Procedure for determining
Sunspotregions and their Classifications

Observing by Projection, the image size should be at least 6 inches (15 cm)
Observing by Direct Vision, the magnification should be at least 100x

Once classifications of sunspotregions are ready to be performed, one must assure
how many sunspotregions are present that day.
Next thing to be assured is how many sunspotregions on each hemisphere.
Remember the 10° (heliographic degrees) distance rule.
If regioncounting for separate hemispheres is not planned, this may be skipped.

Starting from the northern hemisphere, west to east, then southern hemisphere, west to east,
one should first determine

a) the Unipolarity or Bipolarity

b) the (first) Zürich-letter
    -is it A or H (Unipolar) ?
    -is it B, C, D, E or F (Bipolar) ? (C is Bipolar one side)

c) the (second) first McIntosh-letter
    -is it a single spot ? (x)
    -is the leader spot a rudimentary spot ? (r)
    -does the leader spot have penumbra ?
    -if a penumbra, is it assymmetric or is it symmmetic ? (a, s, k, h)
        -is the leader spot less than 2½ heliographic ° ? (a, s)
        -is the leader spot greater than 2½ heliographic ° ? (k, h)

d) the (third) second McIntosh-letter
    -is it a single spot ? (x)
    -is the spotted region open, i.e. no spots between leading and preceding spots ? (o)   
    -is the spotted region intermediate,
        i.e. spots between leading and preceding spots ? (i)
    -is the spotted region compact,
        i.e. penumbraspots between leading and preceding spots ? (c)

After having answered these questions by yourself, the classification should be ready.
You will now procede onto the next sunspotregion, and continue so until you have finished.

You will now have three-letter codes for all sunspotregions visible on that day.

CV-Helios Network in October 1998/May 2006/Oct 2017

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