nighty
sage
Reged: 12/31/06
Posts: 344
Loc: 75w39n
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I was checking my other mak with a chesire tool and decided to check The ETX 125. With the chesire in the ep holder, the alignment is off. No fiddling of the chesire in the holder could correct the misalignment. I unscrewed the port cap and held the chesire against the scope (crude at best)and the alignment is ok. The optics seem concentric but the ep holder the flip mirror and the optics are not aligned. 
Are there any fixes for this condition? 
I am going to check the weasner site and the etx site.
Thanks
Terry
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Rainbow
professor emeritus
Reged: 08/27/04
Posts: 662
Loc: Norfolk, UK
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Does the mirror 'click in' position nicely?
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Meade ETX 90 UHTC, 497 Autostar, 884 tripod, right angle finder.
CALIBRATE MOTORS and TRAIN DRIVES!
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Scott Horstman
Vendor- Backyard Observatories
Reged: 03/11/04
Posts: 8074
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I was just checking my back packer 60. Same thing. I hope there is a way to align the mirrors. It's off quite a bit.
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nighty
sage
Reged: 12/31/06
Posts: 344
Loc: 75w39n
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I Looked through the weasner site and found several references to loose or misaligned mirrors but not a post about how to fix the misalignment.
I checked several times and the misalignment was the same and not in the direction of the mirror's movement. Mine is out to the right looking from behind the scope.
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Scott Horstman
Vendor- Backyard Observatories
Reged: 03/11/04
Posts: 8074
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Mine too. I'm guessing the rear port can't possibly be collimated then. The top port seems to yeild a much clearer image.
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nytecam
Postmaster
Reged: 08/20/05
Posts: 5748
Loc: London UK
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Quote:
Mine too. I'm guessing the rear port can't possibly be collimated then. The top port seems to yeild a much clearer image.
Do you mean the other way around Scott the straight-through [non-flip mirror] view should be best 
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Scott Horstman
Vendor- Backyard Observatories
Reged: 03/11/04
Posts: 8074
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No cause the rear seems Barlowed or something too. I got a 25mm in both orfices and the rear is like twice the mag???
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John Carruthers
Skiprat
Reged: 02/02/07
Posts: 2270
Loc: Kent, UK
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I found the diagonal mirror was fouling the Barlow slide when it was flipped in/out. I ground a mm or so off the top edge and re-set it with silicone adhesive. This leaves enough 'spring' to pack the mirror in/out as necessary in order to get it square.
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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
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ETX80 (finder)
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Rainbow
professor emeritus
Reged: 08/27/04
Posts: 662
Loc: Norfolk, UK
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Quote:
No cause the rear seems Barlowed or something too. I got a 25mm in both orfices and the rear is like twice the mag???
The rear port is not designed for eyepices, but for cameras and such.
To reach focus using the rear port with an eyepice you need some kind of extension tube.
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Meade ETX 90 UHTC, 497 Autostar, 884 tripod, right angle finder.
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Scott Horstman
Vendor- Backyard Observatories
Reged: 03/11/04
Posts: 8074
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Quote:
The rear port is not designed for eyepices
Then why the 45 degree image correcting diagonal? That makes no sense to me. It's for birding I thought.
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Joe Lalumia
Post Laureate
Reged: 01/24/07
Posts: 3606
Loc: Rockwall, Texas, USA
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Directly from the Meade manual:
"Flip-Mirror Control (16, Fig. 1): The ETX-90EC includes an internal optically-flat mirror. With the flip-mirror control in the "up" position, as shown in Fig. 1, light is diverted at a 90° angle to the eyepiece. Alternately, with the flip-mirror control in the "down" position, light proceeds straight through the telescope and out the photo port (17, Fig. 1) for telephoto or astronomical photography using the optional #64 T-Adapter, or for observing with the optional #932 45° Erecting Prism (see OPTIONAL ACCESSORIES)."
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Rainbow
professor emeritus
Reged: 08/27/04
Posts: 662
Loc: Norfolk, UK
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Quote:
Quote:
The rear port is not designed for eyepices
Then why the 45 degree image correcting diagonal? That makes no sense to me. It's for birding I thought.
It will work with the 45 degree diagonal because that it increasing the light path length enough to reach focus.
What I meant was; if you put the eyepeice straight in the rear port it won't reach focus - which is why I mentioned the extension tube.
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Meade ETX 90 UHTC, 497 Autostar, 884 tripod, right angle finder.
CALIBRATE MOTORS and TRAIN DRIVES!
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nighty
sage
Reged: 12/31/06
Posts: 344
Loc: 75w39n
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Thanks for all the great suggestions on how to realign the flip mirror.
can't you guys get along?
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John Carruthers
Skiprat
Reged: 02/02/07
Posts: 2270
Loc: Kent, UK
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All I did was set a laser collimator in the 'top' (eyepiece) port and shoot it via the mirror to a paper target on the front of the objective. It took several tries to get it centred, stripping the rear assembly off each time and wedging the mirror to and fro. You may be lucky and get enough access from the rear port.
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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
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10 x 50 bin
ETX80 (finder)
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Veridian
sage
Reged: 07/17/06
Posts: 478
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I too bought one of the ETX-60 AT-BB models on Sunday- last one on the shelf.
It was clear the night before last and tried it out. Wooohaaa,,, comet tails as I've not seen in a while!!
Afterwards, I put the 'Cheshire' in the eyepiece port and the two reflected discs were separated far enough to put another disc between.
Went to different Wal-Mart last night to find another one, thinking the first was defective. As it was clouded over again last night, I put in the 'Cheshire' for a quick check and it too was out a good bit, but not as far as the first one. While continuing to peer into the Cheshire, I flipped the mirror back and forth a while and found that the reflected discs shifted to and fro from each other. "Must be this mirror", I thought.
Gave Meade a call today to try and explain the problem. Talked to two different people (neither were familiar with a Cheshire Eyepiece) and was advised to return the first one to Wal-Mart as a defect. As the second one has not been out under the stars I'll hold off returning it until it gets its fair chance on a star.
Now, I see in here that there may well be a user fix. Will this void the warranty if it is opened up to adjust the flip mirror? Modifying by grinding most certainly will one would suppose.
What are the chances that two in a row would be defective? Just my luck? Just my eyes, or am I doing something really stupid here?
[I have a collection of regular refractors, but this is my first experience with an ETX model.]
Thanks for reading this,
Mark J.D.
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John Carruthers
Skiprat
Reged: 02/02/07
Posts: 2270
Loc: Kent, UK
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I found the "front end droop" to be the main collimation culprit, and fixing that would certainly void any warranty  Try lifting the front up/down while peering through your Cheshire....
Several of these scopes have passed through my hands lately and loose mirrors are not uncommon. If you try to adjust yours be sure it's secure.
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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
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Veridian
sage
Reged: 07/17/06
Posts: 478
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Hi John,
Thank you for your reply and suggestions.
I guess I do not quite understand what "front end droop" is. Could you elaborate on this a bit?
Thanks,
Mark J.D.
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nighty
sage
Reged: 12/31/06
Posts: 344
Loc: 75w39n
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Hi John I tried to take an image of the mirror. The crosshairs are closer to the focus knob, so the alignment seems to along the pivot axis not perpendicular to it. I was able to move the mirror through the port by only fore to aft.
I have contacted meade and have a return auth number.
If I use an alignment tool for refractors (shorter than the chesire) the misalignment is harder to see. This tool is about the length of an EP.
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Stuff to look at stars and things
Scopes For Kids Project
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John Carruthers
Skiprat
Reged: 02/02/07
Posts: 2270
Loc: Kent, UK
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Quote:
Hi John,
Thank you for your reply and suggestions.
I guess I do not quite understand what "front end droop" is. Could you elaborate on this a bit?
Thanks,
Mark J.D.
On the refractor ETX's the focus mechanism moves the objective toward and away from the eyepiece. At full extension the objective tube droops noticeably making collimation impossible. The Maks have a different system I believe.
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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
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StarWars
Postmaster
Reged: 11/26/03
Posts: 13796
Loc: CyberSpace
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FYI
When Maksutovs are collimated, particularly with computerized optical
benches, they are typically done so exactly at the precise focal plane;
the nature of the primary shifting as it achieves focus or either way
inside or out, will result many times in the fact that ONLY at the exact
focal plane is the scope in precise collimation!
Thus, you may have extremely good collimation and yet your out of focus
star image suggests that it is not. To test, merely aim the scope at a
2nd magnitude (not brighter) star nearly directly overhead and
center....do not test with it even slightly to one side of dead center.
ETX Collimation 
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