The June 2020 Eclipse Festival of Frequency Measurement

Ionospheric dynamics during solar eclipses are of scientific interest because they provide an opportunity for a controlled experiment: unlike geomagnetic storms or solar flares, their effect on solar inputs to the ionosphere is known ahead of time. Eclipses' scale, short duration and visual display make them ideal for citizen science observations, and inexpensive computing hardware makes it possible to conduct these observations with greater scope and precision than ever before. A global citizen science experiment was carried out during the annular solar eclipse of June 21, 2020 in which an international volunteer base of amateur radio operators and shortwave listeners collected Doppler shift data from time standard stations to measure the eclipse's impact on the bottom side ionosphere. Convened in less than a month, this experiment offered valuable lessons for future eclipse observations and showed what can be accomplished with distributed instrumentation managed by a large team. It also served as a pilot study for the low-cost Personal Space Weather Station (PSWS) project of the Ham Radio Science Citizen Investigation (HamSCI) collective. The findings of this effort, both scientific and logistical, will be discussed in the context of the PSWS and future eclipse experiments.