D254f1375 Refractive Lens For Astronomical Telescope

13 Comments

1. cerk says:

   March 22, 2010 at 12:41 am

   It sounds like you have one of these:

   It hasa 60mm objective, a 700mm focal length, and comes with 4mm, 12.5mm, and 20mm eyepieces. Lets begin by putting aside the barlow lens and the erecting lens. The erecting lens works best for terristial viewing and the barlow lens is not needed on this size scope.

   Begin viewing with the 20mm eyepiece (35x), and find and center your target. Adjust the focus so that it is as sharp as you can get it. Now watch the object move across your field of view. Try adjusting your scope to keep ot right in the center. Once you get comfortable doing that replace the 20mm eyepiece with the 12.5mm eyepiece (56x). Notice that the object seems to be moving faster, it is much harder to keep it centered. But, learn to do so and practice until you are comfortable.

   Finally replace the eyepiece with the 4mm lens. This should take your magnification up to 140x. Try to sharpen the image, but be aware that 140x may be too much for your scope or too much for prevailing conditions. If it is not really sharp then go back to the 12.5 eyepiece.
2. hachaan blakebess says:

   March 23, 2010 at 5:41 am

   The image projected at the focal plane will be 3 times larger in telescope A. Through the eyepiece, you will get identical images if you use an eyepiece in telescope B with 1/3 the focal length of the one in A.
3. peachoody says:

   March 25, 2010 at 9:41 am

   They wanted to build a waveguide, a structure designed to send light in a particular direction, by drilling carefully spaced holes in a gallium arsenide crystal. Because the crystal bends light much more strongly than air does, light should have bounced off the holes and traveled down a channel that had been left clear of holes.

   In some cases, the light refused to move. It kept getting stuck inside the crystal.

   “At first we were scratching our heads,” Lodahl says. “Then we realized it was related to imperfections in our structures.” If imperfect materials could trap light, Lodahl thought, then physicists could couple light and matter with much less frustration. [The momentum of the photons being absorbed by the imperfections ala negative refractive index metamaterials?]
4. jolek says:

   March 27, 2010 at 6:11 pm

   fbueno123, are you thinking of thermal cycling? I agree. The temperature difference would make the cold fall, but the path up would have to be pretty vertical and clear for good motion. And have mercy if he simply roughed up the copper and put a light captivating coating on it. He’s losing a GREAT percentage of energy through reflection. informative presentation, thank you.
5. matthy says:

   March 28, 2010 at 2:37 am

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6. saka says:

   March 28, 2010 at 3:08 am

   Yes, technically you can move it manually, but there is no slow motion controls or anything like that that would allow you to utilize it as a true “manual” telescope.
7. zen says:

   March 31, 2010 at 7:55 am

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8. ron says:

   April 6, 2010 at 12:09 am

   so a baby is bad when god kills it in an earthquake?