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cosmoskid
professor emeritus
Reged: 11/15/08
Posts: 684
Loc: Indiana USA
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Why does the image shift when racking the focuser in and out? It has the electronic focuser hooked up to it.
Thanks for your help.
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"Educate and inform the whole mass of the people... They are the only sure reliance for the preservation of our liberty." Thomas Jefferson.
"Who are they to judge the life I live? Before you start pointing fingers, make sure your hands are clean.”
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Arthur Dent
Galactic Hitch-Hiker
Reged: 10/23/08
Posts: 1182
Loc: South Yorkshire, UK
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It is an inherent design flaw and a lot of Maks and SCTs suffer from image shift.
Just the nature of the beast I'm afraid.
Art
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If I like it, the wife says that we can't afford it!
=======================================================
Meade ETX105 (a nice "Grab & Go" scope) & Celestron NexStar 6SE with Bob's Knobs.
Various EP's from 6mm to 26mm, Baader Hyperion 8-24mm Zoom, a 2x Barlow, 2" diagonal and 7Ah PowerTank.
MRF and Antares 8x50 RACI finder scope - both for the 6SE's OTA, whilst the ETX gets a plain RDF.
Canon EOS 400D DSLR (un-modded) and SPC900 webcam. Finally climbing the AP Learning Curve!
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AlexDJ30
sage
Reged: 09/02/08
Posts: 276
Loc: Monterrey, Mexico
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Yes thats something inherent in the desing..but i know that on the etx are much more prominent, i have a C6.and the image shift is very little..instead my etx/125 have lots of it..why?? i dont know..i supouse its because they rush things when arming the etx scopes...
I like my etx..but the image shift its a pain to my eyes...after seeing my C6 have little..i amd now in the process of selling my etx-125..
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Equipment:
- ETX 125 AT
- C6 ASGT
- WO 66mm SD
- 2.5X ED Barlow, 8-24mm Zoom Eyepice
- Canon EOS Rebel XSi
- Celestron Nextimagen
- Orion Starshoot CCD cam
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Mike Cook
member
Reged: 07/13/08
Posts: 75
Loc: Moncton NB (Cloud Central)
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I've found that with my 125PE, that if I turn the focus knob back and forth a few times from full in to full out, it clears up much the image shift. I think the sticky goose grease or whatever they put in there loosens up. I do it after the scope has been sitting around idle a long time.
-Mike
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Meade ETX125PE Maksutov
Meade series 5000 80mm triplet on AT Voyager alt-az
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cosmoskid
professor emeritus
Reged: 11/15/08
Posts: 684
Loc: Indiana USA
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Here's a solution I came up with to my problem. It was the focus rod that was wobbling badly in it's threaded cell. I needed something that could hold it stationary while focusing. I bought a nylon nut and bored it out just enough to where the threaded focus rod would grab and cut its own threads but still turn easy. I ran the nut down flush with the surface and applied Gorilla glue around the outside of the nut and allowed 24hrs to dry. Not sure how long the glue will hold up. Time will tell. Just make sure the threaded focus rod isnt to tight threading into the nylon. I had to bore and fit bore and fit until it had little friction but not to tight. I also upgraded to a heavier spring in the process. This requires removing the three screws from the back of the scope and removing the OTA by itself. Then unscrewing the primary mirror cell from the back of the OTA. If you don't feel comfortable doing this, it's best you dont. You have to be very careful not to touch the primary when doing this. Trying this will most likely void any warantee with Meade. I take no responsibility for anyones decision on trying this. My results, No image shift and a nice smooth focuser. Just thought I would pass this on.
Thanks.
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"Educate and inform the whole mass of the people... They are the only sure reliance for the preservation of our liberty." Thomas Jefferson.
"Who are they to judge the life I live? Before you start pointing fingers, make sure your hands are clean.”
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Arthur Dent
Galactic Hitch-Hiker
Reged: 10/23/08
Posts: 1182
Loc: South Yorkshire, UK
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Wow Cosmos,
You are very brave to take your ETX to bits like that. 
Thanks for posting the details and picture.
Art
--------------------
If I like it, the wife says that we can't afford it!
=======================================================
Meade ETX105 (a nice "Grab & Go" scope) & Celestron NexStar 6SE with Bob's Knobs.
Various EP's from 6mm to 26mm, Baader Hyperion 8-24mm Zoom, a 2x Barlow, 2" diagonal and 7Ah PowerTank.
MRF and Antares 8x50 RACI finder scope - both for the 6SE's OTA, whilst the ETX gets a plain RDF.
Canon EOS 400D DSLR (un-modded) and SPC900 webcam. Finally climbing the AP Learning Curve!
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cosmoskid
professor emeritus
Reged: 11/15/08
Posts: 684
Loc: Indiana USA
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It isn't actually mine but I did get permission to investigate the problem. With the help of Mikes ETX site on disassembly I got the job done. I would imagine most of the scope is put together the same way it can be taken apart. It probably saved tons of money and with excellent results. The focuser is smoother, tighter and without image shift. The scope should have had something like this to hold the rod stationary in the first place. If anyone uses this fix you'll see why I replaced the soft spring.
--------------------
"Educate and inform the whole mass of the people... They are the only sure reliance for the preservation of our liberty." Thomas Jefferson.
"Who are they to judge the life I live? Before you start pointing fingers, make sure your hands are clean.”
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