Index
Preserving Pointing Accuracy
Pointing accuracy refers to how accurately the mount can point to a target in the sky, given its RA Dec coordinates. Pointing accuracy determines how accurately mount can perform GOTO, alt-azimuth mount tracking or identifying an object. To have good pointing accuracy, build a good pointing model by performing [Alignment] then [Sync].
For pointing model to stay valid, three things need to stay the same. Specifically, at pointing time, these three things need to be the way they were at alignment time. The next sections explain what they are and, if they were lost, how to recover them.
Mount Physical Orientation
- This refers to orientation of mount chassis relative to the ground plus the geographical location of the mount.
- To avoid losing mount physical orientation by an accidental bump, anchor the mount tripod well or use a permanent pier.
Axis Position Origin
- More specifically, this refers to the position of the axis relative to the chassis when the axis reading is zero.
- It is lost when mount is powered off, or when the clutch is released while the [auxiliary encoder] is off.
- It loses precision whenever auxiliary encoder is turned on.
- Use [Auto Home] to restore axis position origin on supported mounts.
- A way to avoid losing axis position origin if the mount has to be powered off, is to perform [Hibernate] before powering the mount off, then not moving the mount before reconnecting app with mount.
Time And Location Setting
- This refers to the location setting in the app and the system time of the device running the app. Same system time means the system time has not been adjusted.
- To recover:
- Location: You do not need to do anything because when pointing model is loaded, its associated location is also loaded. This has the side effect that if you set location before loading pointing model, what you entered will be overwritten.
- Time: It is good practice to keep the system time synced with network time on all devices running app. That way, if pointing model moves between devices during [PM (Pointing Model) Sharing], there would not be a time discrepancy.