  TIPTOP is a python library that is able to quickly compute Point Spread
Functions (PSF) of any kind of Adaptive Optics systems. This library has
multiple objectives: support the exposure time calculators of future VLT and
ELT instruments, support adaptive optics systems design activities, be part of
PSF reconstruction pipelines and support the selection of the best asterism of
natural guide stars for observation preparation. Here we report one of the last
improvements of TIPTOP: the introduction of the error given by a single
conjugated laser, commonly known as the cone effect. The Cone effect was not
introduced before because it is challenging due to the non-stationarity of the
phase. Laser guide stars are at a finite distance with respect to the telescope
and probe beam accepted by the wavefront sensor has the shape of a cone. Given
a single spatial frequency in an atmospheric layer, the cone effect arises from
the apparent magnification or stretching of this frequency when it reaches the
wavefront sensor. The magnification effect leads to an incorrect estimation of
the spatial frequency. Therefore, we estimate the residual power by calculating
the difference between two sinusoids with different periods: the nominal one
and the magnified one. Replicating this for each spatial frequency we obtain
the power spectrum associated with the cone effect. We compare this estimation
with the one given by end-to-end simulation and we present how we plan to
validate this with on-sky data.
