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(studying starlight through bandpass filters)

In astronomy, the term photometry is used for the study of the brightness (magnitude) of stars and other bodies, optionally using bandpass filters to measure magnitudes over specific spectral ranges, e.g., to determine color indices. The results of such observation may be called the star's photometry.

This is as opposed to a more complete characterization of the body's light via spectroscopy, which requires a more specialized instrument. Photometry has the advantage of requiring less light (apparent magnitude), thus can be done at a greater distance and can be used with many more stars. It also is naturally "multi-object", also making it much more efficient to survey many stars.

The passbands used have been standardized (photometric systems) to allow comparison and general use of photometric data.

Filters with different passband widths are used, according to need and light-availability, yielding some levels of spectral detail, but short of using full spectroscopy. For example, direct imaging of extra-solar planets offers limited light, making photometry more practical than spectroscopy. Some subtypes of photometry:


Referenced by:
aperture photometry
All Sky Automated Survey (ASAS)
All-Sky Compiled Catalogue (ASCC)
Catalog of Azzopardi & Vigneau (AzV)
band shifting
Balmer-break galaxy (BBG)
California-Kepler Survey (CKS)
Carlsberg Meridian Catalogue (CMC)
cosmic dust
Carnegie Supernova Project (CSP)
Cerro Tololo Inter-American Observatory (CTIO)
Dark Energy Survey (DES)
Deep Lens Survey (DLS)
exoplanet eclipse light curve
ESO Nearby Abell Cluster Survey (ENACS)
extremely red object (ERO)
Extreme Ultraviolet Explorer (EUVE)
first galaxies
forward model
galaxy SED
Hawaii K-band Galaxy Survey
Herschel Space Observatory
Bright Star Catalog (HR)
JHK photometric system (JHK)
Large Synoptic Survey Telescope (LSST)
Magellanic Clouds Photometric Survey (MCPS)
NOAO Deep Wide-field Survey (NDWFS)
photometric redshift (photo-z)
photometric system
Qatar Exoplanet Survey (QES)
Supernova Cosmology Project (SCP)
Sloan Digital Sky Survey (SDSS)
sky subtraction
SkyMapper Southern Survey (SMSS)
Swope Supernova Survey (SSS)
stellar parameter determination
stellar temperature determination
Strömgren photometric system
synthetic photometry
Type Ia supernova
UBV photometric system
VLT Survey Telescope (VST)
Wide Field Infrared Explorer (WIRE)