What tool do most modern astronomers NOT use directly anymore?

Because the speed of light is constant in all reference frames, the au will no longer change depending on an observer's location in the Solar System. Redefining the au has been possible for decades — modern astronomers can use spacecraft, radars and lasers to make direct measurements of distance.

Show him another sport or something

Amethod of procedure that has characterized natural science since the 17th century, consisting in systematic observation, measurement, and experiment, and the formulation, testing, and modification of hypotheses.