Telescope Reviews: PEC on Meade LXD-75-does it work?

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Richard Turner
super member

Reged: 01/25/09

Loc: NC

PEC on Meade LXD-75-does it work?
#3145847 - 06/04/09 04:10 PM

This question might have been addressed before. I have an LXD-75 mount. The manual says to "park" the scope to train the PEC. I did that, and trained the PEC on a guide star with an illumintated reticle.

After the training the mount did not track any better than with the PEC turned off. Am I missing something, or does the PEC function just not work?

Thanks,

Richard Turner

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hfjacinto
I think he's got it!

Reged: 01/12/09

Loc: Land of clouds and LP

Re: PEC on Meade LXD-75-does it work? new

[Re: Richard Turner]
#3145856 - 06/04/09 04:13 PM

I trained PEC on my LXD 75 and it didn't do anything. The scope tracked nice before, it still tracks nice.

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jrcrilly
Refractor wienie no more

Reged: 04/30/03

Loc: NE Ohio

Re: PEC on Meade LXD-75-does it work? new

[Re: Richard Turner]
#3145897 - 06/04/09 04:32 PM

Quote:

After the training the mount did not track any better than with the PEC turned off. Am I missing something, or does the PEC function just not work?

What tracking error were you noticing before? If was DEC drift it'll still be there; that isn't related to periodic error.

Post Extras:

Richard Turner
super member

Reged: 01/25/09

Loc: NC

Re: PEC on Meade LXD-75-does it work? new

[Re: jrcrilly]
#3146047 - 06/04/09 05:58 PM

John,

I had the scope fairly well polar aligned, and the drift was in RA, east-west, due to the periodic error in the worm. Another poster related that their LXD-75 tracked nice. The tracking in my unit was also quite good. I just thought PEC might improve it.

Richard

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jrcrilly
Refractor wienie no more

Reged: 04/30/03

Loc: NE Ohio

Re: PEC on Meade LXD-75-does it work? new

[Re: Richard Turner]
#3146142 - 06/04/09 06:48 PM

Quote:

the drift was in RA, east-west, due to the periodic error in the worm. Another poster related that their LXD-75 tracked nice. The tracking in my unit was also quite good. I just thought PEC might improve it.

Richard

It definitely should improve PE. If you could see PE in the eyepiece then it is very severe or you were using very high magnification, though. The key to distinguishing PE from drift is to check it 8 minutes apart. PE will repeat and the object will be brought back to precisely the same place. If it's drift then the object will move and never come back to the same place in the eyepiece.

Did you (1) train for one full worm cycle and then (2) wait through another until the next cycle after that? That's when the correction begins.

Post Extras:

Richard Turner
super member

Reged: 01/25/09

Loc: NC

Re: PEC on Meade LXD-75-does it work? new

[Re: jrcrilly]
#3146229 - 06/04/09 07:45 PM

John,

I did train for the entire cycle. After that I went from "PEC train" to "PEC on" to observe the results.
I did not see any improvement. Perhaps my polar alignment was not accurate enough.

Would this be the correct procedure for the next clear night?

1. Obtain a highly accurate polar alignment.
2. Make sure mount is balanced or with a slight levereage to
the east. Obtain a star alignment.
3. Observe the amount of period error amplitude on a star
near the equator with the 12mm illuminated eyepiece.
4. "Park" the scope.
5. Do "PEC train" for an equatorial star for the full worm
cycle.
6. After training, enter "PEC on" mode and observe if the
periodic error is reduced from non-pec.

Thanks,

Richard

Post Extras:

milky_way
member

Reged: 05/26/08

Re: PEC on Meade LXD-75-does it work? new

[Re: jrcrilly]
#3148118 - 06/05/09 11:33 PM

Quote:

Quote:

After the training the mount did not track any better than with the PEC turned off. Am I missing something, or does the PEC function just not work?

What tracking error were you noticing before? If was DEC drift it'll still be there; that isn't related to periodic error.

Just wonder what is the reason causing a DEC drift and any solutions for such a problem?

Post Extras:

Richard Turner
super member

Reged: 01/25/09

Loc: NC

Re: PEC on Meade LXD-75-does it work? new

[Re: milky_way]
#3148238 - 06/06/09 01:44 AM

I'll try for a very accurate polar alignment to greatly reduce declination drift. I think the scope is supposed to be parked after the PEC is trained. The hand control prompts that the scope should be turned off after parking. Upon power up, the PEC should work.

Post Extras:

Richard Turner
super member

Reged: 01/25/09

Loc: NC

Re: PEC on Meade LXD-75-does it work? new

[Re: Richard Turner]
#3152910 - 06/08/09 07:38 PM

Well, I found out that the PEC does indeed work. I tried a training session, then parked the scope. Upon power up, the PEC then worked.

R. Turner

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