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 C-group may be of compact distribution.
This made CV-HN go to Patrick S. McIntosh to clarify the problem.

31stMay 1999, 20:49 UTC-1
Dear Mr McIntosh, 

As a leader of the CV-Helios Network I recently received the question
whether a C-group can achieve the classifications: 

CAC
CSC
CRC
CKC
CHC

I was hoping you could verify this for me, please. 

The modified Zürich/McIntosh-classifications 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
CV-Helios Network
-----------------------


Reply:

Compact SpotGroup types

June 3, 1999 3 PM Mountain Daylight Time

 
Dear Mr. Malde,

For instructing observers in the CV-Helios 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 leader-polarity
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 H-alpha 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?
N-S 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 80301-1527
303-444-5880
FAX: 303-440-0102

------------------------------

This e-mail was received on 4th June 1999 and is in full understanding
with the classification-tabulation 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


CV-Helios Network 4th/14th June 1999/3 May 2006

e-mail: w e b m a n a g e r @ c v - h e l i o s . n e t
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