Can't get PEC Training to work on LX200 ACF, need help!

[StevenSWissler]

I mostly use my telescope for visual and planetary/lunar photography, will eventually ( when funds are available ) get a wedge and try deep-sky photography. I've tried twice to do the PEC training in Az/El, once using an illuminated reticule eyepiece, and once using a DSI II with autostar guiding. Both times resulted in strange behavior. The first time, after the training in Az and El, then turning PEC correction on, the scope failed to track, it appeared that the PEC had resulted in a 2x or 1/2x drive rate. The second time, with the autoguider method, the star seemed to track pertty well with autostar guiding with the DSI. I read the resultant PEC curves into the MyScope PEC editor and it laughed at me 
It looked like the PEC was the gear position? , went something like +/- 600.

Has anyone seen this behaviour before? What am I doing wrong?

[Toxo]

Steve,

I don't want to come off like a curmudgeon on this issue - I own two Meade telescopes and three of their cameras - but trust me, get PemPro and be done with it.  It works so much better than the factory PEC that I don't even think it is worthwhile to try.  Get a Wedge, get PemPro, and relax!

Good luck,

Toxo

[StevenSWissler]

The wedge is my next major purchase, but until then I was hopping to improce the alt-az tracking for lunar / planetary and visual work. The scope tracks pretty well as is, was just hoping to get some improvement, if possible.

[akjudge]

Steve,

PEC is misunderstood by a lot of people, and that leads to a lot of confusion and disappointments (since their expectations are unrealistic).

PEC is designed to correct short term errors so that if you're using a guider, it only needs to make slow gradual corrections for the longer term errors. It also allows limited unguided deep sky imaging since the useful time for unguided exposures is extended from a few seconds to maybe 1 minute. But long term errors still need to be handled by guiding if you want to use exposures longer than about 1 minute.

PEC has little if any effect on Lunar/planetary work, since lunar and planetary movement is different than stellar movement (relative to your position) that PEC tries to correct for.  Lunar/Planetary "drift" is always going to be  worse than any star 'drift" since the tracking rates are not the same.  Meade tries to get you close by giving you a Lunar tracking rate option.  Just remember this is a "best guess" rate, since the rate will vary depending on moon location, etc.  Lunar/planetary tracking rates will always be off-over-time.

Toxo is absolutely right when he says to get PemPro for PEC training.  Meade's PEC training HAS KNOWN BUGS AND SHOULD NOT BE USED.  It can lead to disasters -- for more information check out the LX200 GPS Yahoo Group (search for Meade PEC training).  Just be sure that PEC training will do what you need, before going through the effort, and being disappointed when the results do not match your hopes.

PS:  Just re-read this before posting.  Didn't mean to sound negative or too assertive.  Bottom line =   (1) Meade PEC tool is BUGGY and can lead to real problems; (2) PEC training is not needed for visual or lunar/planetary work.

Jim

[StevenSWissler]

Thanks for the info, I intend to get PEMPro once I have a wedge, since PEMPro does not work when the mount is in Az/El. I was hoping to improve the general tracking performance in Az/El by doing the PEC training. I may have gotten a good PEC training the other night, by using Meade's PEC training and guiding with my DSI and PHD. I need another clear night to check it out. It would certainly be unfortunate if the Mead PEC training is buggy and they don't fix it...

[StevenSWissler]

Seems like Jim is absolutely right. The Meade PEC training does not work. I tried it three different ways, using an illuminated reticle, and guiding manually, using a DSI/autostar to guide, and using a DSI/PHD guiding to guide. Then, turn PEC on and watch a target drift out of the field of view.

Does anyone at Meade have a comment on this? It's a shame that such a potentially useful feature would not work correctly.

[akjudge]

Steve,

I am a BIG fan of Meade.  It gives the best value for the dollar across all of it's product line.

However, the PEC tool Meade provides does not work.  And they have known about it for years.  Don't hold your breath for a fix.  It is as likely as a LPI driver for Vista...

There is a work-around.  PemPro, which most of us use to fix the factory PEC settings in our scopes, gives you a free 30 or 60 day trial of the full feature version.  Some people will put their scope on the wedge, then use the free trial period to fix the factory PEC settings for their particular scope.

This works since the PEC will not change if you do not change the gears, such as adding Buck gears, etc., although it is possible that the PEC could change if you added a real heavy camera...  But for most people when you get the PEC corrected via PemPro you do not have to do it again -- it is a one-time fix.

Having said that, (and having done exactly that), I liked the damn program so much I went ahead and bought it anyways.  NOTE:  PemPro also has a great Backlash corrector and an equally great Polar Alignment Program in addition to the PEC tool it is so famous for.

Don't worry about PEC until you decide to do long-exposure astroimaging (>2 min exposures), since there is no real effect on short term imaging (webcams) or visual usage.  Once you commit to longer exposures, PEC is very important.

Once you take this leap (expensive!), get a wedge, then PemPro...

Jim
 

[StevenSWissler]

Thanks Jim, that's my long term plan, get a wedge and Pempro...

[Mark Sibole]

You MUST be on a wedge to use the PEC feature.
It does no good or I dont think it even works in ALT/AZ mode.

Regards

Mark