January 2000 - How
to observe the Sun - John Smith
For
Sunlovers January's meeting was a must, as we had John Smith
give a very good talk on "How to observe the Sun". I hadn't
realised beforehand, but John is / has been chairman of the
SPA Solar section on and off for years, and also assists the
current BAA Solar Section Director too - so Malcolm had
definitely had a good eye for a speaker.
John
not only gave examples of how to observe the Sun, and went
into the safety aspect - as you would expect, but he also
showed with slides some of the more hidden dangers of solar
work.. like broken eyepiece filters, torn mylar, and melted
telescopes! Melted telescopes ? Yes you did read that right,
not many people realise it but a large number of the smaller
department store telescopes have plastic optics, hence when
they heat up.. they melt, or even catch fire. Quite
frightening really.
As
John rightly said, projection is the only completely 100% safe
way of viewing the Sun, and even then you have to be careful
that no kids look up the projection beam, if you're showing
the public. That said, it is also commonly the easiest way to
observe in great detail - as I can vouch for, and
photographing the projected image is very simple and can be
done with an ordinary camera. For best results however, John
explained that the projection screen should be shaded from the
direct Sun, or if possible, partially enclosed in a box of
some kind, as this enhances the contrast.
John
then went on to show a number of nice images in the visible
spectrum, and also showed some of the X ray images taken by
both SkyLab and Soho, which we well received.
After
his talk the questions flowed, and I saw that even during the
tea break he didn't get much of a rest !
If you
have any outstanding questions, please do come forward and ask
me, Kev. Solar work is something that I've done for years and
its the mainstay of my Astronomy. Got the books, made the
play, taken the photo's and the CCD images (see
alt.binaries.pictures.astro newsgroup ). Further
solar observing tips