| A Guide to find
the right telescope and other neat stuff for beginning Amateur Astronomers.
Choosing the right telescope for you.
Starting a hobby
in astronomy does not need to be expensive. You do have to be
careful though to get the right telescope. A common misconception
is that you need a lot of magnification to see the wonders in
the heavens. You don't, but you do need light gathering power.
A lot of objects you want to see are faint and fuzzy, such as
nebulas and galaxies. Other objects such as star clusters are
just faint. Most all of these can be viewed at powers ranging
from about 30X to 150X but need telescopes that are at least 4
inches in diameter (the larger the better and more expensive).
To view the planets
and the moon magnification and sharpness is the most important
and a lot of light gathering power can actually get in the way (except for
the outer planets). The magnification you need will start at about
60X up to the limit of your telescope and/or atmosphere limits.
Here you can start with a 2 inch telescope and see the planets
and moon quite well.
So what kind of telescope should I get?
I want to see everything!
Ahh! good question.
And there is no one good answer, but for the beginner I recommend
getting a 6 inch to 10 inch Newtonian reflector with a solid stand / tripod.
A telescope of this type will serve you well in all areas of astronomy
and is one of the least expensive telescopes per inch /diameter of scope.
If you have an equatorial mount you can, at a later date, put a clock drive on it. It
will track the stars for you (a must if you want to photograph
what you see). If you are real short of money you can get a
(looks like a cannon on a lazy-Susan). They cost about 1/2
the price of an equal size Newtonian but work very well for easy steady viewing.
You can more or less forget about a clock drive and astrophotography. Here the compromise
is made with the telescope mount. It is one of the most stable, but does not
align with the earth's axis and therefore can't be made (it can, but it is costly and only works for short exposures) to track the motion of the stars across the skies.
With these telescopes
you get very good views of nebula and galaxies, You get good views
of the outer planets, and poor views of Jupiter and all inner planets
including the moon (they are all too bright creating too much glare). But there
is an inexpensive way to drastically improve your view of the
those bright objects using what is called an Off Axis
aperture Mask. This is basically a front telescope cover with an off center
hole in it. It cuts down on the light entering your telescope
and cuts down on all the edges light can refract on. This makes
the image of very bright objects a lot sharper and dimmer so your scope
can now see clearly the brighter planets and can even be used for terrestrial viewing.
If you get a
60mm (2in.) or larger refractor
These are excellent for the moon, planets, double stars, and brighter
star clusters. These telescopes give the sharpest image of all scopes.
Avoid the department store telescopes (including reflectors). Most department store telescopes
have very poor optics and very wobbly tripods. They
advertise high power such as 600X but the best a excellent quality 60mm telescope
can manage would be 125X anything higher would just be blur.
There is nothing more frustrating than pointing your telescope at
something and watching it disappear as soon as you move your hand to focus.
It is equally frustrating to have to wait for the vibrations to die down only
to have a small breeze to start them up again. If your main interest is to view to planets and the moon
and your budget is small, then this is the best type to get (but NOT THE DEPARTMENT STORE TELESCOPE).
If you can get a refractor telescope that is big enough to see nebulae and galaxies (4 inches and up) you are
wealthy indeed. Large refractors with good optics are the most expensive telescopes
per inch of objective (the front lens) you can buy.
The best overall telescope type you can get is the
Schmidt-Cassegrain type. They
give good overall performance, are the most compact and the easiest
to transport, and can be purchased with many features such as computerized
star tracking. Unfortunately they are expensive too.
For more information on this subject you can read:
Sky and Telescope Magazine'S
Tips on Telescopes
How to Choose a Quality Telescope for Under
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Go to telescope stuff you need.
Stuff for Beginning Amateur Astronomers.
W hat to get????
Here is a small shopping list.
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Star Charts and other star / planet finding
O ne of the most
basic and useful star finding aids is a Planisphere. These are
little charts where you turn the dial to match the date with the
time and it will show you what stars and constellations are up in your sky
and where. These sell for about $2.50 to 10.00 (a must get).
You can get an computer program that can give you up to date charts for your area.
The price for these can range from FREE to more than $500.00. The free one is
highly recommended it main draw back is you can't print the charts. Find it
at www.fourmilab.ch/. I use Earth Centered Universe
(ECU) by David Lane. It creates great charts, has a lot of features, and is
VERY reasonably priced. You can down load a shareware version at www.nova-astro.com.
The next thing you need is a good star map, book, or Atlas (kind
of like a book of city street maps but for stars). They will show you most of
the brighter stars that you see in your telescope. That will help
you find faint objects.
A subscription to Astronomy and/or Sky and Telescope Magazine is VERY useful (and interesting).
They will tell you where the planets are for that month, whats new, plus a whole
bunch more. (must get at least one of them.)
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Finder Scopes and Reflex finders.
N ow that you have
found the object on your star chart that you want to see and you
have used your Planisphere to locate what part of the sky it is
in...Now what? Simple (HA!). You point your telescope to that
area and sweep back and forth until you find it? NO !
you use a reflex finder to get you pointed very close to the area
your object is in. Then if you don't have a Finder Scope you put
your low power eyepiece in and sweep slowly until you find it.
Not as hard. But if you do have a finder scope, you sweep the
area matching star groups with those on your star charts. When
you find the star group or object, you center it. The object should
now be in your telescope under low power(if you have aligned your
finder with your telescope).
I recommend that you get both a reflex finder and a finder
scope. If you are on a tight budget get the Reflex type finder.
When you get (or upgrade) a finder scope get one at least 30mm
in diameter. Get a bigger one if you have a telescope larger than
60MM and can afford it.
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Filters for your telescope.
F ilters come in
all types for all kinds of purposes. There are colored filters
to enhance planetary detail. There are filters to allow you to
safely view the Sun. There are filters to remove excess light
to view the moon. There are filters to fight light pollution.
None of them are absolutely necessary EXCEPT the solar filter
if you want to explore the Sun. Never get the type of solar filter that attachs
to the eyepiece. If you have one that came with your scope - throw it away.
These filters are very close to where the main lens(mirror) focuses (focal point)
and the intense heat can cause the filter to break while viewing. This will FRY
your eye before you can pull it away. I had this happen to me, fortunealty
I was not looking through the eyepiece then. I recommend getting the filters
that will fit your viewing habits and solve your problems.
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Your telescope probably
came with at least one eyepiece maybe more. You need to save up
so you have at least three eyepieces of Very Good Quality. The
three you need will be: one for low power, one for medium power,
and one for high power. If you get poor quality eyepieces you
will see dim poor quality views. Its is better to get one very
good quality eyepiece than to have a bunch of low quality ones.
The powers to get first is 20x to 30x, then one that's about half
way between that and your scope highest useful power, and one
that is high power (40X - 60x per inch of telescope main lens
or mirror diameter (objective) up to about 300x max.)
Want to how to figure out what power your eyepiece will give
First find out what your telescopes focal length(fl) (Focal length
of Main Objective) is. This is usually given in Millimeters(mm).
Then divide that by the focal length of your eyepiece also given
in mm. For example suppose you have a 60mm (2in.) refractor telescope.
you look in the documentation (on the side of some telescopes)
and find that your focal length(fl) is 900mm. You look on the
side of (or on top of) your eyepiece and find you have a 9mm eyepiece.
Now you take 900mm divided by 9mm and get 100x(900/9=100). Your
telescope is a 2 inch (60mm) telescope and you can get 50x - 60x
per inch. That would be your high power eyepiece (the highest
you could go with that telescope would be a 7.5mm - 7mm eyepiece).
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