This page last modified 2002 December 21

Upgrading a 60mm Refractor

The department-store incarnations of this telescope often leave a lot to be desired, but can usually be easily upgraded with the application of a little time.

The advice on this page is greatly expanded upon, with more pictures, in my book Astronomy with Small Telescopes


Eyepieces

Of the supplied eyepieces, generally the only one worth keeping is the weakest one, i.e. the one with the greatest number, usually 20mm or 25mm, on it. It is worth getting a decent quality high(ish)-power eyepiece such as a 9mm Orthoscopic. An alternative source of eyepieces is broken binoculars — the eyepieces are usually Kellners, but are sometimes Erfles on wide-field binoculars (identifiable by the unusually large eye lens).

If you have 24.5mm (0.965") eyepieces, you may wish to see if you can use standard (31.7mm - 1.25") eyepieces with a hybrid diagonal — the eyepieces will be usable if you upgrade later. You will not, however, be able to take advantage of the wider field of low power 1.25" eyepieces, because the 0.965" bit of the hybrid diagonal will cause vignetting. Also see below.


Barlow lens

eyepiece made from Barlow tube

The supplied Barlow is usually of poor quality, but the tubing can be cut down to house eyepieces made from broken binoculars.


Sun Filter

If the telescope is suppled with an eyepiece-fitting Sun Filter, destroy it — they are dangerous and can break in use.


The Finder

Finder diaphragm

If you have one of the 24mm finders, the simplest way to improve this is to remove the optics and use the remaining tube as a sighting tube. alternatively, remove the diaphragm that is just behind the objective lens. The resulting finder image will be much more colourful, but also much brighter. Another alternative is to push the diaphragm down the tube so that it acts as a field stop — you will need to work out where this should be or, if you don't know how to, justdo it by "trial and improvement".

Finder made from binocular

If you want to replace the finder, either make one (junked binoculars again), or get one good enough to use on the telescope you're saving up for.


Other options are to make simple "vee and blade" gunsight arrangements, sighting tubes, or to make a simple unit-power finder .


Focuser

Some people suggest replacing the focuser with a 1.25" one, but this is not usually either simple or cost-effective. An alternative is to try a "hybrid" star diagonal, which will accept 1.25" eyepieces, but check that 1/25" eyepieces are able to be focused (sometimes they can, sometimes they can't).

If you are upgrading a little reflector, a 1.25" focuser is a viable option.



Mount

Water container stabilisation

Ensure that all the bolts are kept tight. You can improve the stability by suspending a weight (e.g a full water container) from the mount.

Tripod

Reinforced tripod
Either make yourself another tripod (and another altazimuth mount whilst you're at it), or cut some truncated triangles of thin plywood to fit between the upper parts of the tripod legs and pin or tack them to the legs, so that the result is like a triangular pyramid. The tripod no longer folds for storage, but is much more stable.

Add a Chain

Add a chain...

A two-foot length of heavy curb chain, taped to "big end" of the telescope, will damp vibrations. .

What to do with it once you've replaced it

It can become your first guidescope once you have started doing guided astrophotography, or could store unobtrusively in a car so that you always have a telescope to hand should you need one.