rdu (07/02/82)
In the course of my unschooled browsing for a first telescope I have encountered a curiosity: two telescopes whose specifications seem roughly equivalent and yet whose prices are disparate. The two are the Celestron C90 and the Questar 3 1/2. According to their brochures they have the same design (Maksutov-Cassegrain), aperture (3.5 inches) and approximate resolution (1.0 arc seconds for the Questar vs. 1.3 for the C90). The C90 even achieves a higher "maximum useful" power (210x vs. 130x) and yet the Questar costs about four times as much. Why? I would be interested in others' knowledge or opinions on what makes a good amateur telescope, because apparently my original intuitions (light- gathering, resolution, power) are inadequate. How do different designs compare? (Here I would consider actual experience more telling than theory.) How important are special lens coatings? How real are qualitative considerations like sturdiness and workmanship? Sign me In the Dark in Indiana [ Mark Raabe (pur-ee!rdu) Purdue Library Systems ]
sbg (07/07/82)
I too recently started looking for my first telescope (also
pretty much of a neophyte) and three weeks ago bit the bullet. I
was interested in a telescope with a primary mirror of about 6 to 8
inches. I looked mainly at Questar and Celestron and was amazed at
the differences. Comparing the Questar 3 1/2 and the Celestron C-8,
(both numbers are measures of aperture in inches) the Celestron cost
less than 1/2 as much for more than twice the power!
Another thing which impressed me was the sales pitch. While
Questar told me all about how refined their manufacturing processes
were, Celestron told me what the most important aspect of any
telescope is -- aperture. This is certainly in line with what I
always believed. Celestron also gave a nice description of the
three types of telescopes - refractor, Newtonian reflector, and the
Cassegrain; and the five different types of Cassegrain telescopes.
I learned a lot from the Celestron brochure and would recommend it
just for the information it provides about amateur telescopes. To
obtain it, send $3 to
Celestron Internation
2835 Columbia St.
Torrance, CA 90503
One more note, I purchased my telescope from a Celestron Dealer
(Middlesex Photo) and got it for 65% of the price listings! I'm very
happy with it and the seeing has been great. Definitely much better
than I have seen with smaller telescopes. Last nights lunar eclipse
was phenomenal!
Steven B. Goldsmith
Bell Labs, Murray Hill