Yes, STROBOSCOPES is a Scrabble word!

Letter values in Scrabble US: S 1, T 1, R 1, O 1, B 3, O 1, S 1, C 3, O 1, P 3, E 1, S 1.

Is it a valid word?

STROBOSCOPES is a valid word in the official Scrabble dictionary (US), the UK Scrabble Dictionary and Words with Friends (ENABLE).

scientific instrument that provides a flashing light synchronized with the periodic movement of an object; can make moving object appear stationary

Also: strobe light.