Re: the ultimate refrierator

Hara Ra (
Sun, 21 Dec 1997 23:42:42 -0800

John K Clark wrote:
> On Sun, 21 Dec 1997 Hara Ra <> Wrote:
> >At the focus of the telescope, with a really low f-ratio, the sky
> >will be seen to be mostly the black hole.

> The lower the f-ratio the shallower the depth of focus, that is, the more
> nonlinear it becomes. This fact is of some importance when dealing with real
> light sources that are not mathematical points.
We don't need a focused image, just that the rays intersect the event

> I haven't worked out the calculation but my intuition tells me that you'd do
> better to forget about the huge ellipsoid and just make your heat radiator
> bigger. It's true that a light beam passing through one focus of an ellipsoid
> will pass through the other focus too, but it's not necessarily true that a
> light beam that passes near one focus will pass near the other one too.
In order to have a continuous image, you must have continuity of
adjacent rays.

> It's a little off the subject but this reminds me of something I read a few
> years ago about a man who made elliptical pool tables rather than the more
> traditional rectangular ones. They were not very popular. The trouble was
> that skilled professional players were not much better than rank amateurs at
> the game. Chaos took over and nobody had any idea where the billiard balls
> would end up when a shot was made. Skill plays no part when a elliptical
> table is used, it turns the game into one of chance.

I suspect a circular table would be more playable.

Years ago we tried a superball. (the first superballs were about the
size of pool balls) What a joke...

| Hara Ra <> |
| Box 8334 Santa Cruz, CA 95061 |