Parallel Group and Sunspot Counts from SDO/HMI and AAVSO Visual Observers (Abstract)

Volume 43 number 1 (2015)

Rodney Howe

3343 Riva Ridge Drive, Fort Collins, CO 80526; ahowe@frii.com

Jan Alvestad

Vigdelsvn. 637B, 4054 Tjelta, Norway; jan@solen.info

Abstract

(Abstract only) Creating group and sunspot counts from the SDO/HMI detector on the Solar Dynamics Observatory (SDO) satellite requires software that calculates sunspots from a “white light” intensity-gram (CCD image) and group counts from a filtered CCD magneto-gram. Images from the satellite come from http://jsoc.stanford.edu/data/hmi/images/latest/ Together these two sets of images can be used to estimate the Wolf number as W = (10g + s), which is used to calculate the American Relative index. AAVSO now has approximately two years of group and sunspot counts in its SunEntry database under SDOH observer Jan Alvestad. It is important that we compare these satellite CCD image data with our visual observer daily submissions to determine if the SDO/HMI data should be included in calculating the American Relative index. These satellite data are continuous observations with excellent seeing. This contrasts with “snapshot” earth-based observations with mixed seeing. The SDO/HIM group and sunspot counts could be considered unbiased, except that they show a not-normal statistical distribution when compared to the overall visual observations, which show a Poisson distribution. One challenge that should be addressed by AAVSO using these SDO/HMI data is the splitting of groups and deriving group properties from the magneto-grams. The filtered CCD detector that creates the magento-grams is not something our visual observers can relate to, unless they were to take CCD images in H-alpha and/or the Calcium spectrum line. So, questions remain as to how these satellite CCD image counts can be integrated into the overall American Relative index.