long Tom

noun3

1. •
   (historical) Any of various early cannon and field guns.
2. •
   A high-powered lens for long-distance filming or photography.

   • Digging around second-hand shops you may come across an old newspaper or picture agency 'Long Tom' lens. — 1976
3. •
   A device formerly used in California for washing gold from the earth or mineral spoil with which it is excavated. It is a sloping wooden trough which widens at the lower end.