Many years ago, an astronomer named Proctor wrote a book called Our
Sun, Fire, Light and Life of the Solar System. This is by no means a bad
description. The Sun formed around 4,600 million years ago, inside a
gaseous nebula. As the nebula gases condensed, the Sun became hot and
incandescent with a family of planets in orbit around it, of which the Earth is
one. Solar observing is a fascinating pastime and does not involve the need
for really large and expensive pieces of equipment.OUR STAR THE SUN
Astronomer Book
Sunspots
Viewing the Sun through an appropriate white light filter, you will
sometimes see dark patches known as sunspots on its visible surface
(photosphere). These represent regions of intense magnetic activity and
look dark simply because they’re around 1500 degrees cooler than the 6000
Celsius surrounding photosphere. Sunspots come and go according to an
approximately 11 year visual activity cycle. At solar maximum there may be
many spots, at solar minimum the Sun may be free from spots for days or
weeks at a time. People often ask if sunspots have any effect on climate and
weather. Well, all our light and heat comes from the Sun and slight changes
can have profound effects. For example, between the years 1645 and 1714
there were virtually no sunspots and the solar cycle appeared to be suspended.
This was the time of the so-called “Maunder Minimum” and the temperature
was lower in Britain than now. The Thames froze every winter and frost
fairs were held on it. Whether this was due to the Sun’s activity or not is still
the subject of debate, however in 1715 the spots returned and the situation
reverted to normal.
We do go through periods of solar warming and cooling, and these are
easily detectable though by no means catastrophic. Our own activities do have
some effect, but how much is uncertain, and recently the topic has become
increasingly political.
The Sun spins in a period of a few weeks, therefore any sunspots appear
to travel across the disc from one side to the other and it is fascinating toWe make no apology for stating the following warning as strongly as we
can – never look directly at the Sun with your eyes or through any optical
instrument unless your're using a certified, protective solar filter. PM
remembers meeting a man in his Eighties blind in one eye, who had blinded
himself looking at the Sun using a dark filter over the eyepiece and was
unable to get his eye out of the way when the filter cracked.
In some people’s view, the safest way to observe the Sun is through a small
refracting telescope, pointing the telescope at the Sun and projecting the Sun’s
image on to a screen held or fixed behind the eyepiece. This method is safe
provided you keep your eye well away from the cone of light projected through
the eyepiece. There is a real danger when using this projection method, however:
never ever leave the telescope unattended. The natural inclination on seeing
a telescope set up, especially for a child, is to look through it. If that telescope
is pointing at the Sun, the result will be immediate and permanent blindness.
Another method is to use a certified solar filter fitted over the entire open end of
your telescope. This method is described in more detail later.[1] & [2] Sunspots imaged through a 5-inch telescope protected by
Baader Astrosolar film.
[3] Full-aperture solar filter.
[4] Solar image viewed by the projection method.12