sighter

plural sighters

1. One who has sighted or seen something.

   He would have been a great help in the task of examning the reports submitted and interviewing the sighters.

   1965, James Holledge, Flying Saucers Over Australia, Sydney: Horwitz Publications, page 52

2. A targeteer.
3. A trial shot in rifle, artillery shooting, or sports like football, to set the range, targeting etc.

   Kane looked in the mood, testing the goalkeeper, Hannes Thor Halldórsson, with an early sighter and then being denied what appeared to be a good goal on six minutes by an offside flag.

   2020 September 5, David Hytner, “Raheem Sterling keeps his cool to see off Iceland amid blaze of late drama”, in The Guardian

4. A sight on a weapon.