Far-Sight-Glass

A Far Sight Glass makes things look bigger when you look through it. It isn't always made of glass. Some old ones are made of metal, and if you don't pay a lot for one, you might get one made of plastic.
There are three kinds. One kind uses bent glass mirrors, the other uses clear bent glass that you see through. The third kind uses mirrors and clear glass together, so you can spend less money on the mirror and you can fix the image with the clear bent glass.

Far sight glasses work by using a mirror or clear glass which takes a lot of light and brings it together to a point. But you can't see light that's come together to a point, because of the way your eye works. So we use a small clear glass, that brings light together at a closer point than the main mirror or clear glass, to make the light lines go side by side instead of coming together. Distance of light coming together of the main mirror or clear glass, over the distance of light coming together of the small clear glass, gives you the number of how much bigger a thing appears in a far sight glass. In most far sight glasses, you can change the small clear glass to one with a different together-distance to change how big things look.

The Far Sight Glass was made by children in around 1600, but a guy who made eye glasses made his own and said he made it first, so he could get money for it. He couldn't get the papers that said he could get money for it, but the country's war team bought a lot of them anyway. These Far Sight Glasses used clear glass instead of mirrors.

In 1608, someone else in a different country heard of the Far Sight Glass and wanted to make his own, so he could make it look like the Moon and the stars were closer. He also sold far sight glasses to his country's war team, but he mostly cared about looking at the sky. When he looked at the Moon, he saw that it was not a perfect, round ball, but it had holes and mountains like the Earth. Until then, everyone (especially the church) said everything in the sky was a perfect round ball. He also looked at one of the stars which move from night to night, and found that it had four little stars which move around it. Almost everyone (especially the church) before then thought that Earth was the center of the whole entire everything, and the Sun and moving stars and fixed stars all moved around it. But this guy found that there were four stars which went around one of the moving stars instead of around the Earth. He also found that cloud-like stars were actually lots of tiny stars close together, and so was the white path of cloud-like stars in the sky. He found that there were many more stars seen through a Far Sight Glass than could be seen with just your eye. And he saw that the shadows of one of the moving stars only made sense if it went around the Sun, which also showed that Earth could not be the center of everything.

Since it was first used, the Far Sight Glass has been the main thing that sky watch people have used to study the night sky (and the sun). One of the problems with a far sight glass is it shows a lot of color on the edges of things seen through it, because glass takes white light and breaks it into its colors. Early sky watch people had a lot of problems with this, because to fix the problem you need a very long far sight glass. The fix came from two new kinds of far sight glass.

The guy who found out how things everywhere move, also liked to play around with light and glasses. He thought a far-sight-glass that used a mirror instead of clear glass would not have color problems. So he made a far sight glass with a metal mirror. Even though his mirror was a piece of a ball instead of a more perfect bent shape, he was able to show that his far sight mirror had no color problems. The problem was, the images in the metal mirrors were not as bright as what you'd see through a clear glass of the same size, so the metal mirrors had to be made very wide.

Another fix to the color problem came a bit later, when someone found out if you use two kinds of glass and make the main part of the far-sight-glass out of two thinner glasses, the color problem would be mostly fixed. (Much later people realized that three or four different kinds of glass could fix the color problem completely.) Such far-sight-glasses are called no-color-glasses. (the three or four glass ones were called farther-from-color-glasses.)

Far-Sight-Glasses have to be put on a stand that lets it point anywhere in the sky. You can't make images very big if you have to hold the far-sight-glass in your hand. The simplest kind of stand is an up, down, and all-around stand, which is enough to point the glass and see things without shaking. But because the Earth is spinning, the sky moves, so you have to keep moving the glass on the stand to keep up with the spinning. To make this easier, some stands are pointed at the north star, so that one of the directions the glass moves is the same direction as the earth's spin (east and west), and the other direction goes north and south. If you put a time-watch-drive on the east/west direction, it will keep up with the Earth's spin for you.

Around 1850, people started to use cameras, and sky-watching people were not far behind. It wasn't long before we had pictures of the Moon that looked good, and cameras started to be used instead of eyes for serious sky watching. A picture could be made for a long time, which would gather more light and show dark things like space clouds and star groups more clearly. Using a far-sight-glass with a camera means you need a stand that is pointed at the north star and has a time-watch-drive. (Though it is possible to make do with using a computer and an up-down-drive and all-around-drive stand, which is what almost all serious huge far-sight-glasses use these days, because it's easier to build than a huge north-star stand.)

Later, people (mostly the sky-watch-people doing sky-watching for fun instead of being paid to do it) started to break up the light from space things into its colors (but they meant to do it this time) so they could see what is the same and what is different between space things and things we know the colors of on Earth. People used to think the Sun was made of rock and metal just like the Earth, but when they started pointing their color-breakers at the Sun and Stars, they found that it was made of a sort of air that was never seen before. It was later found on Earth, and we use that kind of air to fill flying air-bags at parties. The name for that kind of air is "sun-stuff," in fact. What's more, the Sun and the stars were made of the same stuff!

The sky-watching-for-fun people did such a good job that the serious sky-watching people started doing studies with color-breakers, because it became possible to do serious work with figuring out how everything in the sky works, not just how it all moves. Before then, most serious sky-watch-people were paid to just look at how things moved, how far away everything is, and not so much with the "how" and "why." Now almost all serious sky-watching is about the "how" and "why."

Around 1900, it became possible to make mirrors out of glass and cover them in a thin layer of very bright metal, which would be almost as bright as using clear glass. These mirrors could be made much bigger than clear glasses, so when someone wanted to make a huge Far-Sight-Glass, they'd use a big metal-covered glass mirror. Now, almost all far-sight-glasses used for serious sky-watching for the people whose job it is to do sky-watching, use mirrors. All such serious sky-watching is also done now with computer-cameras.

Some huge far sight glasses have travelled into space on up-goers, and some have flown on winged flying machines. The air of the earth blocks some kinds of light (light which your eyes can't see), so if you can go above it, you can see those kinds of light. Also, the air of the earth is never perfect and still, it shakes around, so you can't get very big close up pictures of the other worlds in the sky unless you use computer-cameras and you're lucky. If you go above the air, you don't need to be lucky and it's easier to get good pictures.

Sky-watching-for-fun remains a fun and cool thing to do and lots of people around the world do it, with far-sight-glasses small and large. The best kind of for-fun Far-Sight-Glass is was first made well-known by a man who worked at a church (but not the kind that loves the son of god, the kind that thinks everyone gets born again after they die), but was fired from the church for making too many far-sight-glasses. His far-sight-glass used a big glass mirror that he ground into an almost perfect shape himself, with the long round box resting in a box that goes up, down, and all around. They were easy to make and you didn't have to pay much to make them, and they are very easy to use and give very good bright images. Now though, you can buy a far-sight-glass of this kind for less money than it would take to make one. If you want to buy a far-sight-glass, but you don't have a lot of money, maybe you should get a special kind of far-sight-glass which is two small ones stuck together, doesn't make the picture very big, and is held in your hand. They're a good way of getting to know the star groups and some of the cloud-like things. When getting a far-sight-glass, be careful not to get a "less-money store clear-glass" or "fun-time-killer clear-glass." Make sure the stand is very strong and won't shake, and that the main clear-glass is wide enough that 5 or fewer of them in a line would be longer than a foot.