Parabolic trough, change in focal length due to cosine effect

Hello Paul,

we have a question and hope that you can help us.

With calculating a parabolic trough field,
does SAM account for the change in focal length due to
the cosine effect?
This leads to a broadening of the beam and should
get worse with thinner absorber tubes.

Kind regards,
Joe

Hello Paul,

I think there was an error in error in reasoning...

Parabolic trough basics

We thought about the issue and there is no real change
of the focal length in the parabola plane.

Kind regards,
Joe