| Alternative names | DSS |
|---|---|
| Coordinates | 31°16′37″S149°03′58″E / 31.276811°S 149.0661°E |
| Observatory code | 260 |
| Website | archive |
 Related media on Commons | |
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.
The term Digitized Sky Survey originally referred to the publication in 1994 of a digital version of an all-sky photographic atlas used to produce the first version of the Guide Star Catalog. [1] [2] For the northern sky, the National Geographic Society – Palomar Observatory Sky Survey E-band (red, named after the Eastman Kodak IIIa-E emulsion used), provided almost all of the source data (plate code "XE" in the survey). [3] For the southern sky, the J-band (blue, Eastman Kodak IIIa-J) of the ESO/SERC Southern Sky Atlas (known as the SERC-J, code "S") [4] [5] [6] and the "quick" V-band (blue or V in the Johnson–Kron–Cousins system, Eastman Kodak IIa-D) SERC-J Equatorial Extension (SERC-QV, code "XV"), from the UK Schmidt Telescope at the Australian Siding Spring Observatory, were used. [7] Three supplemental plates in the V-band from the SERC and Palomar surveys are included (code "XX"), with shorter exposure times for the fields containing the Andromeda Galaxy, the Large and the Small Magellanic Cloud. [8] The publication of a digital version of these photographic collections has subsequently become known as the First Generation DSS or DSS1.
After the original 1994 publication, more digitizations were made using recently completed photographic surveys, and released as the Second Generation DSS or DSS2. Second Generation DSS consists of three spectra bands, blue, red, and near infrared. The red part was first to complete, [9] and includes the F-band (red, Eastman Kodak IIIa-F) plates from the Palomar Observatory Sky Survey II, made with the Oschin Schmidt Telescope at Palomar Observatory for the northern sky. [10] [11] [12] Red band sources for the southern sky include the short red (SR) plates of the SERC I/SR Survey and Atlas of the Milky Way and Magellanic Clouds (referred to as AAO-SR in DSS2), [13] the Equatorial Red (SERC-ER), [5] and the F-band Second Epoch Survey (referred to as AAO-SES in DSS2, AAO-R in the original literature), [14] all made with the UK Schmidt Telescope at Anglo-Australian Observatory. [15]
The Digitized Sky Survey was produced by the Catalogs and Survey Branch (CASB) of the Space Telescope Science Institute (STScI). They scanned plates using one of two Perkin-Elmer PDS 2020G microdensitometers. The pixel size was 25 ("First Generation", DSS1) or 15 micrometres ("Second Generation", DSS2), corresponding to 1.7 or 1.0 arcseconds in the source material. [16] The scanning resulted in images 14,000 x 14,000 (DSS1) or 23,040 x 23,040 pixels (DSS2) in size, [17] or approximately 0.4 (DSS1) and 1.1 gigabytes (DSS2) each. The scanning of First Generation DSS takes a little under seven hours per plate to complete. Due to the large size of the images, they were compressed using an H-transform algorithm. [18] [19] This algorithm is lossy, but adaptive, and preserves most of the information in the original. [20] Most of the First Generation DSS files were shrunk by a factor of seven. [21] Similar methods were used in the production of the "Second Generation" DSS, but the microdensitometers have since been modified for multi-channel operation, in order to keep the scan time under 12 hours per plate. [22]
The CASB has also published several companion scientific products. The most notable is a photometric calibration of part of the "First Generation" DSS. It allows photometric measurements to be made using the digital northern POSS-E, southern SERC-J, and southern Galactic Plane SERC-V data. [23]
The compressed version of the First Generation DSS was published by the STScI and the Astronomical Society of the Pacific (ASP) on 102 CD-ROMs in 1994, under the name "Digitized Sky Survey." [24] It has also been made available online by the STScI [25] [26] and several other facilities in databases that can be queried over the web. The moniker "First Generation" was added later.
In 1996, a more highly compressed version of the DSS was published by the STScI and ASP under the name RealSky. RealSky files were compressed by a factor of roughly 100. RealSky consequently took up less space, but the additional compression made it inappropriate for use in photometry and fine detail in the images was degraded. [27] [28]
The Second Generation DSS has appeared steadily over the course of several years. In 2006, the Second Generation DSS (second epoch POSS-II and SES surveys) was finished, and distributed on CD-ROM to partner institutions. Generally, the data are available through WWW services at partner institutions.
Photographic plates preceded photographic film as a capture medium in photography. The light-sensitive emulsion of silver salts was coated on a glass plate, typically thinner than common window glass. They were heavily used in the late 19th century and declined through the 20th. They were still used in some communities until the late 20th century.
Palomar Observatory is an astronomical research observatory in the Palomar Mountains of San Diego County, California, United States. 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, and the National Astronomical Observatories of China.
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.
A laser guide star is an artificial star image created for use in astronomical adaptive optics systems, which are employed in large telescopes in order to correct atmospheric distortion of light. Adaptive optics (AO) systems require a wavefront reference source of light called a guide star. Natural stars can serve as point sources for this purpose, but sufficiently bright stars are not available in all parts of the sky, which greatly limits the usefulness of natural guide star adaptive optics. Instead, one can create an artificial guide star by shining a laser into the atmosphere. Light from the beam is reflected by components in the upper atmosphere back into the telescope. This star can be positioned anywhere the telescope desires to point, opening up much greater amounts of the sky to adaptive optics.
The Guide Star Catalog (GSC), also known as the Hubble Space Telescope, Guide Catalog (HSTGC), is a star catalog compiled to support the Hubble Space Telescope with targeting off-axis stars. GSC-I contained approximately 20,000,000 stars with apparent magnitudes of 6 to 15. GSC-II contains 945,592,683 stars out to magnitude 21. As far as possible, binary stars and non-stellar objects have been excluded or flagged as not meeting the requirements of Fine Guidance Sensors. This is the first full sky star catalog created specifically for navigation in outer space.
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.
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.
La Silla Observatory is an astronomical observatory in Chile with three telescopes built and operated by the European Southern Observatory (ESO). Several other telescopes are located at the site and are partly maintained by ESO. The observatory is one of the largest in the Southern Hemisphere and was the first in Chile to be used by ESO.
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 inches (1.264 m) Schmidt corrector plate and a 72 inches (1.8 m) (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 inches (25 cm) and 14 inches (36 cm) 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.
An astronomical survey is a general map or image of a region of the sky that lacks a specific observational target. Alternatively, an astronomical survey may comprise a set of images, spectra, or other observations of objects that share a common type or feature. Surveys are often restricted to one band of the electromagnetic spectrum due to instrumental limitations, although multiwavelength surveys can be made by using multiple detectors, each sensitive to a different bandwidth.
The Royal Observatory, Edinburgh (ROE) is an astronomical institution located on Blackford Hill in Edinburgh. The site is owned by the Science and Technology Facilities Council (STFC). The ROE comprises the UK Astronomy Technology Centre (UK ATC) of STFC, the Institute for Astronomy of the School of Physics and Astronomy of the University of Edinburgh, and the ROE Visitor Centre.
30705 Idaios is a Jupiter trojan from the Trojan camp, approximately 45 kilometers in diameter. It was discovered during the third Palomar–Leiden Trojan survey at the Palomar Observatory in California in 1977. The dark D-type asteroid has a rotation period of 15.7 hours. It was named after the Trojan herald Idaios from Greek mythology.
4754 Panthoos is a Jupiter trojan from the Trojan camp, approximately 53 kilometers in diameter. It was discovered during the third Palomar–Leiden Trojan survey on 16 October 1977, by Ingrid and Cornelis van Houten at Leiden, and Tom Gehrels at the Palomar Observatory in California. It is likely spherical in shape and has a longer-than-average rotation period of 27.68 hours. The assumed C-type asteroid is one of the 80 largest Jupiter trojans. It was named after Panthous (Panthoos) from Greek mythology.
Arp-Madore 1 is a globular cluster visible in the constellation Horologium, located 123.3 kiloparsecs away from Earth. It is one of the most distant known globular clusters of the Milky Way galaxy's halo; its distance gives it interest as a test case for gravitational theories. AM 1 has a visual magnitude of 15.07.
Stanislav George Djorgovski is an American scientist and scholar. He obtained his B.A. in astrophysics in 1979 at the University of Belgrade. After receiving his PhD in astronomy from U.C. Berkeley in 1985, he was a Harvard Junior Fellow until 1987 when he joined the faculty at the California Institute of Technology, where he is currently a professor of astronomy and data science.
Time-domain astronomy is the study of how astronomical objects change with time. Though the study may be said to begin with Galileo's Letters on Sunspots, the term now refers especially to variable objects beyond the Solar System. Changes over time may be due to movements or changes in the object itself. Common targets included are supernovae, pulsating stars, novas, flare stars, blazars and active galactic nuclei. Visible light time domain studies include OGLE, HAT-South, PanSTARRS, SkyMapper, ASAS, WASP, CRTS, GOTO and in a near future the LSST at the Vera C. Rubin Observatory.
The Abell Catalog of Planetary Nebulae was created in 1966 by George O. Abell and was composed of 86 entries thought to be planetary nebulae that were collected from discoveries, about half by Albert George Wilson and the rest by Abell, Robert George Harrington, and Rudolph Minkowski. All were discovered before August 1955 as part of the National Geographic Society – Palomar Observatory Sky Survey on photographic plates created with the 48-inch (1.2 m) Samuel Oschin telescope at Mount Palomar. Four are better known from previous catalogs: Abell 50 is NGC 6742, Abell 75 is NGC 7076, Abell 37 is IC 972, and Abell 81 is IC 1454. Another four were later rejected as not being planetaries: Abell 11, Abell 32, Abell 76, and Abell 85. Another three were also not included in the Strasbourg-ESO Catalogue of Galactic Planetary Nebulae (SEC): Abell 9, Abell 17, and Abell 64. Planetaries on the list are best viewed with a large aperture telescope and an OIII filter.
NeVe 1 is a supergiant elliptical galaxy, which is the central, dominant member and brightest cluster galaxy (BCG) of the Ophiuchus Cluster. It lies at a distance of about 411 million light-years away from Earth and is located behind the Zone of Avoidance region in the sky. It is the host galaxy of the Ophiuchus Supercluster eruption, the most energetic astronomical event known.
Data-driven astronomy (DDA) refers to the use of data science in astronomy. Several outputs of telescopic observations and sky surveys are taken into consideration and approaches related to data mining and big data management are used to analyze, filter, and normalize the data set that are further used for making Classifications, Predictions, and Anomaly detections by advanced Statistical approaches, digital image processing and machine learning. The output of these processes is used by astronomers and space scientists to study and identify patterns, anomalies, and movements in outer space and conclude theories and discoveries in the cosmos.
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