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  • FocusCraft

FocusCraft

The FocusCraft is accessible from Tools tab
or with F6 key
 
FocusCraft is still experimental feature that should become the heart of the automatic refocusing. It detects all the stars in the frame and calculated the averaged HFD (Half Flux Diameter) and FWHM (Full Width Half Maximum).
 
Please note that star detection and the HFD / FWHM needs time and this can make the APT operation slower than you have used to!
 
Currently FocusCraft works only with images from CCD/CMOS cameras but in the next beta version will make it working for DSLR images too. So far the feedback - personal and the from the community is very positive and we have managed to clear huge amount of problems.
 
Here is example how FocusCraft looks with real data, simulating imaging session. It monitors the quality of the images and is possible to see when there is need to refocus. Pointing the graph will show the data in this moment including the focuser position if such was connected by the time of the analysis.
 
 
If the stars count is in brackets this means that the current image can't be processed. More information is printed in the Log panel. Usually once the parameters are tweaked there are no problems.
 
 
Here is how the settings dialog box looks like. It is possible to make more changes so this is the reason describe them in free form. For the next version will rework this section to look like the other parts of the User's Guide
 
 
 
Disable HFD/FWHM Calculation - this is way to disable the FocusCraft calculations. You have clear the check manually in order to enable the calculations.
 
Calculate sky brightness - FocusCraft analyzes the image to detect the brightness of the sky. This is needed to identify the stars. 
 
Use fixed sky brightness - If you want to speed the calculations you can enter fixed brightness of the sky. FocusCraft will take everything with value lower than the entered as sky. The Calculate sky brightness should be unchecked to use this value.
 
Saturation detection - values closer to 1.0 expect darker images to work. Increasing the value with give possibility to analyze brighter images. The value of 5.0 is empirically found to work fine in most of the time.
 
Star detection threshold - control how bright the stars should be in order to include them. Lower value include more stars, higher value include less. This depends on the scope and the camera. Default value is 100. If there are no stars detected in the image try to lower.
 
Min star size - defines the minimum star diameter in pixels need to be included in the analysis. The default value is 6. This parameter helps to ignore the noise without additional processing.
 
Apply noise reduction - when enabled a noise reduction will be applied on the image before the analysis. It is the most time consuming operation, so use it only when the Min star size can't help because you are using very short focal length scope/lens.
 
Reduce stars count (mid range) - takes only half of the detected stars excluding the 25% which are most faint and 25% of the most bright stars. Try enable this option if you see huge difference in the detected stars in images with same conditions.
 
Reduce stars count (high range) - takes only half (most bright) of the detected stars.  Try enable this option if you see huge difference in the detected stars in images with same conditions.