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Astronomy Should you wish to contact the
society or require general information please contact ASTRA
using the following Email address: Should you encounter any problems
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email: Airdrie Public
Observatory The Observatory sits atop Airdrie
Public Library, which is itself situated in the town centre.
Although town lights do act to block out the dim light from
the stars, it is surprising that much can still be seen
(although the recent introduction of white-light
church-illumination has been a real killer). The telescope
itself is brass-tubed, with a six-inch diameter lens at one
end, and was made by the noted telescope maker Thomas Cooke
(1807-1868) as a scientific instrument. Indeed, a seven-inch
lens telescope of Cooke's was used by Charles Piazzi Smyth,
Astronomer Royal for Scotland from 1845-1888, to test how
good Tenerife was as an astronomical site. Being of long focal length, the
Airdrie telescope is ideally suited for planetary work. From
Earth, the planets appear as ``wandering stars'', but
through the telescope, they are resolved into distinct
worlds. The dust storms on planet Mars, the phases of planet
Venus, the mountains on our own Moon, the splendid rings of
planet Saturn, and the famous turbulent red-spot of planet
Jupiter -- all can be easily seen through the Airdrie
telescope. More historically, one can also see the four
major moons of Jupiter -- the moons that Galileo saw in 1609
and were a cause of him being brought before the
Inquisition. It is estimated that around half the
stars in our Galaxy are double or multiple systems. From
Earth, each system appears as one star. Through the
telescope, many of these double stars can be resolved into
two stars; over many years the orbital motion of one around
the other can be detected. Perhaps the most beautiful double
star is Albireo, in the constellation of Cygnus the Swan.
With the unaided eye, it appears as a dim blue-white star,
but through a telescope it is resolved into two stars, one
blue, the other a striking yellow. There are many objects in the sky
that can only be seen through a telescope; consequently,
they are known as deep sky objects. These objects range from
the more compact planetary nebulae, globular clusters, and
galaxies (the so-called ``island universes'') to the more
spread-out open clusters and diffuse nebulae. A catalogue of
the brighter of these objects, compiled by Charles Messier
(1730-1817), helps one to point the telescope towards the
right patch of sky. One can be blinded temporarily by
strong sunlight; looking at the Sun through a telescope can
blind you for life, by frying your eyeball. To view the Sun
safely, we use the telescope as a projector: sunlight comes
in one end and is projected onto a small, white screen fixed
a foot or so away from the telescope eyepiece. Superposed on
the white circle of the Sun are black areas known as
sunspots. These are magnetic regions on the Sun; the strong,
local magnetic field of the spot obstructs the heated plasma
from reaching the surface at that point, and so sunspots are
a few thousand degrees cooler than the 6000-degree surface
temperature of the Sun. Solar observing is a constant
feature of the Observatory Open Days. Comets
and Meteors Beyond the orbit of Pluto there is
believed to be a spherical cloud of comets, the Oort Cloud,
encircling our Solar System. These comets are best described
as dirty snowballs. As a comet approaches the Sun, the Sun's
heat boils off its outer layers, causing it to leave behind
a trail of dust and gas that has become known as the comet's
tail. As Earth passes through this cometary debris, the tiny
pieces of dust completely burn-up in the atmosphere as
meteors (or ``shooting stars''). Sometimes it is better to
watch these objects with the naked eye, especially the
meteors, but both these fleeting objects can be viewed
through the telescope and photographed for posterity. Away
from the telescope, one can learn the patterns of stars that
make up the constellations, identify which of the ``stars''
are actually planets, observe the changing phases of the
Moon and, hopefully, catch glimpses of comets and meteors.
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