[O.B.Left]

Why do u think that because he is on the elbow plane he does not see a straight line also what's this about Doppler I don't believe it.

I know squat about doppler but I don't think the readings could be wrong. Maybe the interpretation of things could get out of whack but not the data... assuming its properly collected , calibrated etc .

The only way to see the straight line club head blur is to plane the club head to a super high plane. Homer said " now its a vertical plane angle , well almost vertical". Arnie had a pretty high plane angle but not that high. He also looks to be planing his shaft for the most part. And so it makes me wonder what blur he would see assuming he noticed the blur. Its only an option for monitoring club travel its not an imperative or anything. Id bet on some sort of cross line aiming point , right arm throw deal if you put a gun to my head on Arnies monitoring . Which you probably wouldnt mind doing right now I suspect. You and a whole bunch of other people .