A photometer is an instrument for measuring photometric quantities such as luminous flux, illuminance or luminance, widely used in astronomy and lighting science.
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ResolutionNot stated as a numeric figure in the cited source. 1 The cited source gives no numeric sensitivity or resolution figures for photometers generally; it describes visual comparison and photon-counting methods without stating detection thresholds. Operating RangeNot stated as a numeric figure in the cited source. 1 The cited source gives no numeric light-intensity range for photometers generally, only historical method descriptions and a detector time-resolution figure unrelated to intensity range. Invented Year MeasuresLuminous flux, illuminance or luminance. 1 Operating PrincipleDetects light by converting it into an electric current using a photoresistor, photodiode or photomultiplier; several rival mechanical and electrical designs were already in common use by the 1860s. 1 Classification
Instrument ClassMeasurement or Metrology Instrument 1 Connections
Invented By
One of several early photometer designs in common use by 1861, alongside Ritchie's photometer and shadow extinction methods; no single fixed invention year is established for the instrument class.
Source Photometer (Wikipedia)
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Source Photometer (Wikipedia)
Used In
Source Photometer (Wikipedia)
Chemistry, Disciplines The photometer is a principal instrument in analytical chemistry.
Source Photometer (Wikipedia)
Sources
1. Photometer (Wikipedia)
WikipediaLead section
A photometer is an instrument for measuring photometric quantities such as luminous flux, illuminance, or luminance.
Overview section
Most photometers detect the light with photoresistors, photodiodes or photomultipliers.
- History section
- Photon counting section
Lede, instrument class
A photometer is an instrument for measuring photometric quantities such as luminous flux, illuminance or luminance, widely used in astronomy and lighting science.
- Invented By: Benjamin Thompson, Count Rumford
Used In: Chemistry, Applications section
The photometer has become one of the principal instruments in biochemistry and analytical chemistry.
View the Source 2. Wikipedia: Pierre Bouguer
WikipediaCareer sectionQuote, Career section
In 1729 he published Essai d'optique sur la gradation de la lumiere, the object of which is to define the quantity of light lost by passing through a given extent of the atmosphere, and became the first known discoverer of what is now more commonly known as the Beer-Lambert law.
Open Questions (1 open question)
When was the photometer invented, and by whom?
Wikipedia's Photometer article states three photometer types (Rumford's, Ritchie's, and shadow-extinction types) were already in common use by 1861, but names no invention year or event for the instrument itself. The existing invented edge already credits Benjamin Thompson (Count Rumford), but neither his own Wikipedia biography nor the Photometer or Photometry (optics) articles state a year. A web search found a plausible date, Rumford's 1794 paper in Philosophical Transactions vol. 84, but the corroborating page (Citizendium) returned HTTP 403 and was not visited, so it is not citable under the quote-capture duty.
What would resolve this A fetchable, quotable page (not blocked) that states the year Rumford, Ritchie or an earlier figure such as Bouguer or Lambert first built or described a working photometer, ideally naming the specific publication (Rumford's 1794 Philosophical Transactions paper is the leading candidate).
History of sciencePhotometer (Wikipedia)
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