Attached is a recent publication from Jose Vaquero , et al. using the American Ra number to compare to other sunspot indices and their active days.
Rodney
Attached is a recent publication from Jose Vaquero , et al. using the American Ra number to compare to other sunspot indices and their active days.
Rodney
Just to add to the current thoughts on sunspots. I was just at the current AAS meeting where Kristine Larsen had an excellent Poster paper on Elizabeth Brown who came up with her own way of recording sunspots and her own classification. Just thought I would mention it.