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Comment Re:Oh christ... (Score 1) 510

I think you are narrowing in on the problem of free healthcare. You needed two vists to doctors before the age of 18. I assume that you didn't develop any life altering diseases in that time. Question, if you would have have a proper free healthcare plan, how many un-necessary visits to the doctor or procedures would you or your parents have used. Whenever you hide the true price of something that something tends to get overused and the resources get allocated improperly.

Comment Re:Not a Lens (Score 2) 101

No not really the same thing at all. Both strategies will form an image but the physics are different. The mirror reflects the light via a paraboloid and thus forms the image without any chromatic abberation. For the lens to form an image the light must pass through the glass and because the speed of light in the glass depends on the wavelenght, the refractive index is slightly different for every wavelenght and the therefore the lens will show significant chromatic abberation. This is assuming that it is a single lens. Multiple element lens are possible to design with different refractive indicies that will minimize this effect but they are much more complex and expensive. Oh by the way the largest refractor ever built is the Yerkes telescope which is only 40" in diameter. Anything larger would distort under it's own weight.

Comment Re:Isn't there even one picture through it? (Score 2) 101

Even with tracking capability, which isn't that hard for a dobsonion, alta-azimuth mounts like this suffer from field rotation effects and exposures longer than about 30 seconds are not ideal. But you can take many 30 second exposures and stack them to give you something resembling a much longer exposure. The stacking de-rotates the images and aligns them.

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