6398 Timhunter, provisional designation 1991 CD, is a stony Phocaea asteroid from the inner regions of the asteroid belt, approximately 5.5 kilometers in diameter.
 It was discovered on 10 February 1991, by American astronomer couple Carolyn and Eugene Shoemaker, in collaboration with Canadian astronomer David H. Levy at Palomar Observatory in California, United States.
 It was named for American amateur astronomer Tim Hunter.
2003 Harding, provisional designation 6559 P-L, is a carbonaceous Eoan asteroid from the outer regions of the asteroid belt, approximately 18 kilometers in diameter.
 It was discovered during the Palomar–Leiden survey on 24 September 1960, by astronomers Ingrid and Cornelis van Houten at Leiden, and Tom Gehrels at Palomar, California.
 The asteroid was later named after astronomer Karl Ludwig Harding.
Edwin Powell Hubble (November 20, 1889 – September 28, 1953) was an American astronomer.
 He played a crucial role in establishing the fields of extragalactic astronomy and observational cosmology and is regarded as one of the most important astronomers of all time.
3936 Elst, provisional designation 2321 T-3, is a stony Vestian asteroid from the inner regions of the asteroid belt, approximately 5 kilometers in diameter.
 The asteroid was discovered on 16 October 1977, by Dutch astronomer couple Ingrid and Cornelis van Houten at Leiden, on photographic plates taken by Dutch–American astronomer Tom Gehrels at Palomar Observatory in California, United States.
 It was named after Belgian astronomer Eric W. Elst.
4065 Meinel, provisional designation 2820 P-L, is an asteroid from the inner regions of the asteroid belt, approximately 4 kilometers in diameter.
 It was discovered on 24 September 1960, by Dutch astronomer couple Ingrid and Cornelis van Houten on photographic plates taken by Dutch–American astronomer Tom Gehrels at Palomar Observatory, California.
 The asteroid was named for American astronomer Aden Meinel.
5040 Rabinowitz, provisional designation 1972 RF, is a stony Phocaea asteroid from the inner regions of the asteroid belt, approximately 6 kilometers in diameter.
 It was discovered by Dutch–American astronomer Tom Gehrels at Palomar Observatory on 15 September 1972.
 Contrary to most of his discoveries, this asteroid is unrelated to the Palomar–Leiden survey and exclusively credited to Tom Gehrels.
(99907) 1989 VA is a very eccentric, stony asteroid and near-Earth object, approximately 1 kilometer in diameter.
 It was discovered on 2 November 1989, by American astronomer couple Carolyn and Eugene Shoemaker and Canadian astronomer David Levy at the Palomar Observatory on Mount Palomar, California.
Palomar 4 is a globular cluster of the Milky Way galaxy.
 It was discovered in 1949 by Edwin Hubble and again in 1955 by A. G. Wilson.
 It is 356,000 light-years away.
1965 van de Kamp, provisional designation 2521 P-L, is a stony asteroid from the central region of the asteroid belt, approximately 12 kilometers in diameter.
 It was discovered on 24 September 1960, by Dutch astronomer couple Ingrid and Cornelis van Houten at Leiden Observatory, on photographic plates taken by Dutch–American astronomer Tom Gehrels at the U.S Palomar Observatory, California.
 It was later named after Dutch astronomer Peter van de Kamp.
iPTF 14atg is a type-Ia supernova discovered on 3 May 2015.
 The supernova is located in galaxy IC 831, some 300 Mly distant.
 The supernova is thought to have ignited on May 2 or 3.
 The supernova's shockwave slammed into a companion star, shocking it into producing an ultraviolet pulse.
 The companion star that was hit is suspected to be a red giant star.
 This detection of the UV signal represents the first time the collision event of a supernova shockwave upon a companion star has been detected.
 The supernova was discovered by the Intermediate Palomar Transient Factory (iPTF), a successor to the earlier Palomar Transient Factory, and based at the Palomar Observatory in California.
 The data was processed by collaborators in Europe, that lead to the supernova discovery.

Question: Palomar 4 was discovered by the astronomer of what nationality?
Answer: American