Stretch of Spotless Days

[The Novitiate]

On your 'Home Page' under the 'Space Weather Facts' you list the number of spotless days as 39.  When I check the SILSO site of the Royal Belgium Observatory they list the last sunspot occurring on November 13, 2019.  Their Stretch of Spotless days is 26.  Could you identify the data source for your Spotless Numbers?

   --The Novitiate

[Vancanneyt Sander]

The data from the facts module comes from SWPC and not SILSO. 

On November 13th SWPC didn't counted region 2752 as a new region that had any sunspot and didn't register a sunspot number for that day. The spot was very short-lived and SWPC probably decided not to count it. SWPC did say there was a new region, but decided that it hadn't any spots left when they published their data and thus had a Sunspot number of 0 with 0 spots counted. SILSO however did count it as a region with 1 spot. That's why there's a difference.

Quote

IA. H-alpha Plages without Spots.  Locations Valid at 13/2400Z Nov
Nmbr  Location  Lo
2752  S23E56   286

 

[The Novitiate]

Thanks for you clarifying the details.

I remember looking at 2752 on the SDO Magnetogram and searching for it on the Intensitygram-Colored, even at 4096 pixels, not really seeing a spot.  It is likely best to side with the SILSO call...  though my gut sides with SWPC.

Thanks again  --ejd