Palomar Observatory in the context of "Dark-sky movement"

65489 Ceto, as a binary also (65489) Ceto–Phorcys (provisional designation 2003 FX₁₂₈), is a binary trans-Neptunian object (TNO) discovered on March 22, 2003, by Chad A. Trujillo and Michael Brown at Palomar. It is named after the sea goddess Ceto from Greek mythology. It came to perihelion in 1989.

Quaoar (minor-planet designation: 50000 Quaoar) is a ringed dwarf planet in the Kuiper belt, a band of icy planetesimals beyond Neptune. It has a slightly ellipsoidal shape with an average diameter of 1,100 km (680 mi), about half the size of the dwarf planet Pluto. The object was discovered by American astronomers Chad Trujillo and Michael Brown at Palomar Observatory on 4 June 2002. Quaoar has a reddish surface made of crystalline water ice, tholins, and traces of frozen methane.

Quaoar has two thin rings orbiting outside its Roche limit, which defied initial theoretical expectations that rings outside the Roche limit should be unstable. Quaoar has one moon named Weywot and another unnamed moon that has not yet been confirmed. It is believed that Quaoar's elongated shape, gravitational influence of its moons, and extremely cold temperature help keep its rings stable.

Makemake (minor-planet designation: 136472 Makemake) is a dwarf planet in the Kuiper belt, a disk of icy bodies beyond the orbit of Neptune. It is the fourth largest trans-Neptunian object and the largest member of the classical Kuiper belt, having a diameter 60% that of Pluto. It was discovered on March 31, 2005 by American astronomers Michael E. ("Mike") Brown, Chad Trujillo, and David Rabinowitz at Palomar Observatory. As one of the largest objects found by this team, the discovery of Makemake contributed to the reclassification of Pluto as a dwarf planet in 2006.

Makemake is similar to Pluto with respect to its surface: it is highly reflective, covered largely by frozen methane, and stained reddish-brown by tholins. Makemake has one known satellite, which has not been named. The orbit of this satellite suggests that Makemake's rotation has a high axial tilt, which implies that it experiences extreme seasons. Makemake shows evidence of geochemical activity and cryovolcanism, which has led scientists to suspect that it might harbor a subsurface ocean of liquid water. Gaseous methane has been found on Makemake, although it is unclear whether it is contained in an atmosphere or comes from temporary outgassing.

Gonggong (minor-planet designation: 225088 Gonggong) is a dwarf planet and a member of the scattered disc beyond Neptune. It has a highly eccentric and inclined orbit during which it ranges from 33–101 astronomical units (4.9–15.1 billion kilometers; 3.1–9.4 billion miles) from the Sun. As of 2019, its distance from the Sun is 88 AU (13.2×10^ km; 8.2×10^ mi), and it is the sixth-farthest known Solar System object. According to the Deep Ecliptic Survey, Gonggong is in a 3:10 orbital resonance with Neptune, in which it completes three orbits around the Sun for every ten orbits completed by Neptune. Gonggong was discovered in July 2007 by American astronomers Megan Schwamb, Michael Brown, and David Rabinowitz at the Palomar Observatory, and the discovery was announced in January 2009.

At approximately 1,230 km (760 mi) in diameter, Gonggong is similar in size to Pluto's moon Charon, making it the fifth-largest known trans-Neptunian object (apart possibly from Charon). It may be sufficiently massive to be in hydrostatic equilibrium and therefore a dwarf planet. Gonggong's large mass makes retention of a tenuous atmosphere of methane just possible, though such an atmosphere would slowly escape into space. The object is named after Gònggōng, a Chinese water god responsible for chaos, floods and the tilt of the Earth. The name was chosen by its discoverers in 2019, when they hosted an online poll for the general public to help choose a name for the object, and the name Gonggong won.

Eris (minor-planet designation: 136199 Eris) is the most massive and second-largest known dwarf planet in the Solar System. It is a trans-Neptunian object (TNO) in the scattered disk and has a high-eccentricity orbit. Eris was discovered in January 2005 by a Palomar Observatory–based team led by Mike Brown and verified later that year. It was named in September 2006 after the Greco–Roman goddess of strife and discord. Eris is the ninth-most massive known object orbiting the Sun and the sixteenth-most massive in the Solar System (counting moons). It is also the largest known object in the Solar System that has not been visited by a spacecraft. Eris has been measured at 2,326 ± 12 kilometres (1,445 ± 7 mi) in diameter; its mass is 0.28% that of the Earth and 27% greater than that of Pluto, although Pluto is slightly larger by volume. Both Eris and Pluto have a surface area that is comparable to that of Russia or South America.

Eris has one large known moon, Dysnomia. In February 2016, Eris's distance from the Sun was 96.3 AU (14.41 billion km; 8.95 billion mi), more than three times that of Neptune or Pluto. With the exception of long-period comets, Eris and Dysnomia were the most distant known natural objects in the Solar System until the discovery of 2018 AG37 and 2018 VG18 in 2018.

The Hale Telescope is a 200-inch (5.1 m), f/3.3 reflecting telescope at the Palomar Observatory in San Diego County, California, US, named after astronomer George Ellery Hale. With funding from the Rockefeller Foundation in 1928, he orchestrated the planning, design, and construction of the observatory, but with the project ending up taking 20 years he did not live to see its commissioning. The Hale was groundbreaking for its time, with double the diameter of the second-largest telescope, and pioneered many new technologies in telescope mount design and in the design and fabrication of its large aluminum coated "honeycomb" low thermal expansion Pyrex mirror. It was completed in 1949 and is still in active use.

The Hale Telescope represented the technological limit in building large optical telescopes for over 30 years. It was the largest telescope in the world from its construction in 1949 until the Soviet BTA-6 was built in 1976, and the second largest until the construction of the Keck Observatory Keck 1 in Hawaii in 1993.

Haumea (minor-planet designation: 136108 Haumea) is a dwarf planet located beyond Neptune's orbit. It was discovered in 2004 by a team headed by Mike Brown of Caltech at the Palomar Observatory, and formally announced in 2005 by a team headed by José Luis Ortiz Moreno at the Sierra Nevada Observatory in Spain, who had discovered it that year in precovery images taken by the team in 2003. From that announcement, it received the provisional designation 2003 EL₆₁.

On 17 September 2008, it was named after Haumea, the Hawaiian goddess of childbirth and fertility, under the expectation by the International Astronomical Union (IAU) that it would prove to be a dwarf planet. Nominal estimates make it the third-largest known trans-Neptunian object, after Eris and Pluto, and approximately the size of Uranus's moon Titania. Precovery images of Haumea have been identified back to 22 March 1955.