FocusMax V5 is the the premier auto-focusing software solution for thousands of professional and amateur astronomer’s worldwide! It is routinely used for automated asteroid and supernova searches, minor planet astrometry, variable star photometry, deep sky imaging, and more. Version 5 adds new features and capabilities to this already widely-accepted automatic focusing standard.

What's New in Version 5


  • Multi-Star Focus utilizes many stars in the field allowing the astronomer to autofocus the telescope on the current imaging field without having to slew away to center a focus star. If there are an insufficient number of stars, then AcquireStar may be enabled by the user to slew the telescope to a target field containing stars in a desired magnitude range for the selected filter
  • A new proprietary star detection algorithm which identifies the brightest stars in the field then determine the best stars to be used for the autofocus run while rejecting double stars, galaxies and nebulosity that may be in the field. The star detection algorithm will also identify severely out-of-focus stars!
  • Focus time has been optimized and is approximately 30% faster than FocusMax V4
  • Target and Focus binning may now be specified for each filter which will benefit users with narrow band filters
  • A new algorithm has been developed to identify suspect data during a focus run and automatically re-sample, statistically test and then eliminate suspect data yielding improved focus accuracy
  • An improved Focus Convergence algorithm has been implemented which will sample the focus star until the focus position has been determined based on current seeing conditions
  • Additional focus binning of 3×3 and 4×4 has been added which will be useful with small pixel CMOS cameras and users with narrow band filters.

Artificial Intelligence (A.I.)

  • A.I. has been implemented that begin to optimize various user settings based on historical data.


  • A new algorithm that will allow the focuser to be positioned in the non-linear portion of the Vcurve during an autofocus run resulting in higher star S/N allowing the use of dimmer stars resulting in improved final focus quality
  • A new algorithm has been implemented to fit Vcurve data to determine Vcurve slopes and PID
  • A new outlier detection method has been developed to measure Vcurve fit and automatically reject suspect data points
  • A new method has implemented to determine if the Vcurve shape is suspect with a poorly defined ‘V’
  • An ‘Optimize’ button has been added in the Profile Window to identify potential suspect Vcurve slopes and PID from Vcurve runs
  • A new Vcurve Window containing a detailed graph of the Vcurve with mouse-over data display
  • Vcurve data collected with FocusMax V4 may imported into FocusMax V5 to realize the above improvements.


  • AcquireStar Wizard will determine the optimum star magnitude to achieve the user defined target flux with a 1 sec exposure
  • FilterOffset Wizard will measure the difference in steps between a target and a reference filter. It is designed to allow the user to collect offset data for each filter over many runs (nights) then optimized the data to identify outliers.

Multi-Star Focus

Selecting Multi-Star Focus will allow you to focus on-field and not have to slew away from the current target. Stars that are too bright or too dim will be excluded the focus routine. 

Stars are identified using a proprietary algorithm that will identify severely out-of-focus stars in the field. In the image below, 28 stars were identified with a Mean Field HFD = 24.56.

 The total focus time was 93 sec!

See the Videos Below for More Detail