If you haven't seen it already, I'd highly recommend the Netflix series "The Heavy Water War" (trailer: https://www.youtube.com/watch?v=_K3Ry2K4yNE)
It was strange, but also really odd when it felt like the sun would go down so early as it crossed behind the mountains.
But that is where the sky is supposed to be! ;)
I'd say they are pretty similar, Coelux may be slightly less diffusive but it's beam divergence angle is pretty high so it doesn't hold up for very much distance compared to ours - you can see it spreads out into a non-rectangular shape on the wall.
I'd probably shine an array of narrow-beam LEDs through a sheet of aerogel. (the aerogel disperses the blue light) If the LEDs are on long horizontal rods that can rotate, that lets the angle change. You'd need the beams focused down to about half a degree, with at least a dozen viewed in a circle of that size from the perspective of a tall person under the light.
Another way is just an RGB array, with different lenses on the different colors. The blue gets a fish-eye lens, while the green and red get focused down to about half a degree. Again there can be rods that rotate, and at least a dozen LEDs need to be in a circle of half a degree when viewed by a tall person under the light.
edit: oops! I read “it ours” as “ours it” somehow!
here is a direct link so people don't have to copy/paste https://innerscene.com/products
I was excited for a while there, but I guess I'll continue on my path to becoming Gollum
Why yes, please take these black plastic balls, coat them in a known carcinogen, place them over drinking water, and let them bake over the sun.
The entire shade-ball program was created to mitigate high levels of bromate which were forming when sunlight interacted with chlorinated water. Bromate is an _actual_ carcinogen; as opposed to the carbon black coating on the shade-balls which is only carcinogenic when inhaled as dust (otherwise the activated charcoal in all those drinking filters would be pretty bad news).
One-time use plastic bags and more recently drinking straws, not all plastic everywhere. The world can’t run without plastic.
Your own link says the recycleable (fwiw) balls have a 10 year lifespan.
...and the carbon black is a carcinogen if inhaled as dust, but is used (in part) to reduce a suspected carcinogen (bromate) and made for the sun (...with carbon black additive to protect the plastic from ultraviolet radiation.)
It’s in your cited article. What would you propose as an alternative?
That's actually the opposite of what's going on. From wikipedia:
Starting in mid-2008, the Los Angeles Department of Water and Power (LADWP) deployed around 400,000 balls in the Ivanhoe reservoir with the main objective of preventing the formation of a carcinogenic chemical, bromate, which forms when naturally occurring bromine reacts with chlorine in the presence of sunlight.
The black coating on the balls, called carbon black, is a petroleum derivative which is classified as a carcinogen if inhaled as dust. ”
So you have balls made with a known carcinogen (if inhaled as dust) to prevent formation of another carcinogen formed in water. I’m guessing they researched the risks already and it’s a net positive.
Only a couple of hours drive from Oslo.
In case you need an excuse to visit.
Actually, things are not as bad as in Seattle/SF/LA/New York, but modest things are still very expensive in our cities.
Just googling, $2,000 gets you 1300 watts of heat. Or 115,000 lumens. (100 watt incandescent is 1600 lumens). The mirror part is about 4 feet x 4 feet.
In English there isn't a general word for altering a trajectory into an object. In this case however, reflect is precisely suited to what mirrors do to light and doesn't have the confusing inverse connotation of away. You reflect away from something or onto something equally well in English.
yay for the elegance of latin-based prefixes! =)
In a neat coincidence "umbrage" and "umbrella"
apparently share a common origin in Latin "umbra" (shade).
(The purpose is just curiosity. Reposts of a story are ok after about a year, as the FAQ explains: https://news.ycombinator.com/newsfaq.html.)
2 36000 tan(0.25 deg) = 314 km
But can't find any good design/plans for DIY or anyone selling one.
I have the vacuum mirror focusing upgrade pack.
Works really well and I roughly calculate that you get 80% of the growing power from the sun as direct light.
I use it for a part of the garden that never got light due to building and trees and was always soggy and damp. Nothing grew there very long, now I maintain native wildflowers and a butterfly garden there.
It’s really cool. The heliostat follows the sun mechanically and also can tune in the focus with a vacuum system.
They said a lot of interesting things in this article related to the sun, so I leared some new things. At the same time I am surprised about some things they did not say.
I'm not an authority on the bodies need for sun, but I will give my non-scientifci observations. If some one finds this interesting they should do some additional research on the topic before they do anything I did, rather than just trust what I write here.
One thing that really interested me was an article I saw here on Hacker News a several months ago. It said it is well known people with higher vitamin D levels had some health bvenefits. However, one particular study found that giving vitiamin D supplements did not seem to give the same health benefits. The authors concluded from their results that people who have high vitamin D often get this from the sun, and the sun gives them a different result from just taking vitamin D supplements.
I tried going to a sun tanning salon and found that did make me feel a subtle "high", as if I had been out on a sunny day. (Your experience may very.) From what I understand it is UVB that is responsible for this, the "bad" UV. It is considered bad because your body does not shield against it and it does not cause you to tan.
General tanning salons want to give you UVA. The expensive machines limit your UVB exposure, and the cheaper ones give you more UVB (salons often have different options for beds). You want to go to the cheaper option. I used beds at tswo salons with 5% and 6% UVB, for reference. They should know the UVA/B statistics for the machines.
As far as length of time, you don't need to go that long. The point is not to get a tan necessarily. I found that i would get more tired if I stayed in too long, so there is sort of an optimal time, for me at least. (I am very pale, by the way.)
I also noticed that the sun tanning bed was not enough. It is almost as if there are two effects. I feel good from the tanning salon, but at the same time it feels like there is something missing. I also need to go outside, I assume to get visible light.
To repeat above, these are not scientific results. I find this seems to work for me, and that is good enough. I would not suggest someone trust what I say here as authoritative, but hopefully it can be an inspiration to look into this if you have similar problems.
FYI, one thing I want to look into as a result of this article is timing of getting visible light. I do know that if I wake up in pitch black I have trouble getting out of bed. I would link to get more bright light in the morning right when I wake up and see how that effects me.
Deflect means to shield an area from sun; this project is to bring sunlight into a perpetually shaded area.
Definition of reflect
1 : to prevent passage of and cause to change direction
// a mirror reflects light
Definition of deflect
: to turn (something) aside especially from a straight course or fixed direction
// armor that deflects bullets, deflecting a question
With deflect, something is simply being diverted, whereas with reflect, it's more intentionally being aimed somewhere. This is the nuance I feel innately, although at this point we're splitting hairs I think.
Deflection is typically used when the would-be target is protected from the incoming object. Reflection is when the never-was target is now a target.
I don't see why deflect isn't acceptable. Previously the sun was shining on the hillside below, now it's been deflected to the town square.