Plate.MaxMatchResidual Property

Plate.MaxMatchResidual (read-write, Double)

[advanced] The maximum positional error (arc-seconds) for matching image and catalog stars (0.0 = auto, 1.0 pixel equiv.)

Syntax

Plate.MaxMatchResidual [= Double]

The property syntax has these parts:

Part	Description
Value (Double)	[advanced] The maximum positional error (arc-seconds) for matching image and catalog stars (0.0 = auto, 1.0 pixel equiv.)

Remarks

This is an advanced property. In most cases, you will not need to change this value, the default will work. If you are having trouble getting plate solving to work, first verify the accuracy of ArcsecPerPixelHoriz and ArcsecPerPixelVert.

If you need very accurate matching, and you are using an accurate catalog (such as Tycho-2) you can try reducing this value from the automatic value (which is calculated to be equivalent to 1.0 pixel). Fewer stars will match, but the match average residual may reduce and give you a more accurate position. On the other hand, the number of stars may reduce so far that the solution degrades while the residuals appear to get better! In the limit, solution will fail if you make it too tough.

This property is automatically recalculated henever a new image is attached, or when ArcsecondsPerPixelHoriz or ArcsecondsPerPixelVert are changed. To ensure that you don't get the rug pulled out from under you, change this property just before you call Solve().

Legal values range from 0.0 through 20.0. A 20 arcsecond fit is really poor!