Last week's propagation bulletin talked about the quarterly averages of
daily sunspot numbers, and trying to determine the bottom of the solar
cycle. Carl Luetzelschwab, K9LA mentioned that there haven't been any
sunspots from a new solar cycle yet (they switch magnetic polarity) and
referred to an interesting paper that talks about the bottom of the last
cycle. You can read it off the web at,
http://www.sec.noaa.gov/info/SumSept.html. Carl highlighted the paragraph under Solar Activity, in which Karen Harvey
talks about the various factors that come into play when trying to
determine the minimum between the last and the next sunspot cycle. Not only
must the sunspot numbers be low, but for a new cycle to be observed there
must be a transition to a majority of new-cycle spots compared to a
minority of sunspots from the old cycle. I believe the next Solar Cycle
Prediction Panel meeting is in spring 2006, so perhaps we'll know more
then. Graham Rogers, VK6RO wrote to say that he thinks of the bottom of the
cycle when the solar flux reaches 66.
