Metaguide vs PHD2 Generic equipment discussions · Himanshu Pandey · 14 days ago · 28 · 1251 · 0

I use the Ekos guider and it works better for me. Calibration seems to be more flexible and faster, the interface is more straightforward, and I think I get better results.

I used to switch between PHD2 and the Ekos internal guider, and with the same settings for calibration and guiding parameters, same results in guiding.

Or I should say I got similarly bad results with my strainwafe mount (WD17). Just dreadful amounts of periodic error. Had many occasions where PHD2 PPEC was not able to lock into the major period of the RA oscillation, so ended up with a good starting value from PHD2 frequency analysis, used this as a starting point in Ekos GPG, and used the resulting period in PHD2 without adaption. 

Then after the last KStars update, which changed the way Ekos calculates the RMS error so it’s in line with the way PHD2 calculates it, same results still. Until I accidentally deleted my equipment profile, and had to make a new one from scratch, haven’t seen guiding deviations above 0.4” since. Cannot find what changed. 

More on topic, is the use of single guide star, single guide star with lucky imaging or multi star. With a low powered mini PC, and a SW mount that needs frequent correction, multi star guiding is notably slower. Depending on seeing conditions I got the best results with either single star with frequent corrections, or multi star with only 5 stars and a 50% lower correction frequency. I assume single star with lucky imaging could give the same results as multi star, as long as the algorithm is fast enough. But there’s no way to use lucky imaging in guiding on Linux yet.  Would be interesting to try out. 

Last five night, and probably the next five nights as well, seeing has been good, even excellent for my location. So I’ll stick with single star guiding since it gives me good results right now.