PHD Guiding - that ping sound...

[Alveprinsen]

Ok, so PHD guiding plays that windows ping sound whenever it loses the star or whatnot.

I am currently using 2sec exposures with my Orion Starshoot Autoguider, and stars display relatively well through my 102/500 Startraveler scope which I use as guiding scope.

However, PHD guiding gives me that ping sound pretty often, and flashes red... Is this because the star "moved" or because PHD guiding "lost it" for a second? Or is my alignment / polar alignment so bad - it has serious trouble compensating? Or does it have to compensate "all the time" due to bad aligning?

Or ........ is it simply normal for PHD guiding to give a ping or two, then resume guiding for maybe.. 10 - 15 sec, and then ping a couple of times, and then guide a while, and ping again ... and so on and so fort?

Or is this frequent ping'ing a symptom of bad alignment or too low exposure time?

Sincerely, Alveprinsen.

[IanL]

You need to look at the status bar (lower left) to see what the error is, or check the log file.  Let us know what error is being reported.  The most usual problems are:

- Lock is being lost on the guide star.  The causes are many and various, including low SNR due to too short an exposure/wrong gain settings, poor choice of star, clouds, dew, etc., poor seeing, wind vibrations moving the scope, bad PA causing the guide star to move faster than PHD can guide out the error (though it would usually fail to calibrate in that case).

- Star being saturated due too long and exposure/wrong gain settings, too bright a star, etc.

- "Star Mass" changing too much, i.e. brightness fluctuations.  This is usually when you are marginal on SNR and one of the problems above causes the star brightness to change a lot.