Search results
Results From The WOW.Com Content Network
Factor ()Multiple Value Item 0 0 lux 0 lux Absolute darkness 10 −4: 100 microlux 100 microlux: Starlight overcast moonless night sky [1]: 140 microlux: Venus at brightest [1]: 200 microlux
This is a list of sources of light, the visible part of the electromagnetic spectrum.Light sources produce photons from another energy source, such as heat, chemical reactions, or conversion of mass or a different frequency of electromagnetic energy, and include light bulbs and stars like the Sun. Reflectors (such as the moon, cat's eyes, and mirrors) do not actually produce the light that ...
Unexpectedly bright visible objects can be produced by gravitational lensing of very distant objects by extremely massive objects closer to Earth. However, this usually occurs with objects much more distant than ASASSN-15lh, and there are no observations indicating the presence of a galaxy cluster suitable to produce a lensing effect.
An illustration of light sources from magnitude 1 to 3.5, in 0.5 increments In astronomy , magnitude is a measure of the brightness of an object , usually in a defined passband . An imprecise but systematic determination of the magnitude of objects was introduced in ancient times by Hipparchus .
dΣ is an infinitesimal area (m 2) of the source containing the specified point; dΩ Σ is an infinitesimal solid angle containing the specified direction; and; θ Σ is the angle between the normal n Σ to the surface dΣ and the specified direction. [7] If light travels through a lossless medium, the luminance does not change along a given ...
The frequency of light used in the definition corresponds to a wavelength in a vacuum of 555 nm, which is near the peak of the eye's response to light. If the 1 candela source emitted uniformly in all directions, the total radiant flux would be about 18.40 mW, since there are 4 π steradians in a sphere.
List of star systems within 75–80 light-years; List of star systems within 80–85 light-years; List of star systems within 85–90 light-years; List of star systems within 90–95 light-years; List of star systems within 95–100 light-years; List of nearest stars by spectral type; List of nearest bright stars; List of brightest stars
The photopic includes the CIE 1931 standard (solid), the Judd-Vos 1978 modified data (dashed), and the Sharpe, Stockman, Jagla & Jägle 2005 data (dotted). The horizontal axis is wavelength in nm. Photometry is a branch of optics that deals with measuring light in terms of its perceived brightness to the human eye. [1]