Most astronomical data are public. Large datasets are a mere tempting click away, and it is easy for the unwary to trip over details. Here we will highlight some sources of data which are statistician friendly and whose maintainers have made a significant effort to document their contents.
Sunspot numbers are a favorite of statisticians, because the data are the longest duration continuous astronomical dataset in existence and are a treasure trove of statistical correlations and trends. The physics of the sunspot cycle is complicated, but the statistical analyses are accessible and approachable. Yearly SSNs have been available starting from 1700, from deep within the Maunder Minimum, monthly compilations since 1749, and daily numbers from 1818. As one would expect from a multi-generational enterprise, the character of the data, how it is measured, and even what a sunspot means has changed over the centuries. The estimated SSNs are now curated by the Royal Observatory of Belgium, and the tables themselves are available at https://www.sidc.be/SILSO/datafiles. The numbers were recalibrated c.2014, and this recalibrated dataset is even available in R, post v4.5.0. Monthly sunspot numbers from 1749 to 1983 are available in the R datasets library under the name sunspots, while (recalibrated) data through October 2024 can be found in the dataset called sunspot.month.
–VLK/JCK
Maintained by the Centre de Données astronomiques de Strasbourg (CDS), VizieR (Ochsenbein et al. 2000) is a massive library of astronomical catalogs pulled in from the literature. There are currently more than 25,000 catalogs available, all in a machine-readable format, and which can be downloaded or queried in a number of ways. It is the other side of the coin to the SIMBAD database, which stores the measurements and bibliographic information for individual astronomical objects.
Link: https://vizier.cds.unistra.fr/index.gml
There is a fleet of Sun gazing telescopes, on Earth and in orbit, monitoring the solar photosphere, chromosphere, corona, magnetosphere, and the surrounding interplanetary space nearly continuously at high cadence over wavelengths ranging from radio to X-ray. In the overview by Chen et al. (2024) above, they list several sites to get the data from, see their Tables 1 and 2. Some aggregators, like the one at JSOC (http://jsoc.stanford.edu/), are more user friendly than others, and allow on the fly filtering over time, passband, spatial registration to correct for solar rotation and include up to date calibration.