I am pretty sure it is the AoA indexer on the nose gear. I have picture I took from vultures row, and you could clearly see the AoA indexer when the jet was in the landing attitude (see attached pic). With a long exposure you would get the affect in the picture Orion posted. I've seen similar pics of night approaches with AoA shown and discussed. That is were I got the idea for vLSO that I suggested to Serge.