The Window Sill Observatory

Dave’s Focus Meter (DFM)

Dave’s Focus Meter gives you a visual indication of just how sharp your current video screen or image is. It will work with any video source, live or recorded, and any image format. It is designed for astronomy, microscopy, security and any area where precise focus is important.

It also has built-in support for ASCOM focusers with an autofocus feature that will turn your telescope into a giant autofocus lens.

Current features include:

  • Single application covers Windows XP, Vista, 7 (both 32 and 64 bit versions).
  • Multiple focus analysis methods to suit different subjects.
  • Can monitor focus of point sources (stars) or surface features (craters, sunspots, planets, prominences, cells).
  • Cancellation of image shift induced by optical train during focussing.
  • Focus meter results displayed in raw instantaneous and smoothed modes.
  • Real time graphs of focus history.
  • User selectable area to meter focus on.
  • Full control of ASCOM motorised focusers – relative and absolute types.
  • ASCOM In and Out buttons.
  • ASCOM user-settable position presets.
  • ASCOM autofocus routine.
  • Multi-processor support with user defined cores to use
  • Settings manager allows different profiles to be saved for different equipment and targets.

A selection of screenshots are below.



  1. From the features list, this looks like a “Must Have” piece of software. Looking forward to trying it out!

    Comment by Jeff Seivert — February 27, 2012 @ 3:06 pm

    • Thanks Jeff – it is taking longer than I estimated to get it released. I should have added the ASCOM support as an upgrade. Still, hindsight is always 20:20.

      Comment by Dave — February 28, 2012 @ 3:49 pm

  2. Hi Dave, this looks like a useful program for CCTV focus on a laptop any chance in getting a test version

    Comment by Steven — March 6, 2013 @ 9:04 pm

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