Flamsteed Astronomy Society

Is the Sun waking up again?

Public solar viewing — May 31, 2009

On May 31, 2009 the Flamsteed “Coronado Corps” volunteer team had its first outing for many months.   We arranged the session more in hope than expectation — the Sun has been deep in a minimum activity phase and is now well overdue for a return to more visible signs.  Almost no sunspots have been seen for many months.  "In our professional careers, we've never seen anything quite like it. Solar minimum has lasted far beyond the date we predicted in 2007."  (Dean Pesnell, Goddard Space Flight Center).

The Flamsteed began running public solar viewing sessions at the ROG in 2003.   The Society donated a Hydrogen-alpha solar telescope to the ROG so that the Sun could be observed safely.  The H-alpha filter blocks most of the Sun’s radiation from the telescope and only admits the red/orange light emitted by the hot Hydrogen gas.  (Never observe the Sun directly or through binoculars or a telescope without a proper solar filter!)

The last solar maximum occurred around 2001, and by 2003 there was still a great deal of activity to observe — sunspots, prominences, and filaments were quite common and easy for visitors to see through the scope.  The Sun’s activity, however, changes over a cycle of about 11 years; that is about 5 to 6 years from maximum activity to minimum.  (This is part of a 22-year cycle.  The Sun’s magnetic poles flip every 11).  By 2006 there was little to see  The Flamsteed session in November 2006 saw a couple of good prominences but no sunspots.  It is very difficult to explain to visitors what they can see when only a featureless orange ball is visible through the scope.   Since then we have only attempted a couple of sessions, while we waited for the magic combination of a good sunspot, or two, to see, and clear weather to work in.

Earlier predictions of the solar cycle expected visible activity to be building again from around 2007, with the new max in 2012-ish in time for the London Olympics, but no such luck.  New predictions now suggest more activity from 2010/11 leading to a weak maximum in 2013...  but don’t hold your breath!  We hope this discrepancy is within the ‘normal’ variation observed in previous cycles — they can vary in length from 9 to 14 years, and be stronger or weaker —  predictions now compare the new cycle with the 1928 weak max.  We sincerely hope the Sun is not entering a new ‘Maunder Minimum’; a 75 year period of very low activity between 1650 and 1725, named after the Greenwich astronomer who detected it in old sunspot records (see ‘Read More’).   The Maunder Minimum coincided with a long period of very cold weather, called the ‘Little Ice Age’.

Every rare pitiful sunspot that emerges briefly is heralded as the messenger of the new cycle. (New cycle spots have opposite polarity to the old).  At the time of writing, spot 1019 emerged after our session, and had shown promise, but was fading away again.

Nevertheless, we travel in hope!  Visitors to the ROG are always delighted with the chance to observe through a telescope, especially in daylight.  Working on the Flamsteed solar viewing sessions is very rewarding.

Fingers crossed that the Sun is waking up again now.



The Pic du Midi H-alpha Climso Coronagraph shows four small prominences for our May 31 session.  There were no sunspots.

Mike holds forth (Pic: Mike Dryland)

A good queue of visitors waits for a peek (Pic: Mike Dryland)

Dave, Tim and a group around the Coronado wait for some clouds to pass

(Pic: Mike Dryland)

Deborah does great work handing out leaflets and keeping the family groups entertained

(Pic: Mike Dryland)