effective_focal_length

Telescope: LSTN-01

Description: Due to asymmetric image aberrations, in particular for single-reflector telescope, segmented or not, the inverse image ‘plate scale’ or, more precisely, the ratio of off-center distance in the focal plane (projection for curved focal surface) to the tangent of the off-axis angle, does not match the nominal focal plane very well. This effective value here should be better suitable for shower reconstruction than the nominal focal length and is supposed to be based on ray-tracing simulations of point sources, at distances typical of showers and imaged onto the actual focal surface at the level of the pixel entrances. Non-zero values will be reported as-is in the output data and may be used for the built-in reconstruction in sim_telarray. If no value is given, sim_telarray may estimate a value, based on optics type and f/D ratio, for its internal purpose but will not report such an estimate in the output data. Due to subtle effects of image cleaning (and thus image intensity) on cutting off parts of the asymmetric point-spread function, analysis programs should use this value or, if not available, an estimate of it only as a starting point and evaluate the actual analysis specific and perhaps image intensity and NSB dependent real effective focal length by itself.

Model Version	Value
5.0.0	[2923.7 0. 0. 0. 0. ] cm
6.0.0	[2923.7 0. 0. 0. 0. ] cm