Laptop Screen & Blue Light

[solissydney (Ken)]

Reduce the health risk of the circadian- disrupting blue light from your PC and laptop at night.
A free program called f,lux works out when it is local sunset and quickly, or slowly, winds down the screen luminance and reduces the blue content of your screen. The next day the screen is back to normal. I have not yet tested the program but I suspect the program might also help in preserving ones night vision.
There are versions for Windows, Mac and Linux

http://www.sereopsis.com/flux/ typing in the address did not work for me,
But typing in 'f.lux' did.
Ken

[troypiggo (Troy)]

Typo in your link. It should be http://www.stereopsis.com/flux/
I suspect you'll upset other astro buddies if you use this near them at a dark site, as it'll probably still be near-white light. Red light is much better at maintaining your night-vision.

On my Mac I use a free program called RedScreen. Others use red gels over their monitors/screens.

[solissydney (Ken)]

Typo in the link that was sent me.
I for one will test the program to-night.
Ken

[mithrandir (Andrew)]

Originally Posted by troypiggo

Typo in your link. It should be http://www.stereopsis.com/flux/
I suspect you'll upset other astro buddies if you use this near them at a dark site, as it'll probably still be near-white light. Red light is much better at maintaining your night-vision.

I've seen some other reports on using red to preserve night vision. They concluded that the intensity probably matters more than the colour, and that white light is less tiring that red.

From 365 Days of Astronomy:
http://www.alicesastroinfo.com/2010/...-night-vision/
which has some reference links.

A discussion of dark adaption:
http://webvision.med.utah.edu/light_dark.html
For at least the first 10 minutes the colour does not appear to matter.

[noswonky (Peter)]

I use red light when observing - not because it's better, but to avoid having abuse hurled at me by other observers.

[solissydney (Ken)]

Very interesting information about the research on night vision using white and red lights
at night. Most informative I think.
But, most of you seemed to have missed the point of the information. The purpose of the posting was to make you all aware of the health danger from exposure to the blue wavelength light emitted from monitors. By reducing the light output from monitors of PC and unfiltered Laptops helps minimizing the circadian-disrupting blue light that is harmful to our health.
Ken

[multiweb (Marc)]

I also use red when imaging. Since I have got used to shielding my laptop screen with dark red perspex I have found that next, all the blue and green lights on the laptop leds themselves became irritating because when I do get my night vision every bit of green or blue led will hurt my eyes. Now I have everything red and it works for me. I wouldn't go back to staring at a white laptop screen again. I don't even need a red light to go around anymore unless it's cloudy

[troypiggo (Troy)]

Sorry, I missed your point about health.

I've spent money getting monitor calibration tools, so I'm not going to stuff all that up by using a program that adjusts the display. Sorry.

Why red light for nightvision? From Wikipedia:

In biological night vision, molecules of rhodopsin in the rods of the eye undergo a change in shape as they absorb light. Rhodopsin is the chemical that allows night-vision, and is extremely sensitive to light. Exposed to a spectrum of light, the pigment immediately bleaches, and it takes about 30 minutes to regenerate fully, but most of the adaptation occurs within the first five or ten minutes in the dark. Rhodopsin in the human rods is less sensitive to the longer red wavelengths of light, so many people use red light to help preserve night vision as it only slowly depletes the eye's rhodopsin stores in the rods and instead is viewed by the cones.

[solissydney (Ken)]

Same here. Any glare spot, including LED's when viewing is a nuisance. And that includes the green light from my digital clock in my vehicle at night. A dab of black paint on the LED's goes a long way in dimming them
Ken