stubblejumper When I got around to trying to guide, the calibration was horribly slow.
When autoguiding calibration takes a long time, check the Calibration Steps field.
Watch the movement (calibration step number and number of pixels moved) that is displayed on the screen while calibrating. You should try to adjust the Calibration Steps so that each step moves by around 2 pixels (this will complete the 25 pixels that PHD2 needs in 12 or 13 steps). If it is way off, just stop calibration, change the Calibration Steps field, and restart calibration.
If it is much slower, increase the "Calibration Steps." Likewise, decrease the Calibration Steps value if the movement is much faster than 2 pixels per step.
PHD2 needs to move the guide star by 25 pixels when calibrating (see PHD2 manual). If the Calibration Steps number is too small, it will take many steps to get to 25 pixels, and thus appears "slow."
Once you have dialed in a good value, put that down in your note book, so you can keep using this Calibration Steps value in the future when you select this particular mount. The Calibration Steps will be different each time you change the mount, or change the focal length of the guide scope, or change the guide camera, or change the guide rate of the mount.
A guide rate of 0.25x sidereal rate will require 2 times the calibration step value than 0.5x sidereal rate, for example. If the focal length of the guide scope is doubled, the Calibration Steps value need to be halved. If the pixel size of the guide camera is doubled, the Calibration Steps need to also be doubled, etc.
If you have a cheaper mount (rougher movements), you may need to use something smaller than 2 pixels per step just to get a good average of the guide scale. Likewise, if you have a premium mount, you can even use 4 or 8 pixels per step and get away with it.
Chen
