PHD2 Calibration Issue

Hi Community.
I’m using Voyager with a 10" Newton scope on a 10Micron GM2000 HPS mount.
Guide is carried out through an OAG and a ZWO ASI 120 MM.
Now I’m experiencing an issue resulting from a “star lost” error during PHD2 calibration.
In particular the calibration procedure always fails to complete while using the “Voyager Roboguide” setting. On the contrary it works perfectly when the “Native Guide Control” is set.
I would like to know what’s the difference of the two settings so to understand better what could be the possible source of the problem.
Thank you in advance!

Star lost coming from PHD2, this mean PHD2 doesn’t like parameters you choose on VOyager RoboGuide setup or when you try to calibrate sky is not in best conditions.

Check your setting on RoboGuide setup (? to low value on saturation parameter) or if PHD2 setup (on brain button) have some parameters modified that fight against RoboGuide).

Difference is with RoboGuide the AI of Voyager choose a guide star for you , with native … PHD2 do it for you.

Its useful if you take your time to think on what you change.

All the best

Leo’s comments point out the most likely problem.

When you calibrate in PHD2, is the mount pointing at exactly the same spot as when you calibrate from Voyager? Especially with an OAG, there are some areas with guide stars and others with none.

Watch PHD2 while it is trying to calibrate from Voyager and see what star it is picking and whether that is a good star to use.

I would suggest to also look at the Exposure length and Binning settings in the Voyager Sequence definition, Guiding panel. These are the values that will be used for Calibration when started from Voyager - make sure they are high enough to get a good star for calibration in PHD2. OAG’s can be especially tricky to find a good calibration star.

Also check your error retry count in Setup -> Guiding. Sometimes calibration will fail one time but work the next - so use a retry setting high enough to have it try a few times.

On the “Brain” menu in PHD2, I find setting the Search Region (on the Guiding tab) a little bigger can help reduce the lost star problem while calibrating.

1 Like