Answers to some commonly asked
questions
Q: Which type of telescope should I
get: a refractor, reflector, or Catadioptic?
|
| A: Each has its own advantages and
disadvantages, which you must weigh against your own interests and needs.
Refractors
are fairly portable and offer the finest image quality, but they're also the priciest per
inch of aperture. They excel for detailed views of the Moon and planets, but aren't
very well suited for deep-sky observation. Reflectors (Newtonians) boast
generous light-gathering power for an economical price. They provide excellent
performance on deep-sky clusters, nebulas, and galaxies. Reflectors tend to be
bulky, and require more maintenance than other telescopes. Catadioptic
telescopes,
such as the Cassegrains, are compact and portable, even in apertures of 8" or more.
They offer good, all-around optical prowess and are easily adapted for
astrophotography. They're not cheap, though; costs run upwards of $4500.00 for a
12" SCT. |
|
Q: What will I be able to see?
|
| A: The larger the telescope's aperture, the
more you'll be able to see. But even a 60mm refractor will reveal many breathtaking
sights, including the rings of Saturn,
Jupiter and its four largest
moons, countless rills
and craters on the Moon, the ghostly Orion Nebula, and the dazzling Double Cluster, to
name a few. With bigger telescopes, you'll see fainter objects and finer details.
But even with a telescope as large as 200" you'll see very little
color. Human eyesight is not capable of perceiving color at so faint a
luminosity. You won't see images like those viewed in all the popular
astronomy books with lots of color and detail, because these are time-lapsed
photo's. |
|
Q: What type of telescope mount is
best?
|
| A: That depends. An altazimuth
mount is
simpler to operate than an equatorial mount, and lighter in weight. Altazimuths
generally can't be motorized, however, and they require movement in two directions
simultaneously to track celestial objects. An equatorial mount is a bit more
complex, but offers the advantage that objects can be tracked manually by turning only one
knob. Better equatorial mounts can be equipped with a motor drive for automatic
tracking. An equatorial takes more time to set up, and must be polar-aligned. |
|
Q: How does sky darkness factor in?
|
| A: The darker the sky, the better. But
even from a moderately light-polluted site, you'll be able to enjoy nice views of the
Moon, the planets, and possibly some of the brighter deep-sky clusters and nebulas.
When skyglow (or light-pollution)
is a factor, choose a telescope of smaller aperture (4" or less) and high
focal ratio (f/8 or higher). Using a light-pollution filter helps. If
you'll be observing from a dark, rural site, a telescope of any aperture and focal ratio
will provide grand views. |
|
Q: Isn't high power really important?
|
| A: Surprisingly, no. Aperture (the
diameter of the main mirror or lens), not power, is what determines how much you'll
be able to see. Keep in mind that the higher the magnifying power, the dimmer an
object will appear. So high power is best reserved for studying bright objects, such
as the Moon and planets. In general, the sharpest, most pleasing views are obtained
at low powers of 25X to 50X. |
|
Q: What does a motor drive do?
|
| A: A motor drive (or "clock
drive") is like cruise control for a telescope. It enables the scope to
"track" the motion of the stars as they appear to move from east to west due to
the Earth's rotation. Essential if you want to do astroimaging!
updated:
|
|