Transparent red screen filter for smartphones

[ismangil]

Anyone know UK supplier for these kind of screen protector?

http://www.astrogizm...TransVinyl1.htm

[Carbon Brush]

Sorry can't help there. But it looks an interesting product.

I would certainly try one if it was available from a UK supplier. But the prospect of Royal Mail making a meal of the import and ripping me off is too much to tolerate.

[acey]

I don't know if any laboratory studies have ever been done, but I should think that staring directly at any kind of extended light source, red-filtered or otherwise, is going to spoil dark adaptation. Your eyes will quickly adapt to the brightness level of the screen, and even a dim screen is a lot brighter than even a light-polluted sky. The other night I turned on my mobile after a long observing session and it literally hurt my eyes. No problem, of course, if you're only imaging, in which case you don't really need to do any kind of filtering of light-emitting equipment, unless it's to save the night-vision of visual observers nearby. But if you think it's worth screening the phone then red lighting gel (e.g. Lee Filters) is cheap and would do it. There's also the red acetate that people stick on computer screens - someone else will remember the name. The other general advice is to magnify things as much as possible, either with screen settings or a magnifying glass, because then you will be able to read at a lower contrast level. The phone might not go sufficiently faint, in which case you would need lots of layers of red acetate. The test of any kind of light is to look through the telescope at a very faint object, expose yourself to the light source e.g. while note-taking, or in this case looking at the phone, then look through the telescope again, and see how long it takes for the object to reappear. Ideally it should take no time at all.

[acey]

Out of interest I did a quick google on smartphone screen brightness. Apparently the typical figure is 200-550cd/m² (http://www.ximix.biz/smartphone-buying-guide/hardware-overview). By comparison, a sky with a limiting magnitude of 5.5 has a luminance of about 0.001cd/m2 (http://www.unihedron.com/projects/darksky/NELM2BCalc.html and http://www.unihedron.com/projects/darksky/magconv.php). So a smartphone screen is about 200,000 times brighter than a reasonably dark sky.

[ismangil]

This more for the benefit of others I suppose so as not have a beacon, because even though some apps have night mode, the home screen doesn't...

On mobile (excuse the strange predictive words...)

[Rustmonkey]

I'm getting some acetate type stuff delivered next week. Gonna try it on both my phone and iPad. If it works and I have some left I'll give it you at PSP12.

[goolosh]

I have an Android, i use a program called "Night Mode" which will take the brightness so far below the phones allowable settings you can barely see it in daytime. Makes it ridiculously dim down to like 13% of the brightness when fully dimmed by the phone, combine that with "SkEye" (astronomy app) which has a built in "Night Mode" which makes everything Red.

[acey]

Name I was trying to remember - Rubylith. Often used for covering computer screens, apparently.

[Stu]

Thanks goolosh, that is a great app! Will try it properly next time I go out but it seems to work very well. Certainly in my back garden where I don't get fully dark adapted, it might make phone apps useable

Cheers

Stu