program diet sehat how to lose 40 pounds in 2 months: Big Bertha In Daylight

Minggu, 02 Juni 2013

Big Bertha In Daylight

Big Bertha in previous incarnations has never worked out terribly well in daylight because of the open tube structure; stray light is always going to be a problem.  I was therefore at first unsurprised when I used it to look at the television towers on top of Big Basin (which is a number of miles away) this afternoon.  But even at 222x, I was quite pleased with the optical quality.  Now, if only it gets dark to see something before I have to go to bed!

During church this morning, I suddenly realized a solution to a problem that has been bothering me about making hexagonal telescope rings to hold Big Bertha to the mount.  It would be impossible to use this metal brake that I have to bend 1/4" aluminum -- but 1/8" thick aluminum is probably too flexible.  But what I bent 1/8" aluminum into the inner part of the lower half of the hexagon, and another 1/8" thick piece to be effectively the outer layer of the hexagon?  Then bolt them together at the vertices of the hexagon, so that I get most of the stiffness of a 1/4" thick ring, with the ease of construction of the thinner pieces?  Even better, I have a large sheet of 1/8" thick aluminum that I could use for this purpose.

I have therefore been experimenting with making a small set of hexagonal telescope rings (like about 2" across) just to get some practice at making them on a small scale first.  And yes, 1/8" thick rings feel stiff enough, but because of the square/cube law, they almost certainly would not be stiff enough for the size that I need for Big Bertha.

I feel the need for a metal shear, but by the time I see the cost and size, I will probably just go to my friendly metal store and pay them to use their shear instead.  The bandsaw that I have just doesn't do that good a job on metal (it is really a woodworking tool), and cutting small slices with the chopsaw is impractical.

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