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Meade Focuser - It Rocks - Maybe ?


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#1 Randy Rourke

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Posted 14 February 2008 - 02:36 PM

I have only had my 80mm EDT for about six weeks and yet to get clear enough skies/chance to do a proper evaluation/star test yet did notice having used it at lower powers and bad weather some things that intially concerned me about the focuser, yes it is not a feather touch, but then again at 699.00 for a fast triplet, I think the scope is a major value. Hard to put a 400.00 fouser on a 699.00 scope.

My main concern with the factorty focuser was that the tension adjustment knob was/might be less than effective compared to some other brands, This of course is evil, becuse we can't be sitting around experiencing focuser envy, it will drive you mad <g>!!!!

In any event I came accross a nice website involing a GSO brand focuser and how to tune it up.
I thought hey I'm up for this, and here is were the magic bagan...1) Wax the draw tube.....it's a good thing.
2) A GSO is not the same focuser as on the Meade, it's also a good thing...3) The Meade can Rock..if we take the time to realise it's advantage, so here goes.

1) The problem with getting "an ultra adjustable" tension setting is attributable to three issues, a) the threads on the tension screw are not that finely pitched or long, hence any adjustments in a system that by all accounts needs to be EXTREMELY precise are hard to achieve. (See how Willams achieves this in their older SCT crayfords).  :) There are two bolts that hold the lower focuser shaft busing/race in place, if these are too tight it makes it hader to overcome the effects of scenario A.  c) The factory/user upper bearing race alignment also factors into the equation, and this is the BEAUTY of the MEADE focuser......

If we look closely at the way in which the upper bearing race is attached within the focuser body, we see an arraignment that is different than the GSO or the Williams, there are a total of SIX bolts/screws that work n a push/pull configuration, the inside panhead bolt on each side is the "pull", while the outer hex (scrub) srews are the push.

This is where the "IT ROCKS" part comes in.  It is not too hard to learn how to tweak the alignment of the upper bearing/race assembly. I found that VERY smal adjustments work like a charm, make sure to use a HIGH quality hex wrench or you might strip the hex sockets of the bolts/screws. It does not require much torque to hold the bearing/race assembly properly.  If you feel a need to tighten the center (pull) bolt, just tweak/loosen  each of the outer srews on a tade (1/8 to 1/16 of a turn).  While doing all of this, keep your wits regarding TWO things, 1) The draw tube needs to remain centered with respect to the focuser body. 2) The eyepiece/diagonal holder should sit flush with the focuser body. If #1 is a problem, then adjust from one side to another (ie loosen the outer screws/tighten the inner bolt, on the "wide gap" side, then losen the inner bolt and tighten the outer screws on the "tight" side) If #2 is a problem, then adjust only on the side where the eyepiece/diagonal holder is not sitting fkush. (ie loosen the front srew, tighen the rear screw, or vice versa)

If I had a camera, I would post pics, becasue I know they are worth a thousand words, and I hope I have conveted all of this in an understandable fashion.

In all honesty, I feel that the abilty to fine tweak the upper beaing race in the focuser body is nothing short of genius. Yes it takes some time to get use to the process, but in the end you can tweak the response of the focuser to EXACTLY the type of feel you desire. Fine tunig the entire upper race assembly is much better than relying on a quasi fulcrum means. You can get both better "holding" power for heavy EP's, Camera,.. etc without needing to adjust the normal tension screw "too tight". From the factory, I flet that the focuser was "loose" on my 80mm EDT (Of course my Williams SCT did not work at all!!), yat after learing how to tweak the thing, it is SWEET  !!! No feather toch need , (if it only had dual speed, I'd be in heaven)

Regards
Randy

Lastly, if you a going to try this out, remeber 1) Work in very fine steps. 2) Wax your draw tube, it does help, and looks good too. 3) Remove the upper race assembly and check that the bolt holding them in are snnug (not to tight).

All in all,

#2 peter_4059

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Posted 30 May 2008 - 04:55 AM

Randy,

Great thread - now you've got me thinking - it would be great if you could post some pictures.

As for the dual speed you can retrofit a 10:1 mechanism.  They are available in Aus for about $40.

Cheers,

Peter.




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