Solar and Aurora Activity Chat

[Polar Maritime]

 

[Yarmy]

On 12/23/2016 at 12:56, drgl said:

http://www.landscheidt.info/?q=node/50 It tells you on that page. One method is the Layman's count. Space weather counts every singe spec (silly IMO but there you go)

It is not silly. 

The international sunspot number (produced by the SIDC) is still counted in the same way it was more than 150 years ago to maintain consistency with the past. In fact, the original telescope employed by Wolf is still used!

http://sidc.oma.be/silso/node/51

http://www.skyandtelescope.com/astronomy-news/how-astronomers-count-sunspots15022016513/

"Back when Wolf started counting sunspots, he understood that two people could look through the same telescope and see two different things. Human vision, after all, isn’t a totally consistent tool. Therefore, he came up with the idea of not only counting sunspots, but also groups of sunspots. Sunspots often cluster in families, called sunspot groups. He figured tallying the groups would make for a more accurate representation of the Sun — since 25 sunspots could mean 25 tiny ones distributed all over the place, or 25 spots in a giant cluster. So he came up with a formula like this:

sunspot number = k(10G + s),

where G is the number of groups, s is the number of individual spots (all of them, including the ones in groups), and k is some factor given to each observer based on how good their vision is."

This is the only way that makes sense, because the purpose of the count is for it to be used as a proxy for solar activity.

 

 

 

 

[jonboy]

32 minutes ago, Yarmy said:

It is not silly. 

The international sunspot number (produced by the SIDC) is still counted in the same way it was more than 150 years ago to maintain consistency with the past. In fact, the original telescope employed by Wolf is still used!

http://sidc.oma.be/silso/node/51

http://www.skyandtelescope.com/astronomy-news/how-astronomers-count-sunspots15022016513/

"Back when Wolf started counting sunspots, he understood that two people could look through the same telescope and see two different things. Human vision, after all, isn’t a totally consistent tool. Therefore, he came up with the idea of not only counting sunspots, but also groups of sunspots. Sunspots often cluster in families, called sunspot groups. He figured tallying the groups would make for a more accurate representation of the Sun — since 25 sunspots could mean 25 tiny ones distributed all over the place, or 25 spots in a giant cluster. So he came up with a formula like this:

sunspot number = k(10G + s),

where G is the number of groups, s is the number of individual spots (all of them, including the ones in groups), and k is some factor given to each observer based on how good their vision is."

This is the only way that makes sense, because the purpose of the count is for it to be used as a proxy for solar activity.

 

 

 

 

But my understanding is that with modern techniques we see sunspots of very low pixel counts being counted whereas on the layman site a spot needs to have a minimum pixel count of 360 ( I think) to be counted and it must last 24hr's this is more line with the original method

[drgl]

I find it hard to believe that a telescope used over 150 years ago would enable the naked eye to see some of the spots that "appear" on Spaceweather website! Even full screen zoomed in they are barely visible, I thought that image came from SDO so earths atmosphere eliminated also??

Edited January 5, 2017 by drgl

[Yarmy]

2 hours ago, jonboy said:

But my understanding is that with modern techniques we see sunspots of very low pixel counts being counted whereas on the layman site a spot needs to have a minimum pixel count of 360 ( I think) to be counted and it must last 24hr's this is more line with the original method

Spaceweather reports the NOAA Boulder count which is not the same as the International Sunspot Number. The methods used are similar, but the Boulder is usually 25% or so higher. Indeed, so far SIDC have yesterday down as spotless.

Both counts use several observers all over the world (anyone can volunteer and contribute), and for each observer a scaling factor is applied to account for differences in equipment, vision, etc. The better your telescope and vision, the more you will get scaled down. Moreover, if one observer sees a spot but no-one else does it won't be counted.  No-one is looking at satellite images or counting pixels. Besides, if anyone is doubting the observation abilities of astronomers of the past, they need to take a look at Galileo's sunspot drawings:

http://galileo.rice.edu/sci/observations/sunspot_drawings.html

Now his telescope was really primitive.

[jonboy]

1 minute ago, Yarmy said:

Spaceweather reports the NOAA Boulder count which is not the same as the International Sunspot Number. The methods used are similar, but the Boulder is usually 25% or so higher. Indeed, so far SIDC have yesterday down as spotless.

Both counts use several observers all over the world (anyone can volunteer and contribute), and for each observer a scaling factor is applied to account for differences in equipment, vision, etc. The better your telescope and vision, the more you will get scaled down. Moreover, if one observer sees a spot but no-one else does it won't be counted.  No-one is looking at satellite images or counting pixels. Besides, if anyone is doubting the observation abilities of astronomers of the past, they need to take a look at Galileo's sunspot drawings:

http://galileo.rice.edu/sci/observations/sunspot_drawings.html

Now his telescope was really primitive.

I agree different methods are used but for me the closes to the old numbers and thus a more direct comparison is that used by Geoff Sharp on the laymans sunspot count

[SteveB]

Second spotless day in a row, we've already had more spotless days in 2017 than in 2011,2012,2013,2014,2015 put together.

http://www.spaceweather.com/

Edited January 6, 2017 by SteveB

[drgl]

20 hours ago, Yarmy said:

 No-one is looking at satellite images or counting pixels. Besides, if anyone is doubting the observation abilities of astronomers of the past, they need to take a look at Galileo's sunspot drawings:

 

Spaceweather uses SDO?? In any case, that wasn't my point when I said silly. IMO it is silly to count a single pixel from an SDO image as a sunspot when it can't possibly be visible from earth via a telescope, or can it? It would surely take super human eyes to see that?! Anyway, whatever count you use it's spotless again today. I'm going for 50% spotless in 2017

[jonboy]

I believe 2017 will be at least 60% spotless even on Spaceweather

[Yarmy]

8 hours ago, drgl said:

Spaceweather uses SDO?? In any case, that wasn't my point when I said silly. IMO it is silly to count a single pixel from an SDO image as a sunspot when it can't possibly be visible from earth via a telescope, or can it? It would surely take super human eyes to see that?! Anyway, whatever count you use it's spotless again today. I'm going for 50% spotless in 2017

No they don't. They aren't looking at Satellite images and counting pixels. They are human beings (mostly amateurs) in their back gardens using their own telescopes.

[SteveB]

Third spotless day in a row, 5th of 2017

http://www.spaceweather.com/

[Polar Maritime]

Taken on Wednesday night. (not mine)

 

[Snowy L]

Today's update

http://www.solen.info/solar/

"Solar flux at 20h UTC on 2.8 GHz was 71.5 (increasing 0.7 over the last solar rotation). The average 90 day 10.7 flux at 1 AU was 75.7 (it seems likely that we are already within the solar minimum. Unless cycle 25 starts earlier than expected, solar minimum could last 3-4 years)"

[jonboy]

On ‎07‎/‎01‎/‎2017 at 15:43, SteveB said:

Third spotless day in a row, 5th of 2017

http://www.spaceweather.com/

now up to 6 even though the site says 4!!

[SteveB]

5 hours ago, jonboy said:

now up to 6 even though the site says 4!!

5 spotless days in a row, 7 for 2017

http://spaceweather.com/

Edited January 9, 2017 by SteveB

[jonboy]

17 minutes ago, SteveB said:

5 spotless days in a row, 7 for 2017

http://spaceweather.com/

This is copied from the 7th on spaceweather where they count 3 spotless days yet their own text says 4 so it is 6 spotless days and 8 so far this year

SUNSPOTS VANISH, SPACE WEATHER CONTINUES: As 2017 begins, one thing is clear.  Sunspots are vanishing.  So far, the sunspot number has been zero almost every day: Jan. 1st, 2nd, 4th, 5th, 6th and 7th. A close look at today's sun reveals no dark cores at all

[Yarmy]

4 hours ago, jonboy said:

This is copied from the 7th on spaceweather where they count 3 spotless days yet their own text says 4 so it is 6 spotless days and 8 so far this year

SUNSPOTS VANISH, SPACE WEATHER CONTINUES: As 2017 begins, one thing is clear.  Sunspots are vanishing.  So far, the sunspot number has been zero almost every day: Jan. 1st, 2nd, 4th, 5th, 6th and 7th. A close look at today's sun reveals no dark cores at all

It's 8 spotless days in a row on SIDC (International Sunspot Number):

Too early to say how SC25 will progress. One feature of relatively stronger cycles is that even though they have fewer spotless days in the transition period from the previous minimum, those spotless days tend to accumulate more quickly and tail off sooner. The following chart demonstrates this:

 

So you can't really tell how weak/strong the maximum will be from the current activity. That said, I do think there's a chance we are witnessing a secular change to a period of depressed activity. Time will tell.

 

[jonboy]

13 hours ago, Yarmy said:

It's 8 spotless days in a row on SIDC (International Sunspot Number):

Too early to say how SC25 will progress. One feature of relatively stronger cycles is that even though they have fewer spotless days in the transition period from the previous minimum, those spotless days tend to accumulate more quickly and tail off sooner. The following chart demonstrates this:

 

So you can't really tell how weak/strong the maximum will be from the current activity. That said, I do think there's a chance we are witnessing a secular change to a period of depressed activity. Time will tell.

 

Interestingly that last chart infers we are already in cycle 25 I would suggest we are only just entering the minimum between cycles and therefore still in cycle 24. I would not be surprised not to see any significant sustained activity before 2019 

[jonboy]

I found this bit of text on spaceweather interesting today.

SUNSPOTS VANISH, SPACE WEATHER CONTINUES: So far in 2017, the big story in space weather is sunspots--or rather, the lack thereof. So far this year, the sun has been blank more than 90% of the time.  Only one very tiny spot observed for a few hours on Jan. 3rd has interrupted the string of spotless days. Devoid of dark cores, today's sun is typical of the year so far:

So should spaceweather spotless count be 12 not 8? Either way the sun is going into hibernation

[SteveB]

8 consecutive spotless day's

http://spaceweather.com/

[drgl]

I remember the tiny dot on the 3rd, that was my point earlier in the thread. A tiny (& it was TINY!) dot observed for a few hours does not really mean that day should not be classed as spotless IMO. Anyway, we are splitting hairs, it's spotless again  Although not for much longer by the looks of it......

[Polar Maritime]

Many sighting spotted across the North last night under Kp4, 

[summer blizzard]

On 12/30/2016 at 13:46, SteveB said:

Indeed it's gone blank again, 32 day's spotless 8% spotless for the year.

http://www.spaceweather.com/

Love http://landscheidt.info/?q=node/50  Website, great that he is counting sun spots like they used to do. 22 continuous spotless day's going by the old method & cycle24 very much mirroring cycle5 the Dalton minima. Lets hope Jan 2017 can be one to remember.

I thought we were above 50 for 2016.

[Crepuscular Ray]

As ever with the Sun, it can have spots large enough even for the layman's count during solar minimum. The group near the limb is growing, although the one centre-stage is beginning to decline.

http://spaceweather.com/images2017/25jan17/hmi1898.gif?PHPSESSID=g0lllsqqvte9kmjbh3kd768of3

[Polar Maritime]

Loch Erisort, Isle of Lewis from Thursday night.