Reference AM 1.5 Spectrum
American Society for Testing and Materials (ASTM) Terrestrial Reference Spectra for Photovoltaic Performance Evaluation
solar zenith angle 48.19°, "Global tilt"
Spectrum 1: SUN EditDelete
Reference AM 1.5 Spectrum
|Ballast||- no ballast or default/unknown ballast -|
Colorimetry is the science to describe physically the human color perception. The wavelength range 380 nm - 780 nm is visible to humans and detected by three different photoreceptors. Many Reptiles see the range 350 nm - 800 nm and have an additional UV photoreceptor in their retina.
Whereas a spectrometer measures the intensity in every tiny wavelength interval resulting in thousands of individual intensities, the human eye only measures three intensities detected by the three cones. The same is true for the reptile eye with usually three or four photoreceptors. Effectively the detailled spectrum displayed above reduces to a much compacter bar graph displayed below. The photoreceptor sensitivites from these L-Cone, M-Cone, S-Cone, and U-Cone are used, they are chosen as an average of measured reptile photoreceptor sensitivity curves. The bar graph also shows as reference the intensity seen by the three or four photoreceptors for average sunlight (id 1).
From these three numbers the colour coordinate and the correlated colour temperature for humans are calculated using the CIE standard method. I adapted this concept to a "3 cone reptile (M,S,U)" and a "4 cone reptile (L,M,S,U)". I am sure, that this adaption to other colour spaces makes sense mathematically and this is also done in scientific research regarding colour vision of animals, however I have not seen calculation of colour temperatures for other animals in the scientific literature. Even if it is hypothetical, at least this shows, how arbitrary the colour temperature is, and that the colour temperature calculated for humans does not apply to reptiles. The colour spaces also show the colour coordinates of different phases of daylight ((ids 1, 338 – 451, 511 – 513 ), indicated by crosses, coloured in the appriximate colour perceived by a human.
|Human (CIE)||3 cone reptile||4 cone reptile|
|Colour Coordinate||( 0.33 ; 0.34 )||( 0.42 ; 0.37 )||( 0.29 ; 0.3 ; 0.26 )|
|CCT||5500 Kelvin||4600 Kelvin||5000 Kelvin|
|colour space||3-D-graph not implemented yet|
Vitamin D3 is produced by UVB radiation around 300 nm. 7DHC/ProD3 present in the skin is converted to PreD3 when absorbing an UV photon. PreD3 can be converted back to ProD3, to Lumisterol, or to Tachysterol when absorbing another UV photon or can be converted to Vitamin D3 in a warm environment.
The equilibrium of the photoproducts depends on the actual UV spectrum in the range 250 nm - 340 nm. With knowledge of the conversion probabilities and absorption spectra of 7DHC, PreD3, Tachysterol, and Lumisterol it is possible to calculate the ratio of photoproducts in equilibrium. This is based on scientific literature , however the constants that are used for the calculation are not well calibrated with experiments. It is therefore not a solid method, but I consider it useful as a first guess how natural a UV spectrum is.
Caveat: This evaluation is extremely sensitive to the qualitiy of the spectral measurement in the range 220 nm - 340 nm. High quality spectrometers and good background calibration is needed to get the noise below 300 nm low enough for this evaluation. Please check at least the UV graph above for noise.
The ratio of the two solarmeters 6.2 (UVB) and 6.5 (UV index) readings has proven a useful and very simply number to acess the spectral shape in the vitamin-d3-active region.
The calculation method is a numerical implementation (Simpson's rule) of the formula
To learn more about calculating effective irradiances and radiometers I recommend this excellent report on UVB meters: Characterizing the Performance of Integral Measuring UV-Meters (pdf).
The numbers in the following tables can also be used to estimate certain (effective) irradiances from radiomer readings. Example: If the database lists
- range: UVB (US) = 13.8 µW/cm²
- radiometer: Solarmeter 6.2 = 19.6 µW/cm²
UVA (EU) ( 315 nm - 400 nm) 4540 µW/cm² = 45.4 W/m² UVA (US) ( 320 nm - 400 nm) 4460 µW/cm² = 44.6 W/m² UVB (EU) ( 280 nm - 315 nm) 68.2 µW/cm² = 0.682 W/m² UVB (US) ( 280 nm - 320 nm) 152 µW/cm² = 1.52 W/m² UVC ( 0 nm - 280 nm) 0 µW/cm² = 0 W/m² vis. UVA ( 350 nm - 380 nm) 1850 µW/cm² = 18.5 W/m² purple ( 380 nm - 420 nm) 3740 µW/cm² = 37.4 W/m² blue ( 420 nm - 490 nm) 10000 µW/cm² = 100 W/m² green ( 490 nm - 575 nm) 13000 µW/cm² = 130 W/m² yellow ( 575 nm - 585 nm) 1500 µW/cm² = 15 W/m² orange ( 585 nm - 650 nm) 9380 µW/cm² = 93.8 W/m² red ( 650 nm - 780 nm) 15800 µW/cm² = 158 W/m² VIS ( 380 nm - 780 nm) 53400 µW/cm² = 534 W/m² PAR ( 400 nm - 700 nm) 43000 µW/cm² = 430 W/m² total ( 0 nm - 0 nm) 100000 µW/cm² = 1000 W/m² UVA1 ( 315 nm - 350 nm) 1310 µW/cm² = 13.1 W/m² VIS Rep3 ( 350 nm - 600 nm) 32300 µW/cm² = 323 W/m² VIS Rep4 ( 350 nm - 700 nm) 46200 µW/cm² = 462 W/m² IRA ( 700 nm - 1400 nm) 41500 µW/cm² = 415 W/m² IRB ( 1400 nm - 3000 nm) 10200 µW/cm² = 102 W/m²
Erythema 3.66 UV-Index Pyrimidine dimerization of DNA 52.4 µW/cm² Photoceratitis 4.51 µW/cm² Photoconjunctivitis 0.0343 µW/cm² DNA Damage 0.116 Vitamin D3 12.7 µW/cm² Photosynthesis 30500 µW/cm² Luminosity 116000 lx Human L-Cone 17300 µW/cm² Human M-Cone 14300 µW/cm² Human S-Cone 8190 µW/cm² CIE X 15600 µW/cm² CIE Y 16000 µW/cm² CIE Z 15200 µW/cm² PAR 203000000 mol photons Extinction preD3 0.16 m²/mol Extinction Tachysterol 0.609 m²/mol Extinction Lumisterol 0.00635 m²/mol Extinction 7DHC 0.0026 m²/mol L-Cone 14800 µW/cm² M-Cone 15300 µW/cm² S-Cone 13400 µW/cm² U-Cone 7780 µW/cm² UVR - ICNIRP 2004 1.99 Rel Biol Eff Melatonin Supression 12600 µW/cm² Blue Light Hazard 9410 µW/cm² (81.3 µW/cm² per 1000 lx) CIE 174:2006 PreVit D3 13.5 µW/cm² Lumen Reptil 120000 "pseudo-lx" Vitamin D3 Degradation 33.4 µW/cm²
Solarmeter 6.2 (UVB, pre 2010) 244 µW/cm² Solarmeter 6.5 (UV-Index, pre 2010) 4.29 Leybold UVB 153 µW/cm² Leybold UVA 2310 µW/cm² Leybold UVC 0.000114 µW/cm² DeltaOhm UVB 657 µW/cm² DeltaOhm UVC 60.3 µW/cm² Vernier UVB 31.6 µW/cm² Vernier UVA 1810 µW/cm² Gröbel UVA 2580 µW/cm² Gröbel UVB 63.7 µW/cm² Gröbel UVC -0.0484 µW/cm² Solarmeter 6.4 (D3) 13.4 IU/min UVX-31 786 µW/cm² IL UVB 0.122 µW/cm² IL UVA 2700 µW/cm² Solarmeter 6.5 (UVI, post 2010) 3.85 UV-Index Solarmeter 6.2 (UVB, post 2010) 187 µW/cm² (Solarmeter Ratio = 48.4) Solarmeter AlGaN 6.5 UVI sensor 64.4 UV Index GenUV 7.1 UV-Index 4.75 UV-Index Solarmeter 10.0 (Global Power) 1000 W/m² Solarmeter 4.0 (UVA) 44.6 mW/cm²