AST.ZERO_NITER

Allows AST masking to be switched off after a given number of iterations

Description:

If ast.zero_niter is non-zero, it determines the number of iterations for which the AST model should be masked. Subsequent iterations are not masked. A value of zero means " mask on all iterations" . However, if parameter "ast.zero_notlast" is set, the mask will will not be applied on the last iteration, even if ast.zero_niter is zero. This feature will probably be useful for deep point-source observations for which the large-scale noise is not as important, but keeping as much data around the edges of the map is. Note, any initial iterations specified by parameter "ast.skip" are not included in the count of iterations. If ast.zero_niter is greater than zero but less than 1.0, the AST mask will be used until the normalized change in the map between iterations drops below the ast.zero_freeze value. A negative value for ast.zero_niter will disable all masking of the AST model. If a value is set for " ast.zero_niter" , the iterative map-making process will not terminate until the number of iterations required by the supplied " ast.zero_niter" value have occurred, regardless of whether the condition specified by parameter "maptol" is achieved earlier. [0.0]
Type:
real

SMURF Usage

MAKEMAP, CALCQU