Sighting (noun)

1. The act of seeing or catching sight of something.
2. A report of something seen, typically an unusual or rare occurrence.
3. The sighting of a target in aiming a weapon.

Origin:

From the verb "sight" which means to catch sight of something, from the old english "sihthian".

Examples:

1. The pilot had a sighting of the enemy plane.
2. The sighting of the rare bird was reported to the local birdwatching group.
3. The soldier adjusted the weapon's sighting before firing.
4. The UFO sighting was reported to the authorities.
5. The sighting of the comet was a once-in-a-lifetime event.