Tips for AO Operation

This section includes various tips and techniques for optimizing your AO experience.


Before you Start


Focal Length and Resolution

The primary purpose of the AO unit is to optimize resolution, which typically means it is used on long focal length / high resolution imaging systems.  Optimizing resolution is achieved by:

AO is particularly effective in good seeing conditions at high resolution. In some cases it can improve the FWHM of your stars by 20% to 30%.


When to Use Binning


When to Calibrate AO

AO Calibration needs to be done:

Once the unit is calibrated, it never needs to be calibrated again unless you somehow mechanically change the hardware, e.g. rotate the AO with respect to the camera, change camera, change spacing to the camera, etc.


When to Calibrate Drive

First of all, if your mount tracks accurately enough that the tip/tilt never runs out of range, you don't even need to enable the mount controls.  If you have slow drift or large periodic error, then you will want to enable mount bumping.  The purpose of the bumping is to make sure the guide star never drifts to the point where the AO hits the end stop.  It does not need to - and usually will not - move the AO back to center.  It simply needs to avoid hitting the end stops.  

You need to calibrate the drive:


Watch Out For Guide Cables

Unfortunately the "ST-4" style tracking interface cable is a somewhat loosely-defined standard. RJ-12 connectors can be flipped in two possible orientations. Some mount and camera manufacturers use the "wrong" orientation, so the cable that came with the autoguider camera may not work with your mount.  If the cable is flipped, a common result is that the mount continuously moves in declination; sometimes it will move only on one axis.  

In addition these cables are relatively fragile and can be easily damaged.

It is generally safer and easier to use the ASCOM PulseGuide or Telescope option if available (Control Via under the Guide Tab).


Tips for Calibration (AO and Drive)


Update Rate

The update rate is measured in cycles per second, or Hertz (Hz).