Actual Step

Manual Focus Main Camera on ASIAIR Pro

updated: 2023-07-01

Purpose

Finding the correct focuser setting for best images

Previous Step

Next Step

Required Equipment

Telescope

any

Reducer

any

Filter or Mask

Bhatinov Mask (recommended!)

Camera

ZWO ASI294

Focuser

ZWO EAF

Session Control

ASIAIR App

Procedure:

General focuser settings are accessible from the Focuser Tab.


When entering the Auto Focus settings,  you can set the AF step size, define time, temperature and/or Filter wheel triggers to initiate a refocusing during an Autorun sequence.



NOTE: as per above, user defined backlash is not used by AF routines.


You can manually start the auto focus  by clicking on the AF sign in the left menu focus tool:



or enforce auto focusing in case of:

  • time trigger (every hour or so)
  • temperature change (e.g. every 1°C temperature change)
  • Filter change (recommended)
  • before starting a new object  (recommended)
  • after a Meridian flip (highly recommended!)


Auto focus Procedure

Once you manually reached an appropriate focus, a typical AF sequence will move EAF five times (x5) the EAF Step Size then decrease back measuring FHD of selected star at each iteration building the focusing V-curve.


Once focus point is estimated, a final verification sequence, similar to the first one, but jump is one and half time the EAF Step Size, iterating down by half EAF Step Size.


NOTE: If your original manual focus starting point does not allow AF to successfully draft a V-curve and estimate a focus position, the routine will jump further in EAF position to resume another attempt (as seen below).




Example given with default 30 step:


Reference:  see this article 

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