Looking for methods to preserve night vision

Question

Does anyone have a method to preserve night vision so that a car or other passing light source does not ruin it?

I have a dark location to observe the sky; however, it is near a rarely used dirt road. I can hear a car coming in time to protect my night vision, but have been unable to find a method so that its light does not ruin my light vision. I have tried putting a 5-gallon metal bucket over my head, covering my eyes with a towel, etc. My night vision still gets ruined.

I want to be able to totally block all light from my eyes until the car/light-source passes.

Answer 1

Your problems with shielding your eyes from light probably come because it is easy to shield them from direct light from the car lights, but hard to shield them from reflected car light coming from every angle.

1. I suggest that you experiment with closeing your eyelids while shining lights at your face.

I just tried shutting my eyes while looking at a light about a foot and a half from my face. Everything looked a very dark grey or black color, and it didn't look any brighter when I looked at the light bulb.

I often close my eyes when a passenger in a car and facing toward bright sunlight. The sunlight shines red through my eyelids and I tend to see geometric patterns - when the car passes into shade from trees the color changes to blue. So the geometric patterns sometimes flash between a red and a blue background rapidly.

But looking at the light bulb right now I don't see any light shining through my eyelids, because sunlight is many times as intense as the light bulb.

So possibly you might want to experiment with staring at lights of varying intensity with you eyes closed to see how much light, if any, penetrates your eyelids. And yu can try calculating how bright a car's lightswill be at your distance from the road, and comparing it to light sources which doo or do not penetrate your eyelids.

Maybe simply closing your eyes is enough to prevent loosing your night vision.

2. You could wear a helmet with a hinged opaque face plate that you can slam down when you hear a car coming. You could have opague cloth handing down several feet from the bottom of the helmet to prevent light from getting in through the bottom, or maybe tape the bottom of the helmet to your clothing.

3. If you own the place you observe from, you could built a tiny windowless shed or shack there and make certain it is pitch black inside with the door closed, and run into it and close the door when you hear a car coming.

4. You could set up a tent made of totally opague fabric or plastic sheets, and when you hear a car coming jump into it and knock down the tent pole to collapse it on you. When the car passes, struggle to get out of the tent, perhaps by finding the tentpole and putting back up.

I hope you might find some of my suggestions useful.

Answer 2

Too long for a comment:

I am awed by the variety and ingenuity of solutions proposed in the previous answer! One potentially non-trivial strategy not mentioned is that closing one eye tightly can preserve night vision in that eye which may be sufficient for performing tasks that do not need both eyes.

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TL;DR: I wonder if a portable screen of opaque black/dark cloth rising from knee height to above head height, held up by light wooden/aluminium poles would suffice. I envisage such a screen able to be rolled up into a bundle for transporting it. Collapsible aluminium poles in sections held together by elastic cord, like some tent poles are, would seem ideal. The poles will need sharp 'feet' so as to stick firmly into the ground.

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I am seriously thinking of making such a thing because I do my star gazing/name-learning on a public park near my home which has roads on three sides of it with several T junctions and bends which cause headlights to shine across the wide open grassed area. I have found a spot where the trees around the edges of the park obscure most of the strong street lights but the frequent sweeps of headlights from the roads - and/or the really annoying lights from cars parked facing into the reserve area - need rapid evasive head turning and blinking.

I live in a suburb of Perth Western Australia and light polution in the late evening is such that, in "good" conditions, naked eye sight gives me not-quite 3 magnitude stars looking directly at them and a wee bit more if slightly to one side. For example Tejat versus Propus in Gemini. Atmospheric lensing (ie twinkling) can both help and hinder this of course and 8 x 30mm binoculars help very greatly, as long as I can relate the location of what they show to the nearest naked eye visible star.

I am thinking that such a screen will greatly limit light hitting my body, phone (held high, displaying Stellarium), or binoculars which otherwise reflects back onto my face and eyes.