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Refractor Telescopes

by bombshop
Tags: refractor, telescopes
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Nov7-03, 06:32 AM
P: 3
Hello there everyone...
Lately i've been working on the idea to build my own telescope...
now as the reflector telescopes are kinda hard to build (especially their mirrors ! ) i've decided to build a refractor telescope...
What i am asking is :
Do you have documents and web site adresses or people that can guide me through the rest of the installation progress..? :)
I can even use some documents about building a binocular...
So any docs and adresses about 'refractors' are welcome...
Catcha later
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Nov7-03, 09:04 AM
Sci Advisor
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chroot's Avatar
P: 10,427
Are you purchasing the lens, or making it yourself?

Refractors are actually much more difficult to build than reflectors, because

a) lenses are more difficult to grind than mirrors and

b) a single-lens refractor will have horrible chromatic abberation and won't even come close to being as good as a cheap store-bought refractor.

- Warren
Nov7-03, 05:21 PM
P: 3
Hmm i didnot think about it.
I planned using an eyeglass lens as newton did :)
also i couldnot make a decision about building a reflector or refractor...
as i said before mirrors are hard to build. But Schiefspieglers has a very attractive design. But i cannot find info on building anything but dobsonians...
waiting for experts to enlighten me !...
I am pretty sure that at the end i will start building a Schiefspiegler but a spyglass would do fine for the very first beginning... :)
anyways Thanks for any kind of help


Nov10-03, 10:02 AM
P: n/a
Refractor Telescopes

I recently finished building a 12.5" f/5 Newtonian Reflector on a Truss Tube Dobsonian mount. Here is a link to a pic along with a link to a great forum for telescope construction as well as other astronomy stuff.

Nov13-03, 09:19 AM
P: 1,591
What is your main interest in Astronomical viewing? What do you want to see? This should be your starting point.

I have built three telescopes and have ordered parts for a fourth one. Each one has its strong points and its weak points.

My best planetary and lunar scope is a 4.5" f8 reflector.

I built a 6" f5 reflector that works fairly well for star patterns, galaxies, and nebulas.

I built a 2.5" f4 copyscope that uses a copier lens that I bought through Surplus Shed for $6.00 for the objective lens. This is good for terrestrial viewing, star patterns and because it is only about a foot long, it travels well.

You can buy up to an 80mm Objective lens through Surplus outlets like They also can sell you the star diagonal and a rack and pinion focuser (unless you want to make your own. )

An 80 mm 900fl f11.25 Objective doublet will make a decent planetary scope.

An 80 mm 400 fl f5 will make a decent rich field travel scope.

If you are just worried about making your mirror, here is the web address for Orion Telescope. They sell decent mirrors fairly cheap. The main reason people make mirrors used to be that they couldn't get good mirrors for a low enough price. The commercially available mirrors especially the ones 1/8 wave or better, 4.5" - 8", and f6 to f8 or longer are probably fine.
Nov16-03, 12:46 PM
P: 1,591
I just finished a 80mm 900mm FL refractor that I assembled from surplus parts. It works great. I used a couple of black foam core ABS pipes 2' long 3" and 4" long 2" and a 3"x 2" reducer to create the tube.

The whole project cost me about $60.00 (I already had the eyepieces and I'm currently using the tripod and mount from my nexstar 80.) Next part is to build it an equatorial mount.
Nov21-03, 03:16 PM
P: 3
hmm.. this not really helping... i need some information on how to build it.. and also i may use some eyeglass lens for it so i need the schematics and also the formulas for a refractor telescope. not a reflector because the mirror is hard to make.. :)
So have a good day.
Nov21-03, 03:57 PM
P: 1,591
Eyeglass lenses probably won't make a very good telescope. The problem is they have too short of a focal length and such a small aperature.

Have you considered trying to find an old pair of binoculars and canibalizing them for the eyepieces and the objective lenses?

Here is a sight on optics:

and here is a good article on building a cheap refractor similar to that used by Galileo.
Nov21-03, 04:00 PM
Sci Advisor
Labguy's Avatar
P: 734
Originally posted by bombshop
hmm.. this not really helping... i need some information on how to build it.. and also i may use some eyeglass lens for it so i need the schematics and also the formulas for a refractor telescope. not a reflector because the mirror is hard to make.. :)
So have a good day.
Sorry, but trying to make a telescope with eyeglass lenses or anything other than a basic ready-made objective lens is a futile waste of time, unless this is just an experiment in bad optics. The scope you make will most likely show nothing useable at all. Much easier to buy even a surplus binocular lens (some people give them away for free) and a cheap eyepiece or two. Any math or schematics we could find would be above and beyond your originally stated goal. Special tools would be needed.


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