I have realised that the transmission of a Cokin BLUE 80B photo-filter applied to the solar (outside the atmosphere) energy flux spectrum provides a remarkably good analogue for the colour of the twilight sky within the visible part of the spectrum. The plot shows a measurement of the twilight sky with a solar elevation of -8° (green line) compared with the Cokin-filtered intrinsic solar spectral energy distribution (blue line). The filter thus represents the the effect of the long atmospheric path taken by sunlight during twilight (The Blue Hour). There are differences in detail: the analogue is brighter than twilight in the far red (beyond about 680nm) and also peaks at a shorter wavelength in the blue, but is does provide a rather realistic twilight blue. The riboflavin fluorescence spectrum (red line) is of interest for animal vision but is incidental to this this post. Note: The slight wavelength shift between the two solar spectra is understood: I resampled the solar flux spectrum onto the original JAZ wavelength vector before I applied my calibration correction. This small difference is not important for this plot.
Twilight: Blue Light Filter - 1 Minute App Showcase
This Is Why You Should Appreciate the Cinematic Filmmaking of 'Twilight
The Audemars Piguet Royal Oak Perpetual Calendar Blue Ceramic
Best cameras for astrophotography 2024: Shoot for the stars
Fermion - AS7341 11-channel visible light sensor - DFRobot SEN0365 Botland - Robotic Shop
Twilight Fans Are Freaking Out Over Seeing The Movie Without Its Blue Filter
New 2024 Mercedes-Benz GLS AMG® GLS 63 4MATIC®+ SUV SUV in Minnetonka #76849
What are the potential risks of exposure to blue light from cell phones and LED lights? Can it harm your eyes or disturb your circadian rhythm/sleep cycle? - Quora
Ready For Bed? How to Stop Blue Light From Disturbing Your Sleep
Blue Hour Photography: The Definitive Guide
Ontologia Kentin Jivek
The Edgeless & Ever-Shifting Gradient: An Encyclopaedic and Evolving Spectrum of Gradient Knowledge