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