as·tron·o·my ( P ) Pronunciation Key (-strn-m)
n. pl. as·tron·o·mies
1. The scientific study of matter in outer space, especially the positions,
dimensions, distribution, motion, composition, energy, and evolution of celestial bodies
and phenomena.
2. A system of knowledge or beliefs about celestial phenomena: the various astronomies of
ancient civilizations.
3. The branch of physics that studies celestial bodies and the universe as a whole.
Looking at it and thinking about it is studying it. People have been studying the
heavens for at least one hundred thousand years, probably longer. The sky fascinates
and draws us upward towards it.
The Sun The Moon Mercury Venus Mars Jupiter Saturn Uranus Neptune Pluto Asteroids Comets
The Milky Way Galaxies The Local Group The Creation
So, do you want to take a closer look?
Buying a Telescope
One of the first questions a beginner will ask is "What sort of telescope should I
buy". Buying the right telescope for you depends upon what you want to use it
for. If you want to photograph galaxies or nebulae you will need a solid
motorised German Equatorial Mount that tracks accurately. If you want your children
to see the stars then a light, cheap pair of good quality binoculars may be best.
For the beginner, who is not interested in photography, the best choice will be either a
set of binoculars or a Dobsonian mounted Newtonian telescope.
Binoculars
Often the best telescope for the beginner is a pair of binoculars! Many people will
ignore this advice because "they just want a telescope".
With a set of binoculars you can walk outside and take in the grandeur of a half dozen
fine objects and then go back inside for a warm drink, all in less time than it will take
for a beginner to set up his telescope. Using binoculars lets you quickly explore
the sky. You will soon learn what's where up there.
The view through a set of binoculars will be superior, in almost every way, to a
department store telescope of the same price. With care you can buy a good set of
binoculars for less than $US 100. You cannot buy a good telescope for less than $US
300.
A good set of binoculars is light, easy to target, and gives you a bright and very wide
field of view that is not upside down or back to front (like in a telescope).
Knowing where you're aiming is simple. You use two eyes instead of one, so the view
is more natural. Your brain will get data from both eyes.
The best ones for viewing the stars and the moon are known as "8x50
binoculars". This means they have a magnification of eight times (x8) and the
front lenses are 50 mm diameter.
For young children you should choose a set that is 6 x 40. This gives kids lower
magnification (so the view doesn't wobble around so much) and less weight to make it
easier for them to lift & use.
The lower the magnification the less the view will wobble around. The wobble or
shake is caused by your arms and hands shaking as they do naturally. Everybody does
it but high magnification makes viewing difficult. For adults you will want a
magnification of at least x6, preferably x8, and no more than x10.
Choose a lens diameter of 50 mm. Any more and the weight of the binoculars
becomes a problem (more shaking and wobbling), any less and you don't get as much light.
If you go above x8 magnification you will start needing a tripod or something to rest
the binoculars on to keep them steady. The extra magnification will mean that
the normal shaking of your arms & hands will cause the object you're viewing to wobble
around far too much for long term pleasant viewing.
The views of the moon and of star clusters through 8x50 binoculars are amazing.
8 x 50 binoculars are a wise investment even if you do decide to get a telescope.
A Dobsonian Mounted Newtonian Relector Telescope
Bang for dollar you cannot go past an 8" (203mm) Newtonian reflector telescope on a
Dobsonian Mount. You can buy one of these for $US 500. Eight inches of
aperture will collect a LOT of light and will let you see a lot of STUFF. An 8"
(203mm) dob collects four times more light than the typical department store Newtonian
telescope - these are usually 4" (100mm).
A German Equatorial Mount (GEM) is useful ONLY for good tracking. That's its
purpose. Why pay for it if you don't need it. Dobs are cheap because
they are not as complex to manufacture as GEMs. A GEM has more bits. A Dob is
simple and consists of the telescope tube on what is basically a turntable. Using
the Dobsonian you will aim and track by tucking the scope under an arm or holding its
handle and turning it slowly. It is MUCH easier than twisting the wretched cables
on a GEM. Most GEMs do not come with motors, you would have to pay hundreds more if
they did. Use the money you save (by not buying a GEM) to buy yourself a bigger
mirror. So buy a Dob.
A Good Quality Refractor
OK, Ok, some astronomers just absolutely love refractors. A refractor uses
a glass lens at the front of the telescope to collect its light. The main advantage
for the beginner with a refractor is its relatively compact size (making it very
portable). Its main disadvantage is also its size. It collects less light than
your Dob. You will still need a tripod to put a refractor on but there's no need to
buy a GEM mount. Usually an Alt-Azimuth mount will be enough. I am
thinking about buying either the Orion Express or the Orion ED80.
Defending the Department Store Telescope
They are good because they get people interested. They give people,
especially kids, a start. It's just that the quality is generally not good.
Also because of the way the scopes are marketed the buyers don't know what they're
getting. Most of these telescopes get bought for Xmas and very quickly get relegated
to the back of the garage, unused and collecting dust. If you can buy your first
telescope from a proper telescope shop (not from a camera shop or from a department store
but from a real telescope shop) then do it. You'll pay a little bit more but you'll
get good advice and the quality will be a lot better. You (or the kids) might
actually use it more often.
If you must have a department store telescope then enjoy it and have fun. There
are many 'serious' astronomers who started their hobby with one.
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