Need Advice on getting a ridiculous speeding ticket?

While driving from San Francisco down to Los Angelas I got a speeding ticket from a highway patrol man driving the opposite way on the freeway. This was in the Fresno area and when he turned around he said he caught me doing 87 in a 70 by visual radar. I asked to see the radar gun but he said that was unavailable. Is that that even possible for the officer to say he caught me doing that speed when he was driving the complete opposite way on the freeway? Also how much would a ticket like that cost?