Never ignore the small ideas that nag and tickle and refuse to go away, for in them lay the seeds of destiny.
- From "Babe, The Sheep Pig"
Chuck's discussion on cold-molded tubes put me in mind of and idea I had awhile back. Perhaps it has been kicked around, and rejected, since 1924, but I will bring it up anyway. What about an inflatable telescope tube?
Just a minute to explain, please, before giggling. A number of everyday objects exhibit both light weight and rigidity through internal pressure. The aluminum soda can is an example: barely thicker than foil, but still extremely rigid when pressurized. You would need a material with high tensile strength and low elasticity. Aside from metal foil, a stiff plastic like mylar could do the trick. I picture a double-walled cylinder with a series of internal ribs to prevent bloating. A heavier ring at both ends would provide mounting locations for optics. It would need to be air-tight, but this doesn't seem to be a problem for basketballs and tires (except my left-front, which is always going flat). I can easily picture an ultra travel scope: take it to the beach an blow it up there!
A less radical plan would be a thin dual-walled cylinder filled with pressurized foam. Perhaps not as light, but it wouldn't require an air pump to go with one's eyepeices.
What say you? Has anyone tried any of these? I can vividly imagine a long series of frustrating experiments, accompanied by hissing noises, before the final triumphal success.
Best Regards,
Gary Hansen
- From "Babe, The Sheep Pig"
Chuck's discussion on cold-molded tubes put me in mind of and idea I had awhile back. Perhaps it has been kicked around, and rejected, since 1924, but I will bring it up anyway. What about an inflatable telescope tube?
Just a minute to explain, please, before giggling. A number of everyday objects exhibit both light weight and rigidity through internal pressure. The aluminum soda can is an example: barely thicker than foil, but still extremely rigid when pressurized. You would need a material with high tensile strength and low elasticity. Aside from metal foil, a stiff plastic like mylar could do the trick. I picture a double-walled cylinder with a series of internal ribs to prevent bloating. A heavier ring at both ends would provide mounting locations for optics. It would need to be air-tight, but this doesn't seem to be a problem for basketballs and tires (except my left-front, which is always going flat). I can easily picture an ultra travel scope: take it to the beach an blow it up there!
A less radical plan would be a thin dual-walled cylinder filled with pressurized foam. Perhaps not as light, but it wouldn't require an air pump to go with one's eyepeices.
What say you? Has anyone tried any of these? I can vividly imagine a long series of frustrating experiments, accompanied by hissing noises, before the final triumphal success.
Best Regards,
Gary Hansen
