iKarus StellarMate X - Page 66

The StellarMate X Manual
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for instance the Bahtinov edge detection.
· Sigma : This is the gaussian blur sigma value. Used for blurring the image before for
instance the Bahtinov edge detection.
· Algorithm : Select the autofocus process algorithm:
o Iterative : Moves focuser by discreet steps initially decided by the step size.
Once a curve slope is calculated, further step sizes are calculated to reach
optimal solution. The algorithm stops when the measured HFR is within
percentage tolerance of the minimum HFR recorded in the procedure.
o Polynomial : Starts with iterative method. Upon crossing to the other side of the
V-Curve, polynomial fitting coefficients along with possible minimum solution are
calculated. This algorithm can be faster than purely iterative approach given a
good data set.
o Linear : Samples focus inward in a regular fashion, using 2 passes. The
algorithm can be slow, but it is more resilient to backlash. Start with the focuser
positioned near good focus. Set Initial Step Size and Max Travel for the desired
sampling interval and range around start focus position. Tolerance should be
around 5%.
· Tolerance : The tolerance percentage values decides when the autofocus process
stops in the Iterative algorithm. During the autofocus process, HFR values are
recorded, and once the focuser is close to optimal position, it starts measuring HFRs
against the minimum recorded HFR in the sessions and stops whenever a measured
HFR value is within % difference of the minimum recorded HFR. Decrease value to
narrow optimal focus point solution radius. Increase to expand dsolution radius.
Caution
Setting the value too low might result in repetitive loop and would most likely
result in a failed autofocus process.
· Average over : Sets the number of frames to capture in order to average the HFR value
at the current focuser position.
· Num. of rows : The number of rows set in this field will be combined in the Bahtinov
max average calculation. Changing this value might help to match the Bahtinov lines on
the star pattern more accurately.
Mechanics