What would be some examples of high powered eyepieces?

Answer 1

A microscope, a telescope, etc.

Answer 2

Any very short focal length eyepiece. Magnification is objective focal length divided by eyepiece focal length. My highest power eyepiece has a focal length of 4mm, which gives me 300 power. I almost never use it. I prefer the 6mm, which gives me 200 power. That is about right for my 6 inch telescope if the atmosphere is very steady. The image is reasonably sharp and bright. The 300 power eyepiece just makes an image that is too dim and blurry.

You can also increase magnification with a Barlow lens, which is used in combination with an eyepiece. It effectively increases the objective focal length.

Answer 3

In addition to the other answers given, let me say that if you are still getting a dobsonian you should get some experience using the eyepieces that come with it before you invest in others -- although getting a Barlow lens is definitely recommended. More often than not you will be using lower powers, and in most locales the instability of air columns will not let you push the scope to its theoretical magnification limits except on exceptionally rare nights. Check to see that the stars aren't twinkling (much).

Here is a 10 second video I took of a part of the moon recently. This was on a night of better than average seeing but was getting worse at the point the video was made, at about 300x (with a driven 8" scope). Notice the rippling and distortion in the image -- it gets a lot worse when you increase the magnification, and harder to track without a motor as well because it will move out the field of view quicker when you use higher magnifications. Again this was on a driven telescope (not a dob).
http://s17.photobucket.com/albums/b83/urban-astronomer/moon-sept/videos/?action=view¤t=MVI_1341.flv

Answer 4

On most amateur telescopes, magnification of 25 to 50x per inch can be considered the "high power" range. More than 50x and you start just magnifying the blur. Unsteady atmosphere may limit you to even less, especially with a large telescope.

You can select your eyepieces based on the focal ratio of your telescope. An eyepiece whose focal length in millimeters is equal to the focal ratio will give you 25x per inch, and one half that length will give you 50x per inch. So if you have an f/8 telescope, a 4mm eyepiece would be about the limit.

Answer 5

they are probably looking for magnification, e.g. "100x" or "250x". This is a poor question absent the proper context.

The above answer is correct in part. A shorter eyepiece is indeed more powerful on a telescope. however, there IS a 'theoretical imit of magnification" which is derived from the known frequenciy of light, though I don't recall how to calculate it.

Answer 6

Using telescopes as an example, one increases or decreases the magnification of a particular telescope by changing an eye piece.

General rule of thumb: If the number on an eyepice (actually its "focal length") gets bigger, magnification gets smaller. As the number (focal length) of an eye piece gets smaller, magnification increases.

Total magnification is a function of the focal length of the eye piece and the focal length of the instrument in which it is installed. As an example, my main telescope has a focal lenth of 2500mm (2.5 meters, about 8 feet). Total magnification is found by dividing the focal length of the telescope by the focal length of the eye piece.

Thus (on my telescope) an eye pice with a focal length of 25mm results in a magnification of 100x. (2500/25=100) A 50mm ep gives me 50x (2500/50=50). A 4mm ep gives me 625x (2500/4=625).

With telescopes it is important that ANY magnification is THEORETICALLY possible, but really big numbers are generally not PRACTICAL. On my telescope, which is 10" in diameter, 625x magnification is WAY too much. On a perfect night, under perfect skies MAYBE I can push it to 500x, but realistically, here in Minnesota, anything beyond 350-400X is never practical.

Answer 7

Telescope.