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Meade etx 90 polar alignment


Lordspace

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Forgive me if this is in the wrong place but it is to do with my mount in a sense.

Anyway...

I have tried to out my ext90 into polar home mode using the methods online and I believe I have everything setup.

But I must be missing something as when I start say,the easy alignment it will miss the first star by alot.

Then once it thinks it's done if I then proceed to say pick the Orion nebula it is always way off where it actually is.

 

Anyone had success with this mount??

 

Cheers

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Don't post similar requests in different parts of the forum.

Have you Trained Drives ?

Carried out RA and Dec Backlash correction ?

Excess Meade grease might have got onto the optical sensors that "count" how far the mount has moved when it's doing a GoTo.

Michael

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  • 10 months later...

Howdy,

Just to start off on the right track I'm new to telescopes so don't assume I know anything ;.).  The ETX 90 is my first telescope and I'm enjoying it.  But I decided to try astrophotography.  But I thought I would see if I could Polar alignment my scope first.  I have a fairly good understanding of the nights sky.  I have a few questions:  First after I level the base and set the wedge to my latitude I rotate the the scope up to set the DEC and making sure the scope is facing up and level the scope seems to be backwards.  If I then point the scope at Polaris The scope is upside down.  So I must be doing this wrong.  I'm ready the Page from the "Arkansas Sky Observatory."

Another question I have is I read before alignment you should rotate the mount clockwise to the stop.  I unlock the base and rotate it but I never come to a stop.  So I must be doing something wrong again. 

So thanks in advance for any and all replies.

Ed

 

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Hi Ed

Years since I had an ETX125, so from memory here goes:

There are RA stops in the base. 

Rotate it by hand, unclutched, one way until you hit a stop,

Then rotate the other way until you hit the other stop.

Then put it halfway between, but offset so that it's pointing north when the low end of the wedge is pointing north.

Finder should be on top.

Check it's in Polar mode on the handset.

When you first switch on, the mount assumes you are pointing at true north, not Polaris.

During Star Alignment, when prompted centre Polaris with the wedge Alt, and Az by nudging the tripod east or west.

Then centre the next star with the handbox, and then ENTER.

Michael

 

 

  • Thanks 1
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Hello Michael,

I have rotated the base counter clockwise several times, uncluthed, and have so far not hit a stop so I'm not sure how many turns it takes to hit a stop.  I'm also afraid if I keep turning it I might some how damage it.  Or perhaps something is already broke????

Thanks for your response.

Ed

 

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Hello Michael,

I tried the other direction and there is no stop there either.  So it sounds to me like the unit is broken???  What next?

This is probably why the unit will not track correctly.  I noticed when using the finder scope and trying zero in on what I'm looking at the down arrow key that points to the bottom of the AudioStar does not do anything, or is this because I Polar aligned the scope?  After turning off the AudioStar and bringing my scope back into the house I turned AudioStar back on and tried the down arrow and the scope did slew downward.  So the gear works it's just does not work when I'm trying to zero in the alignment star.  On my second attempt the scope slewed to Capella but It was not even close.  I'll set up again tomorrow.  I am using PS Align PW to check my manual alignment to Polar home and I'm very close so I'm not sure what I'm doing wrong.

Thanks,

Ed

 

Edited by EdDoyle
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And you have the Slew Speed at a higher setting than default eg SPEED then 9 ?

Is the mount tracking in RA (following star movement across the sky) ? 

The RA will start tracking if you skip Alignment, just enter Time and Date then MODE out to OBJECT.

Then unlock Dec and RA and Relock after centring a star.

Michael

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Hi Michael,

 

Thanks for your help.  I think the first thing I might try is to train the gears.  I have not done that and I bet that might help out.   I'm also going to check the slew rates as well.  Then I try the things you have suggested.  Somewhere in the middle I hope to find the problem.

Ed

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