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TELESCOPES
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6
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HOME PAGE
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A CLOSER LOOK AT REFLECTORS
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INDEX
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NEWTONIAN REFLECTORS
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The greatest advantage to Newtonian reflectors is their cost per millimeter of aperture
(size). Another great advantage is the ability to put the
large ones
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onto a simple and inexpensive mount like the Dobsonian
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mounts.
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It is more important to place a refracting telescope onto a equatorial mount
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(dimensions).
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The long focal lengths
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because of their long focal lengths
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give the refractor a narrow field of view which needs more tracking assistance from the
mount than a reflector. The reflector generally comes in
shorter focal lengths which have
wide fields of view. So what I'm saying is the money you spend on a refractor with an equatorial
mount can be used to buy a
reflector on a Dobsonian mount which will give you a telescope
three
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TELESCOPE LINKS:
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Basics
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Mounts
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Light Gathering Power
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times the size for same money.
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This means awesome
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light gathering power.
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Closer Look At Refractors
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Dimensions
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A reflector's mirror is a lot simpler and cheaper to make (do one at home if
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Balancing
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you wish through
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BYOT - Build Your Own Telescope)
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than the specialised,
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Eyepieces
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highly accurate figuring of high quality glass to make an achromatic lens.
The mirror of a reflecting telescope is completely free from chromatic aberration, unlike
the refracting telescope. However the eyepieces used to
magnify the image are of the refracting
type so there could be some aberration if cheaper eyepieces are used.
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Cleaning
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Tips
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Astrophotography
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Build your own telescope
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Build your own telescope
for schools
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Binoculars
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A frequently asked question about reflectors is, can they be used during the day? The answer
is yes! Reflecting telescopes provide wide field , bright
and clear pictures during the day,
but the image is upside down and the other way around (back to front). This could quite
annoy some people, but the people
who use them during the day and myself discover we
look at the picture for what it is and not be bothered if it's backwards or upside down.
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Reflecting telescope mirrors which gather the light are just a parabola curved surface with
with a coating of aluminium placed on it. It's this
aluminium coating that does all the work
of gathering the light, whereas the shaped glass is only there to support it. Telescope mirrors
can be made out of anything
hard really, and have the aluminium coating put on them, but
glass is easy to grind and polish to a accurately flat surface. Also glass has fairly low
expansion
rate so it will not warp much when placed into a different temperature like taking the telescope
from inside a warm house to outside in the cold. Other
materials can be used for making
the reflective mirror, but are more expensive and harder to grind, especially at home. eg.
Pyrex or fused silica.
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HOME PAGE
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INDEX
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Contact Us - telescopes@adam.com.au
Australian
Residents Please Call (08) 8381 3188
International Residents Please Call 61+ 8 8381 3188
Australian Fax Orders (08) 8381 3588
International Fax Orders 61+ 8 8381 3588 |
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Chinese Equivalent Comparison:
