He was, however, a serious scientist, whose astronomical research won him international respect.

Astronomy relies on accurate chronometers, so astronomy-both what we would call basic astronomical research and the data tables used for surveying and navigation-advanced as timekeeping technology advanced.

By 1890 lunar photography had become a recognized branch of astronomical research.

In practice, modern astronomical research often involves a substantial amount of work in the realm(s) of theoretical and/or observational physics.

Because of the problems outlined above, this method has not been used practically for stars for several decades in astronomical research.