Astrophysics (index)about


(studying starlight through bandpass filters)

In astronomy, the term photometry is used for the study of the brightness (magnitude) of stars and other bodies, and often implies the use of bandpass filters (i.e., different bands) to measure magnitudes specifically over given spectral ranges, i.e., to determine color index. 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 has a greater range, i.e., can be used with many more stars.

Collected observations and models have associated color magnitudes and color indexes with various physical characteristics of stars. This has been standardized by using conventional filters, e.g., in photometric systems.

Filters with different passband widths are used, according to need and light-availability, yielding a number of levels of spectral detail short of using full spectroscopy. These can be of use in direct imaging extra-solar planets, for which limited light reaches Earth. Some conventional terms:


Referenced by:
aperture photometry
All Sky Automated Survey (ASAS)
Catalog of Azzopardi & Vigneau (AzV)
band shifting
Balmer-break galaxy (BBG)
California-Kepler Survey (CKS)
cosmic dust
Cerro Tololo Inter-American Observatory (CTIO)
Deep Lens Survey (DLS)
exoplanet eclipse light curve
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
UBV photometric system
VLT Survey Telescope (VST)
Wide Field Infrared Explorer (WIRE)