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We consider a free-falling observer who crosses the event horizon in theSchwarzschild background. In the course of this fall, he/she can receivesignals from an object (like a star surface) that emits radiation. We study howthe frequency received by an observer changes depending on the proper time onhis/her trajectory. The scenarios are classified depending on whether thefrequency is infinite, finite or zero near the singularity and the horizon.This depends crucially on the angular momenta of an observer and a photon. Inthis work we consider also emission process, and, as we show, conditions ofemission strongly influence parameters of a photon, and thus receivedfrequency. As one of our main results, we present numerical calculationsshowing evolution of the received frequency during the process of diving into ablack hole, depending on parameters of an observer and emitter. We also analyzehow a falling observer will see a night sky as he/she approaches thesingularity. We show that there appear several blind zones, which were notanalyzed previously.

Dynamics of redshift/blueshift during free fall under the Schwarzschild horizon