what does the second one do in general?
An astronomer is a scientist in the field of astronomy who focuses their studies on a specific question or field outside the scope of Earth.
Astronomer
An astronomer is a scientist in the field of astronomy who focuses their studies on a specific question or field outside the scope of Earth. 
which planet is saturn? It is the sixth planet from the sun. tell me one of its physical features? It is a gas giant with an average radius of about nine times that of Earth. what is this last one you mentioned? Earth is the third planet from the Sun how is the atmosphere around the former planet? The outer atmosphere of Saturn contains 96.3% molecular hydrogen and 3.25% helium by volume. which spacecraft was sent to it? The "Cassini–Huygens" space probe . which ring does it has? It has planetary rings composed mostly of water ice. where did the probe get its name from? From Giovanni Domenico Cassini and Christiaan Huygens. when was it sent to that particular thing in the space? 15 October 1997. what was the former person's profession? He was an mathematician, astronomer and engineer.
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Astronomer [SEP] Introduction
An astronomer is a scientist in the field of astronomy who focuses their studies on a specific question or field outside the scope of Earth. They observe astronomical objects such as stars, planets, moons, comets and galaxies – in either observational (by analyzing the data) or theoretical astronomy. Examples of topics or fields astronomers study include planetary science, solar astronomy, the origin or evolution of stars, or the formation of galaxies. Related but distinct subjects like physical cosmology, which studies the Universe as a whole. Astronomers usually fall under either of two main types: observational and theoretical. Observational astronomers make direct observations of celestial objects and analyze the data.