periodic error

[kimo]

Very Good job. Now waiting for astrophotograph from you.

[rcj]

some things to note for PECPREP analysis, best to choose star near meridian and as close to 0 declination. As advised prior from the first poster, get at least 1/2 hour of data, although nowadays, it might be a challenge due to passing clouds. It is good to keep the gears clean and lube them, but also to ensure that the meshing is sufficient (one 80-gsm paper width gap between gears in Vixen mounts, etc.)....

[orly_andico]

Yup you need at least 2-3 worm cycles. a 55-sample run does not give any meaningful data (that's 1 minute!) because the worm cycle is 10 minutes.

[rcj]

will be looking forward to using pecprep to do some analysis on the new mount at my end. Meanwhile, has anyone tried using its generated PEC curves with much success?

[PETER LOO]

You are right, Sifu Remus & Sifu Orly, i took a more complete cycle using Algol (compensated DEc 41 Deg) as the sky was quite cloudy then, results of the GPD2 Un-guided is around 43 Pk to Pk, whereas for GP2 is around 54 like what Orly said for the GP. No worry though, i can still continue to use the 'UN-GUIDED" mode since the "gradient" of the slope for 1.5 mins is less than 10 Arc Sec(see 90s timebase segmentation) for GPD2. What i would do is to stretch the usable un-guided time by combining 1.5 mins & 2.0 mins shots, averaging them still looks okay for me. Why i so hardup (obsessed) in using "UN-GUIDED" mode here is because the cloud formation in SG & Johor is like crazy, thus disturbing proper guidance and often star lost.

[orly_andico]

Hm.. Frankly I am surprised that the GPD2 is +/- 20. I would have expected it to be +/- 10. Lots of folks on the CN forum have told me that.

Are you balanced slightly east-heavy? if the mount is west-heavy i.e. it is "falling" all the time, the PE gets significantly worse. So the mount must be slightly east-heavy.

I understand about wanting to go unguided - it is not susceptible to the guide star getting lost. What I have seen is that PHD does not react well to losing the guide star (it does large slews which upsets the long exposure). However Maxim can react to lost stars much more gracefully (it simply stops guiding).

[PETER LOO]

Hi Orly, did not check for balance, it could be slightly off but shouldn't be too far, as for the lost star problem, thanks for the enlightenment, will try using MaximDL5 next round although it looks less user friendly, after all already spent a heart ache amount of SGD to fully up-grade the software package, as for now, running off to work (2nd shift), see you, cheers