DEFINING SUNSPOTCLASSIFICATIONS
AND THE QUESTION REGARDING COMPACT SUNSPOTGROUPS
On the 31st May 1999 I had a question from one of our observers
regarding the compact sunspotgroups.
Many have wondered whether a class Cgroup may be of compact
distribution.
This made CVHN go to Patrick S. McIntosh to clarify the problem.
31stMay 1999,
20:49 UTC1
Dear Mr McIntosh,
As a leader of
the CVHelios Network I recently received the question
whether a Cgroup can achieve the classifications:
CAC
CSC
CRC
CKC
CHC
I was hoping you could verify this for me, please.
The modified
Zürich/McIntoshclassifications are supposed to contain
60 defined classes. I thought I knew which ones these were,
but would also like to ask you if you have a complete
listing.
Thanks in advance.
Best regards,
Kjell Inge
Malde
Director
CVHelios Network

Reply:
Compact SpotGroup types
June 3, 1999 3 PM Mountain Daylight Time
Dear Mr. Malde,
For instructing observers in the CVHelios Network:
Compact sunspot group interiors are defined only for the
groups which
form penumbra on both leader and follower spots; i.e. Classes D,
E and F.
Furthermore, the largest spot must have mature penumbra. These
groups
become compact when at least one of the spots between the leading
and
trailing spots is strong enough to have formed mature
penumbra.
Some groups may
form two or more penumbral masses in the leaderpolarity
area, making it difficult to assign the classification, but there
is no
quantitative guidance to give for these situations. Using
measured
polarities or inference of polarity from the Halpha structure
makes it
easier to apply the classification.
From my 1990 Solar
Physics paper, "The Classification of Sunspot Groups",
I give you Tables I and II:
TABLE I
Logic Sequence for
determining
McIntosh sunspot types
Unipolar or
bipolar?
Penumbra or no penumbra?
Penumbra on one end or both ends?
Length of group?
Rudimentary or mature penumbra?
Symmetric or asymmetric largest spot?
NS diameter of largest spot?
Spots between leader and follower?
Mature penumbra in interior?
TABLE II
Allowed types of groups in McIntosh sunspot classification
Class  Penumbra:largest spot  Distribution  Number of types 
(A)  (x) 
(x) 
1 
(B) 
(x) 
(o i) 
2 
(C) 
(r s a h k) 
(o i) 
10 
(D E F) 
(r) 
(o i) 
6 
(D E F) 
(s a h k) 
(o i c) 
36 
(H) 
(r s a h k) 
(x) 
5 
Total allowed types: 60
I will copy this
note to the leadership of the Solar Section of the
Association of Lunar and Planetary Observers.
Respectfully yours,
Patrick S.
McIntosh
HelioSynoptics and
McIntosh Squared Graphics
3885 Paseo del Prado
Boulder, CO 803011527
3034445880
FAX: 3034400102

This email was received on 4th June 1999 and is in full
understanding
with the classificationtabulation being the basis for
Classification Values
back in August 1981, and that has the following criteria:
1st letter 
2nd letter 
3rd letter 
A: 1 group 
x: 3 groups 
x: 6 groups 
B: 2 groups 
r: 9 groups 
o: 21 groups 
C: 10 groups 
a: 12 groups 
i: 21 groups 
D: 14 groups 
s: 12 groups 
c: 12 groups 
E: 14 groups 
k: 12 groups 

F: 14 groups 
h: 12 groups 

H: 5 groups 
D, E and F make 42
groups, as outlined above (6 and 36).
The total is: 60.
The listing below is the complete given Classification Values:
Axx=1 Bxo=2 Bxi=3 Hrx=4 Cro=5 Cri=6 Hax=7 Cao=8 Cai=9 Hsx=10 Cso=11 Csi=12 Dro=13 Ero=14 Fro=15 Dri=16 Eri=17 Fri=18 Dao=19 Eao=20 Fao=21 Dai=22 Eai=23 Fai=24 Dso=25 Eso=26 Fso=27 Dsi=28 Esi=29 Fsi=30 Dac=31 Eac=32 Fac=33 Dsc=34 Esc=35 Fsc=36 Hkx=37 Cko=38 Cki=39 Hhx=40 Cho=41 Chi=42 Dko=43 Eko=44 Fko=45 Dki=46 Eki=47 Fki=48 Dho=49 Eho=50 Fho=51 Dhi=52 Ehi=53 Fhi=54 Dkc=55 Ekc=56 Fkc=57 Dhc=58 Ehc=59 Fhc=60
CVHelios Network 4th/14th June 1999/3 May 2006/21 Oct 2017
email:
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