FRANKY DUBOIS ' SUN PAGE
It was introduced by Rudolf Wolf in 1848. Determining Wolf numbers is a
favorite amateur observing program as it can easily be performed using
small telescopes.The Wolf sunspot number includes the number of observed
single spots s as well as that of the entire spot groups g.
Wolf multiplied the number g of groups with a factor 10 in order to express
the fact that the appearance of a new group is weighted 10 times higher
than a new spot within an existing group.An isolated spot is regarded as
a separate group. The Wolf number R is combined from spot and group numbers
according to the relation: 
When the observer determines the spot number and the Waldmeier class of a group he/she can estimate
the area of the group by multiplying the spotnumber S with a weight factor G, representing the average
area/number ratio for the group type.The new area number Ré is obtained by adding the area numbers of all groups. 
Introduced by the Norwegian Astronomical Society. The system is based on
the McIntosh Spot Classification which admits 60 possible classes.These
are arranged in a sequence giving the highest weight(60) to an Fgroup
with large symmetric penumbra and with complex spot distribution.
A single Aspot is assigneda CVweight of 1. The CVvaluesof all groups
are added and thus form the measure of spot activity.

Another sunspot number, one which considers the formation of penumbrae
as signs of high solar activity.The Pettisindex is defined as: 
In 1976, the Astronomische Arbeitsgemeinschaft Paderborn proposed a different Wolf number.
The Paderborn sunspot number IS defined as:
