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Originally Posted by Stephen H It's hard to get a good grasp of what they did know.
I remember reading long ago that the Caesarean Section was called that because it was supposed to be how Julius Caesar was delivered. But it's hard to imagine the ancients doing that and both mother and baby surviving.
Working out the planetary details I don't see as being that challenging- I think other ancient cultures did as well. The challenging part is really keeping records for long enough to make useful observations. I've seen lunar eclipses, you've probably seen them, but we sure didn't mark it down on the calendar when it happened.
I think it's interesting how the guy speaks of this one-and-only ancient doohickey. Like some ancient Greek got up one morning, made one, and never thought to do it again. If they made one, different people are bound to have made a bunch of 'em at different times and places (and of different complexity and expense). Having to hand-cut the gears would be a major slowdown in the production. But if theypieces are delicate, they wouldn't survive well, and if made of brass, it could always be melted into something else when it wore out.
Someone mentioned pinhole cameras up there. You can make homemade "film" and pinhole cameras, but the two are not a good mix. It helps to have reasonably fast film OR an actual lens. Recall in the old days, people had to sit for a minute or more to make a portrait- even used neck braces and stuff to accomplish that.
As far as I know, the ancients never had plate glass as a common item, which puts a damper in some forms of photography. |
In reference to the machine who is to say that it wasn't made for the high priests which means it could be a one of a kind in it's final form. (we are not talking about a tool used by the average joe). As to working out the details of the planets locations for times in the past and future and converting that into a mechanical devise that can predict the locations later is a huge leap.
You have fallen into the slow film thing, those portrait sessions that had the person stay still were generally under 30 seconds and indoors with some sunlight coming in and if they wanted a rock solid sharp picture the person had to stay still for the 30 seconds hence the brace.
http://www.photo.net/history/timeline
Heck by 1877 film was fast enough to prove a horse when galloping had all 4 hooves off the ground at once.
If you go back and look at some of Brady's Civil War shots, een though he was shooting mostly dead people after battles or munitions/cannon set ups his exposures were under 10 seconds outdoors and many were in the 1 second range. Also a bit later there were a lot of photographers who would travel around the country using wet plate processes and shoot workers in the field and the people and even animals would be sharply in focus which indicates rather fast exposures. (also why would late 1860's era lenses have exposure times on their shutters down to 125th of a second or faster?)
http://www.cwriley.com/photica/shutters.htm 1/300th sec in 1880's So film had to be sensitive enough to handle this speed of shutter along with a f 4 lense speed-many lenses at this time were in the f8 or slower range and of course many of the large format lenses were stoppable down to f32 or f64. So logically the film had to be fast enough to take a shot at f4 1/300th of a seond back in the late 1880's.
Also we are not talking about common items! We are talking about something that would have been done for the ruler of the country or a handful of scientists. Having single glass plates of 4x4 inches would not have been past their ability at the time, now having them last for1,000 years is a big diference! Also having them not become opaque over time is a limit also.
So I still would not be suprised if they found some reference to what we call photography back from that time period though we may neve see a "photograph" from the time period.
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