PEC Recommendations

[Juno16]

Hi Everyone,

I have been cruising along enjoying my new adventures in AP. Still have a huge learning curve in front of me

My images so far have been okay. Many small issues, but things are going pretty well and I am having a great time. Just not enough clear nights!

I am at the point where I want to try some PEC. My guiding with the AVX has been fair. Getting the job (or most of the job) done, but my biggest guiding error is by far RA. I have large and small fluctuations.. Some of it may be repetitive and benefit from PEC. I know that there is a recording routine in the HC, and I know that Celestron has a PECTool free download. The PECTool is quite dated from what I can tell.

I am looking for something fairly simple that does not require a bunch of fuss (and preferably free).

Any recommendations?

Thanks!

Jim

[UlteriorModem]

Are you using PHD2?

If so can you put a log file up on drop box or something to have a look at?

It has been my experience that fussing with PEC while using guiding actually made things worse. You see the PEC routine, and the guiding software are often at odds with one another.

Far more important is your polar alignment, balance, and the mounts 'awareness' of where it is pointing.

[Juno16]

Hi Tom,

Yes, I am using PHD2. Here is a link to my last guide log.



I do know that my AVX mount has a lot of PE. Does PHD2 "learn" the periodic oscillations and correct for them on the fly? So, if you are using PHD2, there really is no need to run PEC?

Thanks,
Jim

[JayTee]

The general rule of thumb over at the PHD2 Google group is to perform your PEC recording (evoked in the HC) during a NO guide session. Then for your follow-on images "playback" your PEC while using the "Predictive PEC" guiding algorithm in PHD2. Always run the GA after you've made changes like this. According to the authors of PHD2, this will give you the best results. Let us know how this works. BTW, my RA axis on my AVX mount is ALWAYS the limfac for the length of exposure of my images.

Cheers,
JT

[Juno16]

Hi JT,

Thanks for the info!

Just to be clear, I am to use the HC to record the PE, start PEC playback on the HC, start guiding. Run the GA and accept the recommendations, then calibrate PHD2. Then, on to guiding and imaging.
Did you see an improvement using PEC on your AVX?

Yes, my RA error is sometimes double my DEC error. If you look at the guide log, you will probably be amazed that I can get fairly decent stars. They aren’t perfect, but decent.

I will get back as soon as I try it out. Unfortunately, the weather is rainy here for the next few days and I am flying to Santa Barbara next week for a week, then driving home from there. Unless I get lucky soon, I won’t be imaging for a bit.

I really appreciate the info JT!

Thanks,
Jim

[Stuart]

I am a HUGE fan of PEMPro. Super easy to use.
http://www.ccdware.com/products/pempro/

[JayTee]

Just to be clear, I am to use the HC to record the PE, start PEC playback on the HC, start guiding. Run the GA and accept the recommendations, then calibrate PHD2. Then, on to guiding and imaging.
Did you see an improvement using PEC on your AVX?

Yes, except that when you do the calibration is not important in the process of switching over to Predictive PEC and the running the GA.

JT

[JayTee]

Hi Stuart,

PEMPro only works on the Celestron CGE mount and no other. We Celestron users don't get the benefits that PEMPro offers.

Cheers,
JT

[Aidi]

I played with PEC only recently having bought a EQ6 R Pro as it can store the PEC tot the encoders.. Prior to that, any PEC I did was lost when I moved the mount as I always forgot to park at the end of a session.

If I’m honest, I’ve not seen a huge improvement since using it on my mount...That’s not to say it might not help others. It was something easy to do and see what happend!

[UlteriorModem]

Hrm I was un able to open the log file with PHD Log viewer. And when I went to look for a 'new' version it (the log viewer) seems to have vanished from the interwebs.

Oh well. The OP had received good advice and guidance (pun intended)

Does PHD2 "learn" the periodic oscillations and correct for them on the fly? So, if you are using PHD2, there really is no need to run PEC?

No and yes, it does not 'learn' the PEC curves, but it does attempt to correct for them 'on the fly'.

Some say it's best to just let PHD do its thing. Others say it's best to help PHD do its thing.

Go ahead and try it cant really hurt anything. I just never had any success or saw any improvement with it.

[Juno16]

Thanks everyone for your help and experience!

I will give PEC a try. My AVX definitely has some oscillations in RA and I’m sure that some of it is PE related. The rest is probably in the gearbox. I have read a good bit about PEC on an AVX mount on the internet and the results have been overwhelmingly favorable.

I will post my experiences, but unfortunately, it might be several weeks before I get a chance to test.

Thanks all for your experiences. Thanks JT for the details.

Jim