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shelley
member
Reged: 03/08/09
Posts: 54
Loc: Massachusetts, USA
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Well, last night I had my first chance to try the scope (Meade ETX 125EC). I had a great view of Saturn with the 9mm EP. It was extremely hard to track it manually as I am used to it with my Dobs. I connected the electronic controller and it was a breeze!.
One thing I noticed when focusing is , if I am going clockwise it focus fine but if I go over slightly the focusing point backing up the knob counter clock wise does not bring it back into focus I have to make a whole turn and then go at it again from the clock wise direction. Is there something I can do to adjust this? or is it the nature of the Mak design? I guess I am used to the 2 speed Crayford style focuser on my Dobs which if I go over slightly I can bring it back into focus by going in the reverse direction.
I hope this can be rectified by some type of adjustment.
any suggestions will be greatly appreciated..!
Thanks...!
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Zhumell Z10 deluxe Dobsonian-
Meade ETX-125EC Maksutov Cassegrain-
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brianb11213
Carpal Tunnel
Reged: 02/25/09
Posts: 2085
Loc: 55.215N 6.554W
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Quote:
if I go over slightly the focusing point backing up the knob counter clock wise does not bring it back into focus I have to make a whole turn and then go at it again from the clock wise direction. Is there something I can do to adjust this? or is it the nature of the Mak design?
It's not correct. Try working the thing over its whole range - in and out - a few times, just in case the grease has congealed, this will even it out.
There is usually a bit of backlash in the focus knob but nowhere near a whole turn!!!
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John Carruthers
Skiprat
Reged: 02/02/07
Posts: 2269
Loc: Kent, UK
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Sounds like a little play where the focus screw runs in the mirror carrier. A stronger spring would help or a shim to take up the slack, a nylon or teflon washer would be good. (ignore the "bezel popped out" bit, that was another scope)
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Jc
ATM 10" F6.1, 1/25th wave spec (max wavefront error +/- 1/12.6 in zone 4 of 6, sodium light )
6" F7 spec
127mm F9.4 Refractor
10 x 50 bin
ETX80 (finder)
Canon 20D
PST
DSI 1
and a curious mind
Edited by John Carruthers (05/22/09 07:34 AM)
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JT5
professor emeritus
Reged: 11/08/07
Posts: 576
Loc: Ozarks of Missouri
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Shelly. Check for an Astronomy club in your area. If you contact them you should be able to get some hands on help from a member. The Meade ETX scopes are fairly common. I would hesitate in suggesting a "newbie" try to dig in and fix the problem.
John
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My wife shares my love of the night skies and tolerates all of my other hobbies.
Televue Pronto w/Starbeam pointer and Televue tripod
Meade 2045D, ETX-125PE, 12" Lightbridge
Celestron: 7Amp PowerTank, 15X70mm binoculars
Meade, Swan and Televue Lenses (33, 26, 20, 15 & 9mm), Televue Barlow
Catsperch Observing Chair
Member: Astronomical Society of Eastern Missouri
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jgraham
Postmaster
Reged: 12/02/04
Posts: 6751
Loc: Dayton, Ohio
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I don't know if it's 'nomral' or not, but I've long had the habit of always setting the focus in one direction; if I over-shoot I'll turn back and try again. I don't think I've ever seen a stock focusser on any scope that I could afford that didn't have some backlash. I even use the stock focussers on my imaging scopes with the same procedure.
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-John
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Homebuilt scopes from 4.25-16.5"
Meade LXD75-N6/SN6/SC8, DSX-90, ETX-60BB, ETX-125PE, DS-2130
Orion StarBlast, BinoViewers, Coronado PST
Rebel XT/XTi, DSI Pro (I, II, & III), DSI, LPI, Electronic Eyepiece, Phillips SPC900NC
Tasco 60mm Refractors
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