The is single handedly the best ventriloquism I have ever seen for an intro.
@ccaissie113
3 жыл бұрын
The title is "bronze", but are you in fact using traditional Speculum?
@Erik-rp1hi
4 жыл бұрын
How do you put the concave surface in the disc?
@NAUT758
4 жыл бұрын
Answers we can't get😭
@georgioskoronis4433
3 жыл бұрын
Search telescope mirror making on google you will find hundreds of sites.
@maximohuenulef
Жыл бұрын
Grinding for hours get a concave Surface.
@pavichtv.4942
3 жыл бұрын
Dang
@ADRIAN-zh4ti
8 ай бұрын
I think aluminium would be better
@georgioskoronis4433
3 жыл бұрын
Interesting only for historical reasons. Bronze and the similar speculum metal tarnishes quickly and you have to regrind the mirror. After glass silvering was invented the metal telescope mirrors became obsolete.
@purvel
Жыл бұрын
It is much easier to cast and polish speculum/bronze for the hobbyist than slumping, grinding and silver coating glass. Bronze keeps fine if you take care of it, and all it takes is a light polish to shine again.
@marianl8718
Жыл бұрын
@BB Sky Long before the appearance of this video I also polished some bronze mirrors, but much smaller. When bronze has a high concentration of tin, around 30%, it is very hard (its hardness exceeds the hardness of steel) and very brittle (it breaks much easier than glass). Being so hard, it can be polished perfectly ! Aluminum cannot be polished because it is too soft, although there are alloys of aluminum that could be polished, but not as well as bronze. Bronze mirrors reflect about 70% from light.
@marianl8718
Жыл бұрын
@BB Sky The too hardness of bronze should not worry, because it is also fragile and brittle and can be processed in much the same way as glass. I also tried to polish a bronze mirror of only 42 mm diameter with which I made a Newton telescope. I had many difficulties, because I don't have too many material possibilities. I melted the bronze with the stove and a Bunsen burner, and you can't melt too much with something like that, but it was enough. The other disc can be from iron or brass. Although the formation of the concavity of mirror is done in the same way as in the case of glass mirrors, the polishing proceeds differently, not as shown here ! That's exactly why we weren't show the result of the polishing, because I'm sure it didn't turn out very well ! I used chromium oxide, and the polishing followed the same method indicated by Newton in his book "Optics". In relation to this subject, I wrote a very detailed article, of 9 pages, in an astronomy magazine from Romania, where I am from. This video deals with an extremely important topic and it has so few views ! The topic is related to the history of astronomy, to Newton and Herschel !
@maximohuenulef
Жыл бұрын
@@marianl8718 melting on bunsen burner??? Is impossible!!
@marianl8718
Жыл бұрын
@@maximohuenulef It depends on the quantity. A bronze with 30-32% Sn melts at around 750-800°C, and the temperature at the top of the flame of a Bunsen burner, with a concentred and strong flame, reaches 1700°C (nitrogen in the air does not contribute to combustion and cools the flame). I also helped myself to a stove eye that was burning underneath, and on top of the metal I came up with the flame of the burner, which did the hardes part. At that time, propane-butane burners were not commercially available, which are very good, but their fuel tank is quickly depleted.
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