In modern astronomy, photometry is generally conducted using photoelectric detectors or charge-coupled devices. Filters are also used to control the exact wavelengths and colors of light that are measured. This gives astronomers a greater ability to analyze the photometric data scientifically.

Most photometry is obtained using filters that produce standard bandpasses. A bandpass is a well-defined range of wavelengths of light; for example, astronomers refer to the “V-band” as the bandpass of light that ranges in wavelength from about 500 nanometers to 600 nanometers, which encompasses blue-green, green, and yellow light. When astronomers worldwide obtain photometry in common bandpasses, their data and scientific results can be compared, contrasted, and analyzed much more effectively than if everyone used very different bandpasses.