General map or image of a region of the sky with no specific observational target
Composite image of the GOODS-South field, result of a deep survey using two of the four giant 8.2-metre telescopes composing ESO's Very Large TelescopeGamma-ray pulsars detected by the Fermi Gamma-ray Space Telescope
An astronomical survey is a general map or image of a region of the sky (or of the whole 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.[1]
Sky surveys, unlike targeted observation of a specific object, allow astronomers to catalog celestial objects and perform statistical analyses on them without complex corrections for selection effects. In some cases, an astronomer interested in a particular object will find that survey images are sufficient to make new telescope time entirely unnecessary.
Surveys also help astronomers choose targets for closer study using larger, more powerful telescopes. If previous observations support a hypothesis, a telescope scheduling committee is more likely to approve new, more detailed observations to test it.
The wide scope of surveys makes them ideal for finding foreground objects that move, such as asteroids and comets. An astronomer can compare existing survey images to current observations to identify changes; this task can even be performed automatically using image analysis software. Besides science, these surveys also detect potentially hazardous objects. Similarly, images of the same object taken by different surveys can be compared to detect transient astronomical events such as variable stars.[2]
Hipparchus - created the first known star catalogue with more than 850 stars. The data was incorporated into the Almagest along with the first list of stellar magnitudes and was the primary astronomical reference until modern times, 190-120 BC.
Astrographic Catalogue - international astronomical survey of the entire sky. The survey was performed by 18 observatories using over 22,000 photographic plates. The results have been the basis of comparison for all subsequent surveys, 1887–1975.
Henry Draper Catalogue - spectral classifications based on photographic plates, 1918–1924, extension 1925–1936
Catalina Sky Survey - an astronomical survey to discover comets and asteroids.
DESI Legacy Imaging Surveys (Legacy Surveys) - large imaging survey of the extragalactic sky, in three bands and covering one third of the sky, 2013–present
The 2-micron All-Sky Survey (2MASS), a ground-based all sky survey at J, H, and Ks bands (1.25, 1.65, and 2.17 μm) 1997–2001
Akari (Astro-F) a Japanese mid and far infrared all-sky survey satellite, 2006–2008
Wide-field Infrared Survey Explorer (WISE) was launched in December 2009 to begin a survey of 99% of the sky at wavelengths of 3.3, 4.7, 12, and 23 μm. The telescope is over a thousand times as sensitive as previous infrared surveys. The initial survey, consisting of each sky position imaged at least eight times, was completed by July 2010.
UKIRT Infrared Deep Sky Survey (UKIDSS) – a collection of ground based northern hemisphere surveys (GPS, GCS, LAS, DXS, UDS) using the WFCAM camera on UKIRT, some wide and some very deep, in Z, Y, J, H, & K bands 2005–
VISTA public surveys – a collection of ground based southern hemisphere surveys (VVV, VMC, VHS, VIKING, VIDEO, UltraVISTA), of various areas and depths, in Z, Y, J, H, & Ks bands, 2009–present
GALEX Arecibo SDSS Survey GASS[13] designed to measure the neutral hydrogen content of a representative sample of ~1000 massive, galaxies
C-BASS – On-going 5 GHz all sky survey to aid in the subtraction of galactic foregrounds from maps of the Cosmic Microwave Background
EMU – A large radio continuum survey covering 3/4 of the sky, expected to discover about 70 million galaxies
GMRT - The Giant Metrewave Radio Telescope's TGSS ADR mapped the sky at 150 MHz.
HTRU – A pulsar and radio transients survey of the northern and southern sky using the Parkes Radio Telescope and the Effelsberg telescope.
Gamma-ray
Fermi Gamma-ray Space Telescope, formerly referred to as the "Gamma-ray Large Area Space Telescope (GLAST)." 2008–present; the goal for the telescope's lifetime is 10 years.
Multi-wavelength surveys
GAMA – the Galaxy And Mass Assembly survey[14] combines data from a number of ground- and space-based observatories together with a large redshift survey, performed at the Anglo-Australian Telescope. The resulting dataset aims to be a comprehensive resource for studying the physics of the galaxy population and underlying mass structures in the recent universe.[15]
GOODS – The Great Observatories Origins Deep Survey.
^Driver, Simon P.; Norberg, Peder; Baldry, Ivan K.; Bamford, Steven P.; Hopkins, Andrew M.; Liske, Jochen; Loveday, Jon; Peacock, John A.; Hill, D. T.; Kelvin, L. S.; Robotham, A. S. G.; Cross, N. J. G.; Parkinson, H. R.; Prescott, M.; Conselice, C. J.; Dunne, L.; Brough, S.; Jones, H.; Sharp, R. G.; Van Kampen, E.; Oliver, S.; Roseboom, I. G.; Bland-Hawthorn, J.; Croom, S. M.; Ellis, S.; Cameron, E.; Cole, S.; Frenk, C. S.; Couch, W. J.; Graham, A. W.; et al. (2009). "GAMA: towards a physical understanding of galaxy formation". Astronomy & Geophysics. 50 (5): 5.12. arXiv:0910.5123. Bibcode:2009A&G....50e..12D. doi:10.1111/j.1468-4004.2009.50512.x. S2CID119214918.
