, Maria Concetta Tringali, Daniele Caprioli, Andrea Raponi, Fabrizio Oliva and Samuele Matteucci
2008
Ptolemy and Copernicus: meridian lines
Licia Mangione
2007
Solar observation projects
Micol Benetti, Luca Naticchioni, Irene Di Palma, Alessandra Mastrobuono Battisti, Paolo Fermani and Marco Innocenti
2006
Pinhole Solar Monitor and the eclipse expedition in Egypt
Silvia Pietroni, Chiara Melchiorre and Laura Giannuzzo
2005
Baily’s beads and the Valoria la Buena observing mission
Manuela Ferrante and Pietro Oliva
2004
Asteroseismology with a photometer
Runa Antonio Briguglio, Laura Elena Nalbant and Marco Iacobelli
Selected research publications
Solar diameter, eclipse observations, lunar occultations and the Clavius project.
Relativistic implications of solar astrometry
Friedmann Seminar, Rio de Janeiro · 2011
pdf · Open documentHigh precision ground-based measurements of solar diameter in support of the Picard mission
PhD thesis · 2011
zip · Open documentGuidelines for measuring solar radius with Baily’s beads analysis
Science in China · 2009
pdf · Open documentMeasuring solar disk shape up to relativistic accuracy
Scintillation and naked-eye observations
pdf · Open documentLunar occultations and ephemerides corrections
Journal of Korean Physics · 2010
pdf · Open documentMeasuring solar diameter with solar eclipses
Conference proceedings · 2008
pdf · Open documentEuropean projects on solar diameter monitoring
With M. Bianda and J. Arnaud · 2008
pdf · Open documentSolar radius variations measured in central eclipses
Conference proceedings · 2008
pdf · Open documentMethod of calculation of solar diameter
ESOP, Drebach · 2008
pdf · Open documentSolar radius in the 2005 and 2006 eclipses
IAU Symposium 233
pdf · Open documentPinhole Solar Monitor tests in Santa Maria degli Angeli
IAU Symposium 233
pdf · Open documentSolar astrometry with pinholes
IAU Joint Discussion 12 · 2003
txt · Open documentMeasuring the angular solar diameter using two pinholes
American Journal of Physics · 2002
pdf · Open documentTeaching & textbooks
Solar physics, the history and philosophy of astronomy, ephemerides and astronomical calculations.
Gerbertus
The journal and conference series connecting medieval science, astronomy and scientific culture.
Browse the journal →Gerbert d’Aurillac & the conference archiveObservation resources
Laboratory & events archive
