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LX200R PEC Training

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#1 d_calleja2003

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Posted 23 December 2012 - 12:59 AM

Cloudy last weekend so I thought I would re do my PEC training in between cloud banks. It looks a lot better than what I've achieved before but I had not thought the result could be so effective

I used Pempro and my ST8300 for the training - results attached after one 48 min training session

What have others achieved with LX200's and how often should I retrain? Also does the PE vary with different pointing positions

Dan

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#2 akjudge

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Posted 23 December 2012 - 10:19 AM

Dan,

This is what PemPro did for my LX200R:

Jim

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#3 d_calleja2003

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Posted 23 December 2012 - 06:35 PM

Jim
Thats great. Do you retrain PEC often?

#4 akjudge

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Posted 24 December 2012 - 08:12 AM

Dan,

I retrain about once a year, but not real sure it is needed since my optical train rarely changes and my scope is very well balanced (3D).

As far as PE varying with different pointing positions, if I understand the theory correctly, the PE should not vary, since the error is in the motors/encoder and not dependent on position.

But like many other things .... I could be dead wrong...

Jim

#5 Markigno

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Posted 27 December 2012 - 07:43 AM

As far as PE varying with different pointing positions, if I understand the theory correctly, the PE should not vary, since the error is in the motors/encoder and not dependent on position.

But like many other things .... I could be dead wrong...

Jim

yes, it is wrong. the PE is given by the imperfection of mechanical processing of the worm screw. In addition, mechanical imperfections of the gear, also affect the PE. Encoders and motors do not affect the PE. In other words a position very different from the formation PE could give different results, precisely because of the different position of coupling between the worm and gear wheel.
Marco

#6 akjudge

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Posted 27 December 2012 - 10:37 AM

Marco,

Thanks. I misspoke by not including the worm screw, which obviously is the basis for PE. However, I fail to understand how a scope position, say pointing Southeast at 30° declination will produce a different PE than pointing the scope to the Southwest at 15° declination. If that is the case, one would have to have a different PEC for every scope pointing direction (infinite number).

Since the worm gear cycle will be the same over a given period of time, irrespective of where the OTA is pointing, one does not have to do a PEC for every possible pointing direction.

But as I said earlier, I could be dead wrong.

Jim

#7 Christopher Erickson

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Posted 27 December 2012 - 02:00 PM

Marco,

Thanks. I misspoke by not including the worm screw, which obviously is the basis for PE. However, I fail to understand how a scope position, say pointing Southeast at 30° declination will produce a different PE than pointing the scope to the Southwest at 15° declination. If that is the case, one would have to have a different PEC for every scope pointing direction (infinite number).

Since the worm gear cycle will be the same over a given period of time, irrespective of where the OTA is pointing, one does not have to do a PEC for every possible pointing direction.

But as I said earlier, I could be dead wrong.

Jim


There can be differences but they are usually dependent on balancing, which can cause differences in gravitational loading on the worms and drive trains.

#8 JR#8

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Posted 01 January 2013 - 12:39 PM

I've Had my scope since 2004 and never did a PEC. Wouldnt even know where to start. Is it really necessary? I'm trying to get into astrophotography, at this point i'm having trouble with the focus even with a B-Mask. I think its the DSLR.

#9 Christopher Erickson

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Posted 01 January 2013 - 07:40 PM

I've Had my scope since 2004 and never did a PEC. Wouldnt even know where to start. Is it really necessary? I'm trying to get into astrophotography, at this point i'm having trouble with the focus even with a B-Mask. I think its the DSLR.


PEC is only important to astrophotography. And yes, PEC training will improve the sharpness of your images.

Focus is always a big challenge for astrophotographers. Aids help a lot but nothing replaces practice.

Images Plus has all kinds of dSLR utilities, including focus.

#10 JR#8

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Posted 01 January 2013 - 08:11 PM

i'll have to check it out

#11 RedLionNJ

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Posted 02 January 2013 - 09:14 PM

I'm not deliberately trying to hijack this thread, but I have an observation and a question which may (or then again, may not!) be relevant...

I have an ACF and was redoing my PEC this evening, as I do every six months or so. This evening's result was rather splendid on the graph, as it reduced a very wavy line of perhaps +/- 30 arcsec or so down to +/- 1.5 arcsecs. Probably my best ever, in fact.

Then I slewed to an object at a different altitude and found immediately my PE was shot again, actually WORSE than if the training had never happened. I confirmed RA PEC was still enabled, etc. No clue what's going on.

Anyone else experienced this after a slew? Is it possibly my handbox is corrupted in some way?


Thanks,

Grant






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