  A computer program is introduced, which allows to determine statistically
optimal approxi-mation using the "Asymptotic Parabola" fit, or, in other words,
the spline consisting of polynomials of order 1,2,1, or two lines
("asymptotes") connected with a parabola. The function itself and its
derivative is continuous. There are 5 parameters: two points, where a line
switches to a parabola and vice versa, the slopes of the line and the curvature
of the parabola. Extreme cases are either the parabola without lines (i.e.the
parabola of width of the whole interval), or lines without a parabola (zero
width of the parabola), or "line+parabola" without a second line. Such an
approximation is especially effective for pulsating variables, for which the
slopes of the ascending and descending branches are generally different, so the
maxima and minima have asymmetric shapes. The method was initially introduced
by Marsakova and Andronov (1996OAP.....9..127M) and realized as a computer
program written in QBasic under DOS. It was used for dozens of variable stars,
particularly, for the catalogs of the individual characteristics of pulsations
of the Mira (1998OAP....11...79M) and semi-regular (200OAP....13..116C)
pulsating variables. For the eclipsing variables with nearly symmetric shapes
of the minima, we use a "symmetric" version of the "Asymptotic parabola". Here
we introduce a Windows-based program, which does not have DOS limitation for
the memory (number of observations) and screen resolution. The program has an
user-friendly interface and is illustrated by an application to the test signal
and to the pulsating variable AC Her.
