EQ6 PRO PE Error

[cardconvict]

Can anyone make sense of this data. I have followed a Youtube video from EQmod to get the data in PECPREP but i cannot make sense of it, is the mount good, average or bad ?

I have just completed a service on my mount and my images are not great even when guiding !!!!

[kens]

Not enough information. 

Is that a guided or unguided set of data? If unguided it is fabulous. If guided, you may need to adjust some guiding settings.

[cardconvict]

25 minutes ago, kens said:

Not enough information. 

Is that a guided or unguided set of data? If unguided it is fabulous. If guided, you may need to adjust some guiding settings.

This is a set of unguided information. It was captured with PHD 2 with the guiding signals turned off. If the issue is not with the RA it must be the DEC or flexure or incorrect balance. I will post a picture from last night.

[chrisshillito]

Was the capture declination really 0 degrees? or did you forget to set the declination as part of the PHD log import?

Also If you load the declination data form the same log do you get a straight line?  if not it may imply PHD hasn't measured the camera angle correctly during calibration.

Chris.

[cardconvict]

this was measured in RA in PECPREP my polar alignment error was huge and the dec line went straight off the graph, PECPREP corrects the lines and smooths them out and places it straight for you.  I think thats what you mean.

[kens]

I think most EQ6 owners would dream of +/- 3 arc seconds PE. Your problems lie elsewhere. Post the guide log so we can see the full picture

[cardconvict]

Here is 4 logs from the night for you to look at.

PHD2_DebugLog_2016-03-28_213130.txt

PHD2_DebugLog_2016-03-28_233437.txt

PHD2_DebugLog_2016-03-29_215006.txt

PHD2_GuideLog_2016-03-28_213130.txt

[theastrodragon]

2 hours ago, kens said:

I think most EQ6 owners would dream of +/- 3 arc seconds PE. Your problems lie elsewhere. Post the guide log so we can see the full picture

I must say, it seems unbelievably good for an uncorrected EQ6.

Even Paramount don't guarantee better than 7sec p-p for their high end mountings without PEC.

Was this done with PEC on?

[cardconvict]

No PEC was not on. I guided with a QHY5v, ST80 on the top of a C9.25. I can put the log file on here if requested

[theastrodragon]

4 hours ago, cardconvict said:

No PEC was not on. I guided with a QHY5v, ST80 on the top of a C9.25. I can put the log file on here if requested

Ah, so its +/- 3 sec when guided.

It could be you need to play with the guider.

Also, getting the data without guiding will show you if you have those nasty tracking spikes that are difficult to guide out. I'd suggest doing that first, as it will give a better idea of how to adjust the guide parameters

[cardconvict]

No the graph above was from PHD 2 without the guiding signals going back to the mount so it was not guided

[chrisshillito]

13 hours ago, cardconvict said:

this was measured in RA in PECPREP my polar alignment error was huge and the dec line went straight off the graph, PECPREP corrects the lines and smooths them out and places it straight for you.  I think thats what you mean.

If the DEC drift was a straight line then that's fine (you can change the scale the graph in PECPrep to make it fit on screen). If however the DEC graph has some periodic element to it that would imply that the PHD camera rotation angle isn't quite right and the true PE magnitude is being split into to spearate RA and DEC vectors which could explain why the RA amplitudes appear so small.

Also if the declination of your guide star was at anything other than 0, and and you don't enter this when importing into PECPrep, the calculated PE will be out by a factor equal to 1/cos(dec).

As you're using an EQMOD compatible mount why not use the AutoPEC feature to capture your PE whilst guiding? This method has the advantage that the log that is produced is in arcsecs rather than pixels so isn't dependent on declination or camera angle. Also because this works whilst guiding your star isn't going to drift of screen due to poor polar alignment. AutoPEC is covered in the EQMOD VSPEC document  (see EQMOD Project website - documentation page)

Chris.

[cardconvict]

Thanks for the advice it looks like it is going to be a clear night so will check this tonight

[kens]

It looks like you were guiding in the 20 minute run fro 22:50. The guiding was switched off at 22:54 and right away there was a huge drift in RA and Dec. When it came back on again at 22:56 the mount settled down again. 

Try running the guiding assistant - your aggression setting look a bit high.