Possible to define guide calibration location?

Voyager
1

PHD2 likes to be calibrated close to Dec 0. I know how to script a goto and then calibration, but if I’m running Robotarget, I do not think I can do this and calibration always happens at the target location. Is there a way to define a guider calibration location while using Robotarget?

Thanks
Mike

2

PHD2 will complain about a calibration more than 20 degrees away from Dec 0, but if you have Voyager configured to calibrate on sequence start, it will work just fine despite the warning.

I used to calibrate near the equator and keep the calibration for ages but calibrating at the target declination should be more accurate (As you are calibrating for the actual declination, not calibrating near Dec 0 and PHD2 calculating the changed parameters to suit the target dec) and if you set the calibration exposure to 1 second it is quite fast anyway at the start of each target.

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3

can you please expand on the comment that PHD2 is more accurate if you recalibrate for each target? I have always recalibrate only when there was a physical modification to the system

4

When you calibrate at once declination and then point elsewhere, PHD2 is calculating the change in the guiding rates to match the new declination. Depending on where you calibrate and where you then point, any calibration issues can be magnified. If you calibrate at the target declination that is eliminated.

It is not going to degrade guiding, takes a short time, and if you happened to make a mistake and cause PHD2 to decide to recalibrate, will save your sequence from erroring out as sequence guide start will time out before a calibration is done (Been there once)

5

Because what you are doing is something that presume your setup is perfect, perfectly balanced and in a real sphere without mechanical and orthogonal problems and not affected by friction, temperature change, differential flexure.

Calibration on target before guiding is the method to achieve the best performance.

Said this you can calibrate once and forget in 99.9% of cases, PHD2 PID algoritm will working for you , just the RMS will be affected.

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