ETX TECHNICAL TIPS Last updated: 23 March 2000

Some Add-ons

I new into astronomy and seem not to have quite the size of budgets my US colleagues have, so I have made a start on some home grown ideas.

First a Kwik Focus Ring. Take some plastic coated cardboard and cut out a 10cm diameter disc. Then at a radius of about 3cm and 120 degrees apart cut three holes 2.6cm in diameter in your disc. Seal the edges of the cuts with PVA glue or similar to keep the wet out on those damp winter nights. Hey presto, your own focus disk for allot less than $30 or my English equivalent. So next time it's all clouded up outside and there's nothing on TV, break out the old school compass, fit a blade in it and off you go. If you've got the proper beam cutting compass all the better. By the way it also acts as a good light reduction filter for those crystal clear nights when the moon just seems too bright.

Next, the Autostar drive training procedure seems a little Heath Robinson to me! The phrase 'center the target in the eyepiece' seems open to allot of potential error to me. By playing around with the standard 26mm eyepiece I found that an object placed into the bottom of the eyepiece comes into focus at just about the same depth as a step on the black lens assembly retaining tube inside the chromed outer. So out with my trusty beam compass and cut a 26mm diameter disc of clear flexible plastic (Overhead Projector Stuff should be good enough). I then cut out on a radius from the outside edge a 4mm deep 2mm wide slot (more on this later, but DO remember to cut it out). Now flex the disc an pop it past the step in the inner tube in the eyepiece, turn the eyepiece over and tap it to settle it on the step. Put the eyepiece into the telescope, you will now find that the hole where the compass needle was is now in the middle of your field of view like a dot sight. Use the hole to sight your target and follow the drive training procedure. When you've finished, remove the eyepiece, turn it upside down gently and then with a paper clip or similar object hook out the disc using the slot you cut in it earlier (you did cut one didn't you!). Be very careful not to touch the lenses as your trying to hook it out. When you've got it out put it somewhere safe for the next time you upload the latest software, or the like.

PLEASE NOTE THAT THE ABOVE SUGGESTIONS ARE FOR HOME USE ONLY AND MAY INFRINGE COPYRIGHT OF DESIGN OR PATENT'S IF YOU DECIDE TO START GOING INTO A PROFIT MAKING ENTERPRISE WITH THEM. I CAN IN NO WAY BE HELD RESPONSIBLE FOR DAMAGE TO YOUR EYEPIECE OR DROPPING FOREIGN OBJECTS INTO YOU ETX OPTICS, OR EVEN BEING RACKED OVER THE COALS ABOUT TAKING SHEETS OF OHP FILM FROM WORK!. BUT THESE IDEAS HAVE WORKED FOR ME, I'M JUST 'SHARING'.

ETX users may be interested to know that the lid of a 350g tub of Smash instant potato is an exact fit on the end of the tube.(a tiny inner rim needs to be trimmed with a craft knife). With three holes punched through it makes an excellent focus aid or a temporary cover for the objective lens.

Steve Grosvenor
Dudley
West Midlands

by:IDO

I got some e-mails that asked me how I make the focus... so, I send to you my way to the "perfect focus" its really works!

I hope you put it in on your site becuse it could help so many peoples that just have trabels to get an object into focus or cant get prime focus photos becuse the focus problem.

instructions:
first of all-you should cut the hols (they are pinted in gray) . then- put the page infrunt of the telescope miror (as shown), great job! now, all you have to do is to look throw your eye/camera and to focus antil you will see one objet - good lack!

IDO
(thanks you mike!)

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