Telescope question (newbie)

A friend of mine was told by a shop assistant that in the cheap
low-power range of telescopes, refractors are as good as reflectors. The
asistant said that refractors can also be used to view earth-bound
scenery but reflectors can't. Is this true?

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dave conz wrote:

A friend of mine was told by a shop assistant that in the cheap
low-power range of telescopes, refractors are as good as reflectors. The
asistant said that refractors can also be used to view earth-bound
scenery but reflectors can't. Is this true?

I don't think so, but there are a few factors that make it more
awkward to use a reflector for terrestrial observing. Reflectors are
generally larger than refractors in the same price range, and are
therefore less likely to be suited to a small altazimuth mount like a
camera tripod: a Dobsonian mount's pivot-point is too low to the
ground for viewing at a low angle (also requiring that the observer
squat or crouch very low to look through it), and it's difficult to
'sweep' using an equatorial mount. A Newtonian telescope's focuser is
inconveniently positioned at the front end of the instrument instead
of the back, and they're also awkward to fit with an image inverter,
which is necessary to make the view appear the right way up
(irrelevant to celestial observing).

Note that "low-power" and "cheap" don't necessarily go together; in
fact a tell-tale sign that a 'scope is being marketed to beginners
who don't know any better is an unreasonably high magnification being
advertised on the box -- it'll indeed come with eyepieces that
nominally provide the stated power, but the small aperture or poor
quality of the instrument will make it nearly useless when configured
that way.

--
Odysseus

I have found that refractors are easier to use overall for a beginner. In
that regard, they are also easier to use for viewing terrestrial scenery.
The reflector's design makes it difficult for beginners to effectively
utilize.

Hope this helps....


"dave conz" wrote in message
...
A friend of mine was told by a shop assistant that in the cheap
low-power range of telescopes, refractors are as good as reflectors. The
asistant said that refractors can also be used to view earth-bound
scenery but reflectors can't. Is this true?

-------------------
http://www.mediacollege.com - Video & electronic media resources

Thanks for the replies - that clears it up.

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On Sat, 07 Feb 2004 23:05:17 +0000, Odysseus wrote:

dave conz wrote:


Note that "low-power" and "cheap" don't necessarily go together; in fact a
tell-tale sign that a 'scope is being marketed to beginners who don't know
any better is an unreasonably high magnification being advertised on the
box -- it'll indeed come with eyepieces that nominally provide the stated
power, but the small aperture or poor quality of the instrument will make
it nearly useless when configured that way.

For example, the 60mm CStar refractor I have (as a beginner that didn't
know any better) came with 4mm and 20mm eyepieces, 0.9" diameter. With the
20mm and no barlow it's 35x; the 4mm and barlow is 175x, and that is about
the limit for viewing. At that power you can see Saturn's rings clearly
and some blurred stripes on Jupiter but they are not large images. Mars at
opposition was just an orange blur, though, with no detail my eye
could see. Also can spot a bright nebula such as Orion (haven't been out
enough to locate others yet). Put on the barlow with the 4mm and it should
be, according to the box, 525x, but it's unusable for anything other than
watching blurs track past; not enough definition for reasonable viewing.

Chuck Sterling