has two meanings:
- In popular culture optical astronomy encompasses a wide variety of observations via telescopes that are sensitive in the range of visible light. Scientists would call this visible-light astronomy. It includes imaging, where a picture of some sort is made of the object; photometry, where the amount of light coming from an object is measured, spectroscopy, where the distribution of that light with respect to its wavelength is measured, and polarimetry where the polarisation state of that light is measured.
- Scientists use the term optical astronomy to mean astronomy at infrared, visible and ultraviolet wavelengths (i.e. observations using either infrared, visible or ultraviolet wavelengths of light). Observations at these wavelengths generally use optical components (mirrors, lenses and solid state digital detectors).