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The K7RA Solar Update


Over the past reporting week (October 13-19) compared to the previous seven-day average daily sunspot number declined from 55 to 31, while average daily solar flux dropped from 101.9 to 83.4.

Planetary A index increased from 6.6 to 19.1, and average mid-latitude A index jumped from 5 to 14.

This is the opposite of what happened two weeks ago compared to last week, when A indices decreased but solar flux and sunspot numbers rose.


The latest prediction for solar flux (from the October 20 prediction) shows these values: 75 on October 21-23, 72 on October 24, 75 on October 25-26, 80 on October 27, 75 on October 28-29, 80 on October 30, 85 on October 31 through November 5, 90 on November 6-8, 85 on October 9-11, 80 on November 12-14, 75 on November 15-19, 70 on November 20-22, 75 on November 23-25, 80 on November 26 and 85 on November 27-30.

Predicted planetary A index is 5 on October 21, then 22, 24 and 40 on October 22-24, then 44, 40 and 22 on October 24-27, 15 on October 28-30, 25 on October 31, 12 on November 1, 5 on November 2-5, 8 on November 6, 5 on November 7-10, then 10, 24, 26, 12 and 8 on November 11-15, 5 on November 16-17, then 12 and 22 on November 18-19, 35 on November 20-22, 20 on November 23, 15 on November 24-26, 25 on November 27, 12 on November 28 and 5 from November 29 to December 2.

Petr Kolman, OK1MGW, of the Czech Propagation Interest Group sent the following geomagnetic activity forecast for the period October 21-November 16, 2016

 “Geomagnetic field will be:

Quiet on November 7-8

Mostly quiet on November 3-4, 9-11, 15-16

Quiet to unsettled on October 21, November 1-2, 5-6, 14

Quiet to active on October 22-23, 29-31, November 12-13

Active to disturbed on October 24-28

 Amplifications of the solar wind from coronal holes are expected on October 22-31, November 5-6, 11-13”


Here is an article about a nearby star which seems to exhibit sunspot activity:


Another solar article, but this one regarding our own Sun:


Reader Roger Larson, KF6IVA, of Harrison, Maine says he uses an inexpensive alternative to solar telescopes called the Sunocular. A week ago he sent this message: "You can buy a special pair of binoculars (Sunoculars, 8x32 binoculars with a special coating) that allow you to observe the Sun. I can see a big sunspot headed off to the western limb, other that the Sun is featureless."

Here is the model Roger uses:

A week later he wrote: “The Sun was featureless yesterday. With these ‘Sunoculars’ you can make out large sunspots and therefore get an idea of how active the Sun is. I have seen specialized solar telescopes which would show more due to their higher magnification but they cost a thousand dollars plus.”

Here is a less expensive model from the same source, but I don’t know how much better the more expensive one is:

Here is the last correspondence from Roger, received just as I was completing this bulletin: "They work pretty well realizing that they are only good for observing the Sun. I imagine that you've looked at the Moon with binoculars, the Sun is roughly the same angular dimensions (30 arc minutes).  The Moon has a lot of features visible in 8 power binoculars, the Sun is featureless unless there's a large sunspot(s). Along the edge of the Moon you'll see some "rainbow" effects due to imperfections in the lens unless you look with expensive binoculars. Well there are a few of these rainbow effects visible in the Sunoculars no worse than any other binoculars I've used. The objective lens is coated with a material that allows ten-millionth (1 x10^-5) of the light to pass through. The Sun appears about as bright as a full Moon in them."


For more information concerning radio propagation, see the ARRL Technical Information Service at For an explanation of the numbers used in this bulletin, see An archive of past propagation bulletins is at More good information and tutorials on propagation are at

Monthly propagation charts between four USA regions and twelve overseas locations are at

Instructions for starting or ending email distribution of ARRL bulletins are at

Sunspot numbers for October 13 through 19 were 41, 38, 35, 25, 23, 24, and 31, with a mean of 31. 10.7 cm flux was 95.3, 92.8, 84.9, 80.9, 76.2, 77.4, and 76.5, with a mean of 83.4. Estimated planetary A indices were 43, 24, 11, 18, 20, 11, and 7, with a mean of 19.1. Estimated mid-latitude A indices were 30, 20, 8, 13, 12, 10, and 5, with a mean of 14.