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Doc Willie
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Sunspot classification questions
      #5540406 - 11/26/12 02:22 PM

I am having some trouble classifying some sunspots using the Zurich classification. There are some that do not seem to fit the descriptions or the photos that illustrate the classifications.

1. A sunspot appears to be single, with a well developed penumbra. On higher magnification, it is revealed to be two or more umbrae quite close to each other. Is this still a unipolar group? What should its classification be?

2. A scattered group has the most prominent member in the middle. How does one classify that?

3. NOAA's region summary gives the classification of present sunspots, and locates them by Carrington longitude. Is there a resource that shows what the present Carrington coordinates are?


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bob71741
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Re: Sunspot classification questions new [Re: Doc Willie]
      #5540456 - 11/26/12 02:50 PM

Doc - cannot help w/questions 1&2, but have some answers for Q3; try http://www.raben.com/maps/ephemeris for current solar ephemeris and http://www.petermeadows.com/html/software.html for solar ephemeris for any date/time and more wrt sunspots.

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Doc Willie
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Re: Sunspot classification questions new [Re: bob71741]
      #5540723 - 11/26/12 05:47 PM

Helio seems to be what I need for the longitude, etc. Thanks.

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Doc Willie
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Re: Sunspot classification questions new [Re: Doc Willie]
      #5545165 - 11/29/12 09:34 AM

Nobody does sunspot classification?

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David Knisely
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Re: Sunspot classification questions new [Re: Doc Willie]
      #5545581 - 11/29/12 01:50 PM

I don't usually do, as I am more interested in their magnetic classification (Mt. Wilson) than the old Zurich class. It tells me a little more about whether an active region is likely to continue to develop and to become active in terms of solar flare potential than the Zurich class does. Clear skies to you.

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Doc Willie
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Re: Sunspot classification questions new [Re: David Knisely]
      #5547581 - 11/30/12 05:46 PM

Um, how does one identify polarity visually?

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Bob Moore
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Re: Sunspot classification questions new [Re: Doc Willie]
      #5547825 - 11/30/12 08:36 PM

Hi guys, this is s little off track but being new to solar can anyone tell me where i can find info, to get a better understanding what /i/m seeing in my images.

Thanks for any help you can give.

Bob


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David Knisely
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Re: Sunspot classification questions new [Re: Doc Willie]
      #5548158 - 12/01/12 01:19 AM

Quote:

Um, how does one identify polarity visually?




Mostly you have to rely on the Space Weather Prediction Center's bulletins or the magnetograms obtained from the various solar observatories to tell much for certain (Big Bear Solar Observatory, NSO, or NASA's SOLAR MONITOR are good sources for magnetograms if you want to do the classification for yourself). For the basic Mt. Wilson classification groups, there are a few visual clues in H-alpha as to the classification, but these are far from iron-clad as to pinning down what they really are without magnetogram data to help out:

ALPHA: A single dominant spot, often linked with a plage of opposite magnetic polarity. These are just seen as a single spot with a weak patch of plage either behind it or just ahead of it.

BETA: A pair of dominant spots of opposite polarity (Bipolar, ie: a leader (p polarity) and a follower(s) (f polarity)). Usually, the leading spot is somewhat larger and better organized than the followers in Beta groups and is a little separated from the trailing spot or trailing spot cluster. The trailer cluster or spot sometimes has a little more weak plage associated with it than the leading spot does, especially in a group that is still developing. If the spot leading the beta group as the sun rotates is smaller and more broken than the trailing spot, the group might be one known as an "inverted polarity" spot. These inverted groups usually will usually die out, or the p spot or the p polarity area behind the f spot will push westward through or past the field of the f spot, creating magnetic shear and possible flare activity until it regains its rightful place in the leading end of the group.

GAMMA: Complex groups with irregular distribution of polarities. They are somewhat irregular in form with somewhat broken features or extended broken or fragmentary form.

BETA-GAMMA: Bipolar groups which have more than one clear north-south polarity inversion line. This can sometimes be what looks like a long extended group consisting of a large leader or leaders in a group, followed by a central almost bipolar looking spot cluster in the middle, and then a more distant following spot cluster on the back end. In other cases, they are just two large clusters of sunspots very near each other that tend to have hints of local bipolar (leader and follower) structure in each cluster.

DELTA: Umbrae of opposite polarity together in a single penumbra. These groups tend to be big, and have multiple large irregularly-shaped umbrae inside of a single penumbra that is sometimes broken on the edges. The H-alpha fibrils tend to be really tortured-looking in and around Deltas, and a filament may seem to snake its way through or out of some Deltas. They also tend to be the site of some of the largest solar flares, so if one is identified on one of the bulletins, it should be watched carefully. Deltas do eventually decay after some flaring, so they may not last as long as some other spot groups.

BETA-GAMMA-DELTA: These have characteristics of all three groups and are also somewhat large and irregular. Again, they need to be watched carefully for flare activity. They also may change their classification as they decay.

Clear skies to you.


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David Knisely
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Re: Sunspot classification questions new [Re: Bob Moore]
      #5548168 - 12/01/12 01:27 AM

Quote:

Hi guys, this is s little off track but being new to solar can anyone tell me where i can find info, to get a better understanding what /i/m seeing in my images.

Thanks for any help you can give.

Bob




OK, for H-alpha observing, try this article:

OBSERVING THE SUN IN H-ALPHA

Otherwise, there are a number of decent books on the subject, as well as other sources of information. One good one is on the Space Weather Prediction Center:

http://www.swpc.noaa.gov/Education/index.html

Clear skies to you.


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Jeffrey C.
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Re: Sunspot classification questions new [Re: Doc Willie]
      #5549826 - 12/02/12 05:50 AM

Quote:

I am having some trouble classifying some sunspots using the Zurich classification. There are some that do not seem to fit the descriptions or the photos that illustrate the classifications.

1. A sunspot appears to be single, with a well developed penumbra. On higher magnification, it is revealed to be two or more umbrae quite close to each other. Is this still a unipolar group? What should its classification be?

2. A scattered group has the most prominent member in the middle. How does one classify that?





If you use higher magnification and the single sunspot splits in 2 or more umbra it would still be an unipolar group. Type A or if there is some penumbra visible type J.
For your other question it's possible that it are 2 groups instead of one.


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David Knisely
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Re: Sunspot classification questions new [Re: Jeffrey C.]
      #5550400 - 12/02/12 02:02 PM

Quote:

If you use higher magnification and the single sunspot splits in 2 or more umbra it would still be an unipolar group. Type A or if there is some penumbra visible type J.
For your other question it's possible that it are 2 groups instead of one.




If a single isolated spot has a small light bridge or two fairly symmetric umbrae inside of a penumbra, that might be unipolar (an Alpha). However, the Delta sunspot group can have more than one umbrae in a single penumbra or penumbral area and not be unipolar. Deltas tend to be large and usually have more than two umbrae that can appear rather irregular in shape. One that I saw once looked like someone had chopped up a very large umbra into at least six pieces, and it generated one of the most impressive solar flares I have ever seen. It looked like a gigantic brilliant "crack" like one sees in night-time images of flowing volcanic lavas in Hawaii. Clear skies to you.


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Jeffrey C.
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Re: Sunspot classification questions new [Re: David Knisely]
      #5550537 - 12/02/12 03:26 PM

The original question was about the Zürich classification, so done in white light without use of magnetograms. Most likely at the telescope.
So if you see a single isolated sunspot with an penumbra (J or H class) it is unipolar according to the Zürich classification.
When you used higher magnification, was there still some penumbra visible? Bad seeing can make it look like an sunspot has an penumbra.
When did you made your observation?


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David Knisely
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Re: Sunspot classification questions new [Re: Jeffrey C.]
      #5551372 - 12/03/12 01:38 AM

Quote:

The question was about the Zürich classification, so done visually without use of magnetograms. Most likely at the telescope.
So if you see a single isolated sunspot with an penumbra (J or H class) it is unipolar according to the Zürich classification.
When you used higher magnification, was there still some penumbra visible? Bad seeing can make it look like an sunspot has an penumbra.
When did you made your observation?




I'm not certain what you are talking about. Deltas are rather big and easy to notice, as they tend to have bright plage in the area as well as an active region (neutral line) filament running part way around or even through it. If I see a single well-developed leading spot (or even a pair of umbrae inside a single penumbra), and there is another smaller spot or spot cluster that is trailing it, with some weak plage around and between them, it is clearly a Beta-P group. The group is clearly bipolar. If I see a single sunspot with only plage following it, then the spot is usually unipolar (an Alpha spot). Clear skies to you.


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Doc Willie
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Re: Sunspot classification questions new [Re: Jeffrey C.]
      #5553011 - 12/03/12 10:37 PM

Quote:

The original question was about the Zürich classification, so done in white light without use of magnetograms. Most likely at the telescope.
So if you see a single isolated sunspot with an penumbra (J or H class) it is unipolar according to the Zürich classification.

When you used higher magnification, was there still some penumbra visible? Bad seeing can make it look like an sunspot has an penumbra.
When did you made your observation?




Yes, white light, visual, at the scope. Do check SpaceWeather and NOAA afterwards to confirm my observations.

On higher mags, there is still a penumbra, surrounding two or more closely packed umbras. Most of these have been classified as bipolar at the NOAA site.

Several obs over the past 2 weeks.


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David Knisely
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Re: Sunspot classification questions new [Re: Doc Willie]
      #5553246 - 12/04/12 02:02 AM

Quote:

Quote:

The original question was about the Zürich classification, so done in white light without use of magnetograms. Most likely at the telescope.
So if you see a single isolated sunspot with an penumbra (J or H class) it is unipolar according to the Zürich classification.

When you used higher magnification, was there still some penumbra visible? Bad seeing can make it look like an sunspot has an penumbra.
When did you made your observation?




Yes, white light, visual, at the scope. Do check SpaceWeather and NOAA afterwards to confirm my observations.

On higher mags, there is still a penumbra, surrounding two or more closely packed umbras. Most of these have been classified as bipolar at the NOAA site.

Several obs over the past 2 weeks.




If you have a sunspot group with dominant spot that is double (two umbrae in the same penumbra) and *no* follower spots, chances are that both the umbrae are probably of the same polarity. A bipolar group might have a double leading spot, but it will often be followed at a little distance by a trailing spot or spot cluster. In H-alpha, a newly developing group might have the trailing spots so imbedded in bright plage that they don't show up unless you de-tune the filter or observe the group in white light. The presence of a well-defined arch filament system trailing the lead spot(s) is a dead giveaway for a developing bipolar (Beta) sunspot group. Some of the trailing spots can be pretty tiny, so you do have to use high power and get good seeing to see them sometimes. The trailers also tend to be the first spots to fade away as the group decays. Clear skies to you.


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Jeffrey C.
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Re: Sunspot classification questions new [Re: Doc Willie]
      #5553303 - 12/04/12 03:33 AM

Quote:


Yes, white light, visual, at the scope. Do check SpaceWeather and NOAA afterwards to confirm my observations.

On higher mags, there is still a penumbra, surrounding two or more closely packed umbras. Most of these have been classified as bipolar at the NOAA site.





It could be that you are missing some of the smaller spots, what magnification do you use?
If you want to confirm your observations it's better to have look at observatories that still do the old Zürich classification instead of the McIntosch.
Have a look at following websites: Ukkel, Catania, Locarno, Kanzelhöhe. Kanzelhöhe and Locarno have a drawing archive so you can compare your old observations.


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