Sunday, 18 November 2018

More Signs of Cycle 25? - 18th November

Sunday mornings HMI image shows active region 2727 has developed a bit as it edges closer to the limb with a well developed bipolar spot group giving a sunspot number of 13.  Polar faculae are visible at both poles and at northern mid latitudes a very small couple of pores are visible.  This is visible on the AIA1700 image a region of brighter faculae.

And looking at the Gong image from Learmouth there is a brighter patch visible in Ha wavelengths.

While this activity from cycle 25 is not large scale at the moment it is clearly making itself visible and is worth monitoring in the days and weeks ahead.  Looking on the SOHO image it looks like a bit more activity may round the limb in the next couple of days.

Saturday, 17 November 2018

AR12727 - The Last Sunspot of Cycle 24? - 17th November

The current HMI image is typical of solar minimum.  On the solar equator there is active region 12727, quite possibly the last sunspot grouping of cycle 24.  Magnetic bands on the solar equator are slowly cancelling out with this activity; the active region is also preceded by a patch of plage closer to the limb.  Polar faculae are also visible as bright points, here there are coronal holes currently too.
In the last couple of solar rotations there have been signs of activity in northern higher latitudes on our star that showed reverse magnetic polarity.  This reversal in polarity is what differentiates solar cycles.  

Given that cycle 24 was a double peaked, with the northern hemisphere preceding the southern hemisphere, it is rational to assume that we should start to see the first signs of cycle 25 in the solar northern hemisphere.  Indeed only a week ago a small emerging flux region recently had a few small pore spots that had reversed polarity compared to cycle 25.  Pretty much all of the solar models are predicting cycle 25 will be weaker than 24 with a lower average sunspot number.  

The international sunspot number forecast from the Royal Observatory of Belgium made at the start of this month suggests we will see an uptick in solar activity as cycle 25 kicks in early in 2019.  I would speculate that given these double peaked solar cycles and that cycle 24 had the northern hemisphere peaking over 3 years before the southern hemisphere, with cycle 25 forecast to be weaker that it may well be that the frequency of the hemispherical peaks may well be longer in between.  In which case the activity of recent rotations is indeed cycle 25 activity.   It will be interesting to see how the ROB updates it's next prediction early in December.  It could well be that we are already seeing the uptick in graph they are predicting.

Monday, 12 November 2018

Ha Full Disk - 11th November

It's been a while with one thing or another since I last managed to get some solar observing in, however Sunday afternoon offered some low altitude sun to look at.  While the disk is at first sight comparatively quiet it indeed tells a story; the small emerging flux region mid disk is the last relics of cycle 24 throwing out magnetic flux, however the northern polar crown marks the boundary of the northern jet stream where cycle 25 will kick off, and near the limb on the right hand side it is possible to see the remnants of a small spot with reversed polarity, typifying it to be the next solar cycle.  The shots were taken with double stacked Lunt 50 etalons and the PGR Chameleon 3 camera.  The proms below looked great visually in single stack mode.