A newly developed analytical optical approach—first-principle OPTical intercept calculation (FirstOPTIC)—is employed to study the optical impact of receiver position error on parabolic trough collectors. The FirstOPTIC method treats optical error sources the way they are typically characterized in laboratory measurements using a geometrical or optical interpretation. By analyzing a large number of cases with varying system parameters, such as overall system optical error and the collector's geometrical parameters, a practical correlation between actual measurement data and its corresponding error-convolution approximation for receiver position error is established from parametric study; the correlation enables a direct comparison of receiver position error to the sun shape and other optical error sources (such as mirror specularity and slope error) with respect to the collector optical performance. The effective coefficients that define the correlation of actual measurement data and its error-convolution approximation for receiver position error are also summarized for several existing trough collectors; these make it convenient to characterize the relative impact of receiver position error compared with other optical error sources, which was not straightforward in the past. It is shown that FirstOPTIC is a suitable tool for in-depth optical analysis and fast collector design optimization, which otherwise require computationally intensive ray-tracing simulations.