A frustrating night (July 17 / 18) for visual observers. Observing from 23:00UT. Comet is buried in low cloud and haze to the north and at times only the nucleus is seen naked eye. It does not improve as the comet rises. In 10x50B the first 2 degrees of the tail is seen and for a few fleeting seconds the tail extends to at least 5 degrees but then it disappears. It seems that these first couple of degrees are much brighter that the remainder. All this is most disappointing as I got the impression that in a clear sky the comet would be looking superb. When visible the tail is very broad with much detail. The tail tonight is a very good example of the benefits of averted vision, often 5 degrees seen with AV and zero with DV.