It is important to the BPCR shooter that we set our spotting scope to read these mirage heat waves by focusing on the target and backing off 1/8 to 1/4 of a turn, counter-clockwise, so we are slightly out of focus with the target but can still clearly see the mirage heat waves that are present.e have all seen mirage while driving on a hot day in the form of the heat waves coming off of a black-topped road. Wind moves these waves the harder the wind is blowing the faster the waves (mirage) will move.