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a telescope's magnification is calculated as the ratio of the focal length of the primary objective to the focal length of the eyepiece. Since a telescope is defined by the primary objective, this part of it is essentially unchangeable. Therefore, the way to increase magnification is to decrease the focal length of the eyepiece. For example, a 1000mm objective and a 25mm eyepiece yields a magnification of (1000/25) 40x. Changing the eyepiece to a 10mm eyepiece increases magnification to (1000/10) 100x.
The magnification of a telescope M is the the focal length of the objective Fo over the focal length of the eyepiece Fe so increasing the focal length of the objective increases the magnification. The magnification of a microscope M is approximately tube length L/Fo x 25/Fe. Therefore increasing the focal length of the objective reduces the magnification.
The magnification of the telescope image is(focal length of the objective) divided by (focal length of the eyepiece).The focal length of the objective is fixed.Decreasing the focal length of the eyepiece increases the magnification of the image.(But it also makes the image dimmer.)
The magnification, or power, at which a telescope is operating is a function of the focal length of the telescope's main (objective) lens (or primary mirror) and the focal length of the eyepiece employed.
No, you can change the magnification of the telescope by simply changing the eyepiece. The two most important powers of the telescope, light-gathering power and resolving power, depend on the diameter of the telescope, but it does not control the magnification.
The magnification of the telescope image is(focal length of the objective) divided by (focal length of the eyepiece).The focal length of the objective is fixed.Decreasing the focal length of the eyepiece increases the magnification of the image.(But it also makes the image dimmer.)
That's 80 power.
The magnification of a telescope is the ratio of the effective focal length of the objective to the focal length of the eyepiece. For example, a small telescope's objective may have a focal length of 800mm. When an eyepiece with a focal length of 25mm is used, the magnification is 800/25 = 32. The term "effective focal length" refers to the focal length of the objective as affected by any "focal extender". Many telescopes are designed to have a short total size, but high power, by "folding" the optical path. A mirror-type objective with a focal length of perhaps 800mm is coupled with a smaller curved mirror that intercepts the last 200mm and extends it to 800mm, a 4x extension, so that the effective focal length of that objective is 3200mm. Use that with a 25mm eyepiece and the magnification is 3200/25 = 128. By the way, if a telescope is smaller than you are, it is seldom much use to view using a magnification greater than 50 to 100. Most objects are best viewed at relatively low powers such as 30 or so.
For visual observation: Magnification = (Focal Length of Objective Lens) divided by (Focal Length of Eyepiece) (They have to be measured in the same units.) For prime-focus photography: (One focal-length of the Objective Lens on the film) = (one radian in the sky)
The focal length of a telescope is directly related to the magnification in that the longer the focal length, the more magnification you get from the telsceope. How the focal length of a telescope relates to the length of the telescope itself depends on the design of the telescope. In a refracting telescope, the focal length is approximately the length of the telescope. In a reflecting telescope, the focal length is roughly two time the length of the telescope.
The magnification of a telescope is the ratio of the effective focal length of the objective to the focal length of the eyepiece. For example, a small telescope's objective may have a focal length of 800mm. When an eyepiece with a focal length of 25mm is used, the magnification is 800/25 = 32. The term "effective focal length" refers to the focal length of the objective as affected by any "focal extender". Many telescopes are designed to have a short total size, but high power, by "folding" the optical path. A mirror-type objective with a focal length of perhaps 800mm is coupled with a smaller curved mirror that intercepts the last 200mm and extends it to 800mm, a 4x extension, so that the effective focal length of that objective is 3200mm. Use that with a 25mm eyepiece and the magnification is 3200/25 = 128. By the way, if a telescope is smaller than you are, it is seldom much use to view using a magnification greater than 50 to 100. Most objects are best viewed at relatively low powers such as 30 or so.
285 X maximum "usable" magnification