In 1918 he used Cepheid variables to estimate the size of the Milky Way. The Shapley Supercluster of galaxies is named after him as well.
That's a really hard one to answer. If you are talking about historical or "famous" figures in astronomy, it would depend on the list provided. If you are talking about who made the latest contribution in general, well there are tons of papers constantly being published, so it will change frequently.
Astronomy
There is a branch of astronomy called planetary astronomy that takes geology and uses it to examine other planets, so yes rocks are studied in astronomy.
Rizal Technological University in Mandaluyong City is the first and currently the only school that offers courses in astronomy such as B.S. Astronomy Technology and MS in Astronomy
As one of the sciences astronomy is most closely related to mathematics, physics and chemistry.
chupz
The Great contribution to astronomy from ancient Egypt was the Almagest.
Hubble
astronomy space telescope
The German Johannes Kepler and his laws of planetary motion is an important contribution to science and astronomy
Math & astronomy.
He showed that the planets traveled in elliptical orbits
She is best remembered for her astronomy column, which ran from 1951 until 1981.
The largest contribution from the Babylons was the introduction of Math and Astronomy. The Babylons numerical system helped create the 360 degree system.
She discovered astronomy which led to future inventions
Newton invented the reflector telescope in the 1680's.
They did create astronomy which is kinda of a scientific contribution and an impact on the ecosystem.