Page 83 - BBC Sky at Night Beginners Guide to Astronomy - 2017 UK

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THE CORONA

The amazing sight of the Sun’s outer atmosphere, the corona,
only becomes visible to us on Earth at totality – the height of a
total solar eclipse. Of course, the corona is always there, it is
simply that its delicate pearly-white structure is usually drowned
out by the brightness of the Sun and our daytime sky. Views of
the corona can also change quite dramatically depending on
how active the Sun is; its shape is infl uenced by the vast solar
You can observe the Sun safely magnetic fi elds.
by spending just a few pounds During totality, it is the corona that defi nes the eclipse for
on a pair of solar eclipse glasses many people, and it is only during this darkest part of a solar
eclipse that you don’t need special equipment or eye protection
to marvel at it.
The extent of the corona
can be seen during a
total solar eclipse

SOLAR SAFETY

Solar observing is the one time that astronomy poses a real risk of physical injury.
Here’s how to do it safely…ely…

SOLAR CARDBOARD SUN SOLAR FILTERS PERSONAL SOLAR
PROJECTION PROJECTOR These glass or fi lm coverings TELESCOPE
All you need is a piece of These kits are simply a small fi t completely over the light- The Personal Solar Telescope
white card, onto which you telescope and mirror that gathering front end of the (PST) is made to reveal one
project the image of the Sun projects an image of the Sun scope, stopping all heat and specifi c wavelength of light
from your scope or binoculars. onto a white screen on the virtually all light from the Sun and can show much more than
You could also fi x another inside of the box. It will show entering the scope. Good your naked eye will see with
piece around the front end of much the same views as the for viewing sunspots and fi lm or glass fi lters. Good for
the scope to create a shadow solar projection setup – great granulation. prominences, active regions,
around the projection. Good if you don’t have a scope. Cost: fi lm fi lters from fi laments and faculae.
for eclipses and sunspots. Cost: from £49 £40, glass fi lters Cost: from £480
Cost: free from £70

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