Palomar Observatory

Last updated
Palomar Mountain Observatory
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Alternative names675 PA OOjs UI icon edit-ltr-progressive.svg
Organization
Observatory code 675   OOjs UI icon edit-ltr-progressive.svg
Location San Diego County, California
Coordinates 33°21′23″N116°51′54″W / 33.3564°N 116.865°W / 33.3564; -116.865
Altitude1,712 m (5,617 ft) OOjs UI icon edit-ltr-progressive.svg
Established1928  OOjs UI icon edit-ltr-progressive.svg
Website www.astro.caltech.edu/palomar/ OOjs UI icon edit-ltr-progressive.svg
Telescopes
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Location of Palomar Observatory
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Palomar Observatory is an astronomical research observatory in San Diego County, California, United States, in the Palomar Mountain Range. It is owned and operated by the California Institute of Technology (Caltech). Research time at the observatory is granted to Caltech and its research partners, which include the Jet Propulsion Laboratory (JPL), Yale University, [1] and the National Astronomical Observatories of China. [2]

Contents

The observatory operates several telescopes, including the 200-inch (5.1 m) Hale Telescope, [3] the 48-inch (1.2 m) Samuel Oschin Telescope [4] (dedicated to the Zwicky Transient Facility, ZTF [5] ), the Palomar 60-inch (1.5 m) Telescope, [6] and the 30 cm (12 in) Gattini-IR [7] telescope. Decommissioned instruments include the Palomar Testbed Interferometer and the first telescopes at the observatory, an 18-inch (46 cm) Schmidt camera from 1936.

History

Palomar Mountain Observatory featured on 1948 United States stamp Palomar Mountain Observatory 3c 1948 issue U.S. stamp.jpg
Palomar Mountain Observatory featured on 1948 United States stamp

Hale's vision for large telescopes and Palomar Observatory

Astronomer George Ellery Hale, whose vision created the Palomar Observatory, built the world's largest telescope four times in succession. [8] He published a 1928 article proposing what was to become the 200-inch Palomar reflector; it was an invitation to the American public to learn about how large telescopes could help answer questions relating to the fundamental nature of the universe. Hale followed this article with a letter to the International Education Board (later absorbed into the General Education Board) of the Rockefeller Foundation dated April 16, 1928 in which he requested funding for this project. In his letter, Hale stated:

"No method of advancing science is so productive as the development of new and more powerful instruments and methods of research. A larger telescope would not only furnish the necessary gain in light space-penetration and photographic resolving power, but permit the application of ideas and devices derived chiefly from the recent fundamental advances in physics and chemistry."

Hale Telescope

The 200-inch telescope is named after astronomer and telescope builder George Ellery Hale. It was built by Caltech with a $6 million grant from the Rockefeller Foundation, using a Pyrex blank manufactured by Corning Glass Works under the direction of George McCauley. Dr. J.A. Anderson was the initial project manager, assigned in the early 1930s. [9] The telescope (the largest in the world at that time) saw first light January 26, 1949 targeting NGC 2261. [10] The American astronomer Edwin Powell Hubble was the first astronomer to use the telescope.

The 200-inch telescope was the largest telescope in the world from 1949 until 1975, when the Russian BTA-6 telescope saw first light. Astronomers using the Hale Telescope have discovered distant objects called quasars (a subset of what was to become known as Active Galactic Nuclei) at cosmological distances. They have studied the chemistry of stellar populations, leading to an understanding of the stellar nucleosynthesis as to origin of elements in the universe in their observed abundances, and have discovered thousands of asteroids. A one-tenth-scale engineering model of the telescope at Corning Community College in Corning, New York, home of the Corning Glass Works (now Corning Incorporated), was used to discover at least one minor planet, 34419 Corning.

Architecture and design

Hale Telescope Dome Palomar Observatory Dome - High Resolution.jpg
Hale Telescope Dome

Russell W. Porter developed the Art Deco architecture of the Observatory's buildings, including the dome of the 200-inch Hale Telescope. Porter was also responsible for much of the technical design of the Hale Telescope and Schmidt Cameras, producing a series of cross-section engineering drawings. Porter worked on the designs in collaboration with many engineers and Caltech committee members. [11] [12] [13]

Max Mason directed the construction and Theodore von Karman was involved in the engineering.

Directors

Palomar Observatory and light pollution

Much of the surrounding region of Southern California has adopted shielded lighting to reduce the light pollution that would potentially affect the observatory. [14]

Telescopes and instruments

Hale telescope dome Palomar Observatory.jpg
Hale telescope dome
Component of the Hale telescope Palomar Observatory 2012 09.jpg
Component of the Hale telescope

Decommissioned instruments

Research

The now decommissioned 18-inch Schmidt Camera 18 Inch Schmidt Camera at Palomar Observatory.jpg
The now decommissioned 18-inch Schmidt Camera

Palomar Observatory remains an active research facility, operating multiple telescopes every clear night, and supporting a large international community of astronomers who study a broad range of research topics.

The Hale Telescope [3] remains in active research use and operates with a diverse instrument suite of optical and near-infrared spectrometers and imaging cameras at multiple foci. The Hale also operates with a multi-stage, high-order adaptive optics system to provide diffraction-limited imaging in the near-infrared. Key historical science results with the Hale include cosmological measurement of Hubble Flow, the discovery of quasars as the precursor of Active Galactic Nuclei, and studies of stellar populations and stellar nucleosynthesis.

The Oschin and 60-inch telescopes operate robotically and together are support a major transient astronomy program, the Zwicky Transient Facility.

The Oschin was created to facilitate astronomical reconnaissance, and has been used in many notable astronomical surveys—among them are:

POSS-I

The initial Palomar Observatory Sky Survey (POSS or POSS-I), sponsored by the National Geographic Institute, was completed in 1958. The first plates were exposed in November 1948 and the last in April 1958. This survey was performed using 14 inch2 (6 degree 2) blue-sensitive (Kodak 103a-O) and red-sensitive (Kodak 103a-E) photographic plates on the Oschin Telescope. The survey covered the sky from a declination of +90 degrees (celestial north pole) to −27 degrees and all right ascensions and had a sensitivity to +22 magnitudes (about 1 million times fainter than the limit of human vision). A southern extension extending the sky coverage of the POSS to −33 degrees declination was shot in 1957–1958. The final POSS I dataset consisted of 937 plate pairs.

Digitized Sky Survey (DSS) produced images which were based on the photographic data developed in the course of POSS-I. [24]

J.B. Whiteoak, an Australian radio astronomer, used the same instrument to extend POSS-I data south to −42 deg declination. Whiteoak's observations used using the same field centers as the corresponding northern declination zones. Unlike POSS-I, the Whiteoak extension consisted only of red-sensitive (Kodak 103a-E) photographic plates.

POSS-II

The Second Palomar Observatory Sky Survey (POSS II, sometimes Second Palomar Sky Survey) was performed in the 1980s and 1990s and made use of better, faster films and an upgraded telescope. The Oschin Schmidt was upgraded with an achromatic corrector and provisions for autoguiding. Images were recorded in three wavelengths: blue (IIIaJ. 480 nm), red (IIIaF, 650 nm) and near infrared (IVN, 850 nm) plates, respectively. Observers on POSS II included C. Brewer, D. Griffiths, W. McKinley, J. Dave Mendenhall, K. Rykoski, Jeffrey L. Phinney and Jean Mueller (who discovered over 100 supernovae by comparing the POSS I and POSS II plates). Mueller also discovered several comets and minor planets during the course of POSS II, and the bright Comet Wilson 1986 was discovered by then graduate student C. Wilson early in the survey. [25]

Until the completion of the Two Micron All Sky Survey (2MASS), POSS II was the most extensive wide-field sky survey. When completed, the Sloan Digital Sky Survey will surpass POSS I and POSS II in depth, although the POSS covers almost 2.5 times more area on the sky.

POSS II also exists in digitized form (i.e., the photographic plates were scanned) as part of the Digitized Sky Survey (DSS). [26]

QUEST

The multi-year POSS projects were followed by the Palomar Quasar Equatorial Survey Team (QUEST) Variability survey. [27] This survey yielded results that were used by several projects, including the Near-Earth Asteroid Tracking project. Another program that used the QUEST results discovered 90377 Sedna on 14 November 2003, and around 40 Kuiper belt objects. Other programs that share the camera are Shri Kulkarni's search for gamma-ray bursts (this takes advantage of the automated telescope's ability to react as soon as a burst is seen and take a series of snapshots of the fading burst), Richard Ellis's search for supernovae to test whether the universe's expansion is accelerating or not, and S. George Djorgovski's quasar search.

The camera for the Palomar QUEST Survey was a mosaic of 112 charge-coupled devices (CCDs) covering the whole (4 degree by 4 degree) field of view of the Schmidt telescope. At the time it was built, it was the largest CCD mosaic used in an astronomical camera. This instrument was used to produce The Big Picture, the largest astronomical photograph ever produced. [28] The Big Picture is on display at Griffith Observatory.

Current research

Current research programs on the 200-inch Hale Telescope cover the range of the observable universe, including studies on near-Earth asteroids, outer Solar System planets, Kuiper Belt objects, star formation, exoplanets, [29] black holes and x-ray binaries, supernovae and other transient source followup, and quasars/Active Galactic Nuclei. [30]

The 48-inch Samuel Oschin Schmidt Telescope operates robotically, and supports a new transient astronomy sky survey, the Zwicky Transient Facility (ZTF). [5]

The 60-inch telescope operates robotically, and supports ZTF by providing rapid, low-dispersion optical spectra for initial transient classification using the for-purpose Spectral Energy Distribution Machine (SEDM) [31] integral field spectrograph.

Visiting and public engagement

Greenway Visitor Center at Palomar Observatory, with a gift shop Greenway Visitor Center.jpg
Greenway Visitor Center at Palomar Observatory, with a gift shop

Palomar Observatory is an active research facility. However, selected observatory areas are open to the public during the day. Visitors can take self-guided tours of the 200-inch telescope daily from 9 a.m. to 3 p.m. The observatory is open 7 days a week, year round, except for December 24 and 25 and during times of inclement weather. Guided tours of the 200-inch Hale Telescope dome and observing area are available Saturdays and Sundays from April through October. Behind-the-scenes tours for the public are offered through the community support group, Palomar Observatory Docents. [32]

Palomar Observatory also has an on-site museum—the Greenway Visitor Center [21] containing observatory and astronomy-relevant exhibits, a gift shop, [33] and hosts periodic public events. [34]

For those unable to travel to the observatory, Palomar provides an extensive virtual tour that provides virtual access to all the major research telescopes on-site, the Greenway Center, and has extensive embedded multimedia to provide additional context. [35] Similarly the observatory actively maintains an extensive website [36] and YouTube channel [37] to support public engagement.

The observatory is located off State Route 76 in northern San Diego County, California, two hours' drive from downtown San Diego and three hours' drive from central Los Angeles ( UCLA, LAX airport ). [38] Those staying at nearby Palomar Campground can visit Palomar Observatory by hiking 2.2 miles (3.5 km) up Observatory Trail. [39]

Climate

Palomar has a hot-summer Mediterranean climate (Köppen Csa).

Climate data for Palomar Observatory (1991–2020 normals, extremes 1938–present)
MonthJanFebMarAprMayJunJulAugSepOctNovDecYear
Record high °F (°C)82
(28)
77
(25)
82
(28)
83
(28)
91
(33)
104
(40)
100
(38)
100
(38)
100
(38)
97
(36)
80
(27)
80
(27)
104
(40)
Mean maximum °F (°C)63.4
(17.4)
63.9
(17.7)
69.5
(20.8)
76.1
(24.5)
82.0
(27.8)
88.7
(31.5)
92.9
(33.8)
92.0
(33.3)
88.3
(31.3)
81.0
(27.2)
71.5
(21.9)
64.8
(18.2)
94.3
(34.6)
Mean daily maximum °F (°C)51.4
(10.8)
51.0
(10.6)
56.0
(13.3)
61.3
(16.3)
69.3
(20.7)
78.5
(25.8)
84.3
(29.1)
84.4
(29.1)
79.3
(26.3)
69.1
(20.6)
58.2
(14.6)
50.7
(10.4)
66.1
(18.9)
Mean daily minimum °F (°C)37.1
(2.8)
36.1
(2.3)
38.7
(3.7)
41.8
(5.4)
48.4
(9.1)
57.0
(13.9)
63.9
(17.7)
64.5
(18.1)
59.5
(15.3)
50.8
(10.4)
42.5
(5.8)
36.6
(2.6)
48.1
(8.9)
Mean minimum °F (°C)24.4
(−4.2)
24.0
(−4.4)
25.4
(−3.7)
28.1
(−2.2)
33.4
(0.8)
41.2
(5.1)
55.3
(12.9)
55.1
(12.8)
45.5
(7.5)
36.8
(2.7)
29.0
(−1.7)
23.9
(−4.5)
19.8
(−6.8)
Record low °F (°C)8
(−13)
12
(−11)
16
(−9)
19
(−7)
24
(−4)
28
(−2)
36
(2)
36
(2)
30
(−1)
18
(−8)
17
(−8)
8
(−13)
8
(−13)
Average precipitation inches (mm)5.93
(151)
7.34
(186)
4.61
(117)
2.00
(51)
0.89
(23)
0.17
(4.3)
0.29
(7.4)
0.68
(17)
0.48
(12)
1.21
(31)
2.25
(57)
4.56
(116)
30.41
(772)
Average snowfall inches (cm)6.2
(16)
10.6
(27)
3.1
(7.9)
3.5
(8.9)
0.0
(0.0)
0.0
(0.0)
0.0
(0.0)
0.0
(0.0)
0.0
(0.0)
0.0
(0.0)
0.4
(1.0)
2.4
(6.1)
26.2
(67)
Average precipitation days (≥ 0.01 in)6.57.35.93.92.30.41.11.31.32.03.25.841
Average snowy days (≥ 0.1 in)1.22.10.91.10.00.00.00.00.00.00.31.57.1
Source: NOAA [40]

Selected books

See also

Related Research Articles

<span class="mw-page-title-main">Charles T. Kowal</span> American astronomer

Charles Thomas Kowal was an American astronomer known for his observations and discoveries in the Solar System. As a staff astronomer at Caltech's Mount Wilson and Palomar Mountain observatories between 1961 and 1984, he found the first of a new class of Solar System objects, the centaurs, discovered two moons of the planet Jupiter, and discovered or co-discovered a number of asteroids, comets and supernovae. He was awarded the James Craig Watson Medal for his contributions to astronomy in 1979.

<span class="mw-page-title-main">Jean Mueller</span> American astronomer

Jean Mueller is an American astronomer and discoverer of comets, minor planets, and a large number of supernovas at the U.S. Palomar Observatory in California.

<span class="mw-page-title-main">Hale Telescope</span> Telescope at Palomar Observatory in California, USA

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 National Geographic Society – Palomar Observatory Sky Survey was a major astronomical survey, that took almost 2,000 photographic plates of the night sky. It was conducted at Palomar Observatory, California, United States, and completed by the end of 1958.

<span class="mw-page-title-main">Schmidt camera</span> Astrophotographic telescope

A Schmidt camera, also referred to as the Schmidt telescope, is a catadioptric astrophotographic telescope designed to provide wide fields of view with limited aberrations. The design was invented by Bernhard Schmidt in 1930.

<span class="mw-page-title-main">Robotic telescope</span>

A robotic telescope is an astronomical telescope and detector system that makes observations without the intervention of a human. In astronomical disciplines, a telescope qualifies as robotic if it makes those observations without being operated by a human, even if a human has to initiate the observations at the beginning of the night or end them in the morning. It may have software agents using artificial intelligence that assist in various ways such as automatic scheduling. A robotic telescope is distinct from a remote telescope, though an instrument can be both robotic and remote.

The Digitized Sky Survey (DSS) is a digitized version of several photographic astronomical surveys of the night sky, produced by the Space Telescope Science Institute between 1983 and 2006.

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<span class="mw-page-title-main">Samuel Oschin telescope</span>

The Samuel Oschin telescope, also called the Oschin Schmidt, is a 48-inch-aperture (1.22 m) Schmidt camera at the Palomar Observatory in northern San Diego County, California. It consists of a 49.75-inch Schmidt corrector plate and a 72-inch (f/2.5) mirror. The instrument is strictly a camera; there is no provision for an eyepiece to look through it. It originally used 10- and 14-inch glass photographic plates. Since the focal plane is curved, these plates had to be preformed in a special jig before being loaded into the camera.

The UK Schmidt Telescope (UKST) is a 1.24 metre Schmidt telescope operated by the Australian Astronomical Observatory ; it is located adjacent to the 3.9 metre Anglo-Australian Telescope at Siding Spring Observatory, Australia. It is very similar to the Samuel Oschin telescope in California. The telescope can detect objects down to magnitude 21 after an hour of exposure on photographic plates.

The Quasar Equatorial Survey Team (QUEST) is a joint venture between Yale University, Indiana University, and Centro de Investigaciones de Astronomia (CIDA) to photographically survey the sky using a digital camera, an array of 112 charge-coupled devices. Since 2009, it has used the 1 m ESO Schmidt Telescope in Chile. From 2003–2007, it used the 48 inch (1.22 m) Samuel Oschin telescope at the Palomar Observatory. Before that, it had used the 1.0-metre Schmidt telescope at the Llano del Hato National Astronomical Observatory in Venezuela.

<span class="mw-page-title-main">Llano del Hato National Astronomical Observatory</span> Observatory

The Llano del Hato National Astronomical Observatory is an astronomical observatory in Venezuela. It is 3600 meters above sea level and is the country's main observatory. It is situated above the village of Llano del Hato in the Venezuelan Andes, not far from Apartaderos which lies about 50 kilometers north-east of Mérida, Mérida State.

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The Palomar Transient Factory, was an astronomical survey using a wide-field survey camera designed to search for optical transient and variable sources such as variable stars, supernovae, asteroids and comets. The project completed commissioning in summer 2009, and continued until December 2012. It has since been succeeded by the Intermediate Palomar Transient Factory (iPTF), which itself transitioned to the Zwicky Transient Facility in 2017/18. All three surveys are registered at the MPC under the same observatory code for their astrometric observations.

The Palomar–Leiden survey (PLS) was a successful astronomical survey to study faint minor planets in a collaboration between the U.S Palomar Observatory and the Dutch Leiden Observatory, and resulted in the discovery of thousands of asteroids, including many Jupiter trojans.

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The Zwicky Transient Facility is a wide-field sky astronomical survey using a new camera attached to the Samuel Oschin Telescope at the Palomar Observatory in California, United States. Commissioned in 2018, it supersedes the (Intermediate) Palomar Transient Factory (2009–2017) that used the same observatory code. It is named after the astronomer Fritz Zwicky.

<span class="mw-page-title-main">Palomar globular clusters</span> Faint globular clusters in the Milky Way galaxy

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Further reading