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LXD75 all wacky...

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#1 MtnGoat


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Posted 08 April 2009 - 05:36 PM

So, I'm getting weird goings on with my LXD75. I do a three star alignment and the polar report tells me I'm two degrees off in one direction and a half degree off in the other. That's weird. Last time I got the 'less than 5'' message and I haven't changed anything.

I go use it and the GOTO's are terrible. All a couple degrees off.

Next night, I go out and do a three star again, this time I get the 'less than 5'' off message, and the GOTO's are dead on.

Anyone else run into anything like this? I checked the encoders last time I had it apart and there is no crud in there at all. I did however do a drive cal before the align the last time, however.

#2 fetoma



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Posted 08 April 2009 - 06:58 PM

ALWAYS train your drives and calibrate the motors EVERY time out before aligning.

#3 jgraham


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Posted 10 April 2009 - 07:28 AM

Hmmm, when things get whacky (and you've got a solid power supply) it's usually time for a reset and start over.

As footnote, I just use my polar scope to align my mount (and the polar scope as been aligned as per the manual) and a two-star alignment. When I'm done for the night I park my scope and bring things back inside. The next time out I just polar align, GoTo a bright star, and synch the mount. No other alignment. I calibrate and re-train maybe once a year and I re-do the two-star alignment every couple of months or if I do something stupid that messes up the alignment.

If you're looking at the encoders, make sure there's nothing hiding between the light source and the detector; the encoder wheel itself might be clean but there could be a dust bunny stuck between the emitter/detector.

#4 MtnGoat


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Posted 10 April 2009 - 12:24 PM

ah, good point john. hadn't thought about making sure the detectors are clean on both sides.

this setup is fixed on a pier, and left polar'ed when I'm done, so that eliminates set up error as a problem here. I pull the OTA and cover the mount after I park it.

Currently I have two OTA's I run on it, an SN8 and a 120mm F5 refractor. The SN8 has been getting most of the play lately, and I usually retrain when I switch OTA's because I need to rebalance anyway and I might as well.

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