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Transit of Mercury in the Spicule Layer. Phil took this great image with his Quantum 6 Scope, Solar Spectrum etalon and PGR Camera.

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Moving forward from solar cycle 24 to 25

Time for selling...

Use this section to discuss "standard" Baader/Coronado/ Lunt SolarView/ Daystar, etc… filters, cameras and scopes. No mods, just questions/ answers and reviews.
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langleif2
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Time for selling...

Post by langleif2 » Mon Oct 14, 2019 7:41 am

I would say sell your solar gear while there is time. The average magnetic field strength in sunspot umbras has been steadily declining for more than a decade (don't know about the last years, though)

NN_Sep11_Sungraph_400px.jpg
NN_Sep11_Sungraph_400px.jpg (11.1 KiB) Viewed 462 times

Where the field is less than 1,500 gauss, spots do not appear at all. If the current trend keeps up the Sun would cross this line around 2022, after which its face would be blank in years to come (Sky & Telescope).

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krakatoa1883
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Re: Time for selling...

Post by krakatoa1883 » Tue Oct 15, 2019 9:00 am

That graph is quite old now and was much disputed at the time. Current predictions for cycle 25th are quite promising

http://sidc.oma.be/silso/
https://www.nature.com/articles/s41467-018-07690-0

so better not to sell anything for the moment.
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langleif2
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Re: Time for selling...

Post by langleif2 » Tue Oct 15, 2019 5:32 pm

Yeah, it's old data but perhaps still viable, because are the gauss measurements for the last years still declining?

Also solar seismologists should see the startup of the jet streams that will cause Cycle 25. But so far (old data), there is no trace of them in either hemisphere, as shown in the data plot below (see the right-hand corners - again old data).

Sun-ShearBelowSurface_556px.jpg
Sun-ShearBelowSurface_556px.jpg (59.36 KiB) Viewed 412 times

The observed latitudes of the deep jet streams (red and yellow) are plotted from year to year. New streams typically form at about 50° latitude (as happened in 1998 for Cycle 24), long before they cause sunspot outbreaks about a decade later. The new jet streams for Cycle 25 should have formed up in 2008 but have not started even now (old data); see the right-hand corners. (Sky & Telescope).

So are these jet streams to be seen today indicating cause of the Cycle 25?

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krakatoa1883
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Re: Time for selling...

Post by krakatoa1883 » Tue Oct 15, 2019 7:36 pm

There are signs of change coming from multiple approaches to the study of solar activity

https://iopscience.iop.org/article/10.3 ... ad1ed/meta
https://www.sciencedirect.com/science/a ... 2617307009
https://www.swpc.noaa.gov/news/solar-cy ... y-forecast

let's wait and see, anyway I'll keep my solar equipment for now :D
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marktownley
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Re: Time for selling...

Post by marktownley » Tue Oct 15, 2019 7:58 pm

Interesting articles chaps, I always enjoy reading these research papers.

I'm not selling my scopes yet either. I have a gut feeling even if there are not sunspots we will still see plage and filaments etc...
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Valery
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Re: Time for selling...

Post by Valery » Fri Oct 18, 2019 11:21 am

I do not believe that we are living exactly in the moment of solar spots disappearing forever or for a long time. All scientists need to feed their families. So, they need to create dramatic sensations. Otherwise governments will tell them - please, find another jobs.
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hopskipson
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Re: Time for selling...

Post by hopskipson » Sun Oct 20, 2019 10:00 pm

langleif2 wrote:
Mon Oct 14, 2019 7:41 am
I would say sell your solar gear while there is time. The average magnetic field strength in sunspot umbras has been steadily declining for more than a decade (don't know about the last years, though)


NN_Sep11_Sungraph_400px.jpg


Where the field is less than 1,500 gauss, spots do not appear at all. If the current trend keeps up the Sun would cross this line around 2022, after which its face would be blank in years to come (Sky & Telescope).

So what do you have to sell? With this deep minimum we're in I'll be expecting a deep discount! :lol:

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Bob Yoesle
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Re: Time for selling...

Post by Bob Yoesle » Wed Oct 23, 2019 1:01 pm

That is indeed a rather old citation, and one must take most predictions with a grain of salt. One of the most respected sources for solar information is Dr. David Hathaway, who is now retired from NASA, but who maintains an active solar prediction interest with solar physicist Lisa Upton:
We predict that Cycle 25 will be another small cycle, with an amplitude slightly smaller than (~95-97%) the size of Cycle 24. Weak cycles such as this are preceded by long extended minima and we expect a similar deep, extended minimum for the Cycle 24/25 minimum in 2020. Based on this solar cycle 25 prediction, we expect that coming minimum last through the end of 2020 or beginning of 2021. Similarly, we expect that the Cycle 24/25 minimum will include extended periods of spotless days throughout 2020 and into 2021. Details about this predictions can be found in this paper.
See: http://solarcyclescience.com/forecasts.html
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