Abstract

Should We Try to Re-Construct the American Relative Sunspot Index (Ra)?

Author(s): Howe R

The new correction of the international sunspot number (ISN), called the Sunspot Number Version 2.0, led by Fredric Clette (Director of the World Data Centre [WDC]-SILSO), Ed Cliver (National Solar Observatory), and Leif Svalgaard (Stanford University), nullies the claim that there has been a Modern Grand Maximum. This comes from the International Astronomical Union (IAU) press release, August 2015 (http://www.iau.org/news/pressreleases/detail/ iau1508/). This ISN reconstruction raises some questions for the AAVSO: should we try to re-construct the American Relative Index (Ra) to go along with the ISN reconstruction (Clette et al)? Shapley's method with k-factors (http://iopscience.iop.org/article/10. 1086/126109/pdf) is a statistical model that agglomerates variation due to random effects such as observer and xed effects after seeing the condition. The raw Wolf averages and calculated Ra have used the Shapley method since 1949. If the AAVSO decides to re-construct the American Ra Index, then it is important to compare the newly digitize data back to 1947 and up to 2010 from two AAVSO observer's Herbert Luft and Thomas Cragg (Vaquero et al). These archives exist at AAVSO HQ in di erent formats of raw observations from these two observers over the past 70 years