PEC Prep

[alan potts]

OK as next to useless as I am at this computers lark I do try in my own little way to improve, and I feel I am, guiding now and getting round stars even have very good goto. Thanks to help from 2 very kind Davids  on site I have nailed (I use that in the loosest sense of the word) dither, well tacked it down may be more accurate.

Right PEC Prep, is it worth doing for a fixed mount and if so does anyone know of either a video or instruction aimed at the likes of me to tell me how to record a file. The PPEC in the mount now I imagine with the use of EQmod is no good. Mount is EQ AZ 6 GT

Any advice would be welcome, even if you tell me to forget it.

Alan

[Allinthehead]

I use the same mount Alan and i've often wondered whether this was worthwhile. Given that i use short sub exposure times i never bothered to experiment. Would certainly be of interest to see if others had any positive experience. It's not something i see mentioned on the forum often.

[alan potts]

22 hours ago, Allinthehead said:

I use the same mount Alan and i've often wondered whether this was worthwhile. Given that i use short sub exposure times i never bothered to experiment. Would certainly be of interest to see if others had any positive experience. It's not something i see mentioned on the forum often.

Yes I had a look around first and didn't see anything. I have video by some guy in the US where he run ST4 guide and handset but with EQmod now being used and some half decent guide I am reluctant to change anything, someone MPéd me and said he had tried and found it hard work, so for sure I will, he actually gave up. I guess if stars are round and guide is OK what's the point, guess I am just trying to be too clever for my own good.

Alan

[Allinthehead]

Ya i reckon keeping things as simple as possible is the way to go. If your guiding is good and stars are good then no point changing anything.

[alan potts]

The one thing I would like to change is the weather, very poor May here so far and April was nothing to write about, most un-Bulgarian like. Still at least I can say the moon is spoiling things the last few days so not so bad, hope I don't forget what to do when I do get going again.

Alan.

[wimvb]

I have the same mount model, and so far haven't had any luck with ppec. I've tried the manual way and tried with phd to no avail. But one thing which has improved guiding is the use of the predictive pec guide algorithm in phd. It compensates to some degree, a 2 minutes period I have in RA. The algorithm measures the ra deviations and corrections while guiding. As imaging time progresses, it uses the information to compensate for periodic error. PEC on the fly, you might call it.

[tooth_dr]

1 hour ago, wimvb said:

I have the same mount model, and so far haven't had any luck with ppec. I've tried the manual way and tried with phd to no avail. But one thing which has improved guiding is the use of the predictive pec guide algorithm in phd. It compensates to some degree, a 2 minutes period I have in RA. The algorithm measures the ra deviations and corrections while guiding. As imaging time progresses, it uses the information to compensate for periodic error. PEC on the fly, you might call it.

Sorry if this is a simple Q, but how do you do that.  The drop down box for algorithms on mine is greyed out.

[wimvb]

4 minutes ago, tooth_dr said:

Sorry if this is a simple Q, but how do you do that.  The drop down box for algorithms on mine is greyed out.

It is, sometimes. But if you are connected and stop looping, it should be available afaIk.

[tooth_dr]

1 hour ago, wimvb said:

It is, sometimes. But if you are connected and stop looping, it should be available afaIk.

I’ll check that later. Thanks. 

[alan potts]

 

12 hours ago, wimvb said:

I have the same mount model, and so far haven't had any luck with ppec. I've tried the manual way and tried with phd to no avail. But one thing which has improved guiding is the use of the predictive pec guide algorithm in phd. It compensates to some degree, a 2 minutes period I have in RA. The algorithm measures the ra deviations and corrections while guiding. As imaging time progresses, it uses the information to compensate for periodic error. PEC on the fly, you might call it.

I will take a look at that and see if I can do anything. What I did play with last night was the PPEC box in EQmod, didn't know what I was doing mind you. I run the mount in the ticked box Record PPEC mode for about 6 minutes or so. Whilst it was tracking the light on the mount was flashing a morse code like pattern, the after the 5-6 minutes it stopped. I then ran it ticking the other box run PPEC. In this time I had some very good guiding which was spoilt only by me not allowing enough dither time for fairly long periods I was getting better than 0.4 of sec on RA. I didn't get to run for long, only 40 mins as a thunderstorm rained on my parade. I manually stopped the APT opening the shutter for the last 5-6 captures and guiding was by far the best I have had. Dither is working for sure but seems to take longer the longer it runs, not had a look at the 15 captures yet but on screen they looked very good.

Goto pointing is now bang on too, now the trouble is I am reluctant to change a scope over to another for want of messing things up, wish I could get some better weather, really poor this year and seeing last night was superb.

Alan

[wimvb]

1 hour ago, alan potts said:

What I did play with last night was the PPEC box in EQmod, didn't know what I was doing mind you. I run the mount in the ticked box Record PPEC mode for about 6 minutes or so. Whilst it was tracking the light on the mount was flashing a morse code like pattern, the after the 5-6 minutes it stopped. I then ran it ticking the other box run PPEC.

I must try that when it gets dark enough again (end August). I used the INDI version of eqmod when I played around with ppec, but never got it to record. I will try with the Windows version next (which I assume that you used). How did you use the ppec option in eqmod? Setting up guiding with phd and then just start ppec recording? Did you use ST4 guiding or pulse guiding through the mount's serial connection?

Edited May 23, 2019 by wimvb

[alan potts]

2 hours ago, wimvb said:

I must try that when it gets dark enough again (end August). I used the INDI version of eqmod when I played around with ppec, but never got it to record. I will try with the Windows version next (which I assume that you used). How did you use the ppec option in eqmod? Setting up guiding with phd and then just start ppec recording? Did you use ST4 guiding or pulse guiding through the mount's serial connection?

You've got to realise I don't know for sure that I got EQmod to do anything but there were signs something happened. Whilst I was waiting for it to be dark enough I slewed to where I want to be and turned tracking on, goto is very good now. In EQmod I checked the box marked Record PPEC and notice the red light on the mount was flashing an pattern of some sort. This went on for about 5-6 minutes, maybe a bit longer, then stopped and the lamp was steady red no flashes. When it got dark enough I started guiding and checked the other box directly below the Record box and unchecked record, I can't recall what it is labeled but it's something PPEC, the mount lamp then again started flashing away, so something was happening. I was using pulse guide via EQdir cable. Hope this is of some use, I will monitor progress to see if it works.

I didn't get as good a guide on my last 2 shots on M57 but this was really low (0.8 sec RA), 15 degrees maybe, it was only done because of cloud but stars did look round.

Alan

[wimvb]

2 hours ago, alan potts said:

I slewed to where I want to be and turned tracking on, goto is very good now. In EQmod I checked the box marked Record PPEC and notice the red light on the mount was flashing an pattern of some sort. This went on for about 5-6 minutes, maybe a bit longer, then stopped and the lamp was steady red no flashes.

Flashing is more than I got, other thsn wsiting to start ppec training.

But if you only tracked without guiding, no corrections were sent to the mount, and the pec dataset would be empty. AfaIk, it's the guiding data that gets stored in pec memory. No guiding, no pec. When replaying pec, you'd expect fewer guide pulses to be sent to the mount from phd.

Another thing that puzzles me is the timing you describe for the recording phase. According to the AZ-EQ6 manual, the mount first looks for the worm index, which can take up to one worm period. And this period is about 8 minutes. It would take this long to record the curve.

This is what it says in the mount manual (regarding flashing of the power led):

4. Intermittent  one  flash:  The PPEC training routine has been triggered, but the controller  in the mount has not received  the worm index  signal  and  the correction-recoding has not started yet.

5.  Intermittent  two  flashes:  The PPEC training routine has been started and the controller  in the mount has received  the worm index  signal  and started to record the  PE  correction.  When  the  intermittent  two  flashes  stops,  it  means  the  PPEC training has finished.

6.  Intermittent, three flashes: Sidereal tracking with PEC is now enabled.

 

Edited May 23, 2019 by wimvb

[alan potts]

5 hours ago, wimvb said:

Flashing is more than I got, other thsn wsiting to start ppec training.

But if you only tracked without guiding, no corrections were sent to the mount, and the pec dataset would be empty. AfaIk, it's the guiding data that gets stored in pec memory. No guiding, no pec. When replaying pec, you'd expect fewer guide pulses to be sent to the mount from phd.

Another thing that puzzles me is the timing you describe for the recording phase. According to the AZ-EQ6 manual, the mount first looks for the worm index, which can take up to one worm period. And this period is about 8 minutes. It would take this long to record the curve.

This is what it says in the mount manual (regarding flashing of the power led):

4. Intermittent  one  flash:  The PPEC training routine has been triggered, but the controller  in the mount has not received  the worm index  signal  and  the correction-recoding has not started yet.

5.  Intermittent  two  flashes:  The PPEC training routine has been started and the controller  in the mount has received  the worm index  signal  and started to record the  PE  correction.  When  the  intermittent  two  flashes  stops,  it  means  the  PPEC training has finished.

6.  Intermittent, three flashes: Sidereal tracking with PEC is now enabled.

 

I have told you before I am far from being expert, I know nothing. The good thing is I've got you thinking with much great Guide knowledge, lets hope between us we can get something sorted and working. On the bright side as it would appear I did absolutely nothing in relation to PPEC other than pass time, the mount performed very well indeed, so well I am sure some would ask why bother, Olly said to get down to 0.5sec in both RA and Dec is about as good as one can hope for, I was a bit better than this alot of the time.

As for the flashes I would say I was getting intermittent two flashes. I will try this again, don't cost anything does it. Please let me know how you fair, looks li9ke weather is poor again here.

Alan.

[wimvb]

I too think that we should be able to work something out.

1 hour ago, alan potts said:

Please let me know how you fair, looks li9ke weather is poor again here.

Unfortunately here it's not so much the weather as it is the absence of darkness that puts experimenting on hold. We won't have proper darkness until end August and I have my gear in storage now. But I could set up just the mount and guide scope for testing during summer recess.

[alan potts]

13 hours ago, wimvb said:

I too think that we should be able to work something out.

Unfortunately here it's not so much the weather as it is the absence of darkness that puts experimenting on hold. We won't have proper darkness until end August and I have my gear in storage now. But I could set up just the mount and guide scope for testing during summer recess.

Wim, I am pretty useless when it comes to using programs and IT in general but I am getting to know a few bits and pieces now I have had chance to use them for a while. I am the sort that learns quickly when someone shows me something and sadly here there is no one. In some ways that's good as I live in a remote area compared to say Hull or Leeds which is and is near to where I was before.

I will do what I can and Message you with findings, I will take notes as to what I did, when I get a chance to actually do something again and let you know. Someone did actually PM me and let me know recording a file in PecPrep and loading it was beyond his ability to get to work, so gave up, I would be to first to say his IT ability out shines mine for sure. Whilst this method of PPEC may not be as good, it may also offer a little help and every little bit working for you is better than against. The weather here is normally very good with lots of clear nights at this time of year and my biggest problem is stopping the mosquitoes biting me, I think this year most have drown.

The first thing I will try is recording PPEC whist guiding with PHD, could probably also image at the same time. Being very new to guiding there are a good few things that need that polish, like polar alignment and even scope balance though with the 0.5arc sec guide I was getting I am reticent to touch too much, I have other scope I wish to try and to be honest am worried about changing them for fear of messing things up. Also by August I will have funds in place to get the ASI 071, I would also like an ASI 183 as well and am having to fight off pressing the button with FLO to get it as I already have enough for that.

Alan