In fact, as we’ll see in a moment, your telescope is actually capable of many different magnifications, by combining it with different eyepieces. For instance, a 1 arc minute object magnified to 1° apparent size will have actual magnification of 60, exactly as the formula indicates. April 28, 2019 by Veerendra. Lens Formula & Magnification – Lens Power. Formula to calculate magnification. Angular magnification — For optical instruments with an eyepiece, the linear dimension of the image seen in the eyepiece (virtual image in infinite distance) cannot be given, thus size means the angle subtended by the object at the focal point (angular size). Distance 25 cm Miso-acc = 1 + F/4 Three assumption inherent in above formula Magnifier to eye distance is negligible The reference viewing distance is 25 cm The image produced by the magnifier is also at 25 cm Thus accommodative state / … The objective lens gathers light from the specimen, which is focused to produce the real image that is seen on the ocular lens. Assumptions made: Angular Magnification Telescope ... rating magnification For Ref. The eyepiece or ocular lens, is placed near the focal point of the objective to magnify this image. Then the image resolution at this magnification = 120/30 = 4 arcseconds. In order to have large magnifications compound microscope is used. An astronomical telescope has an angular magnification of magnitude 5 for distant objects. The eyepiece has a field of view of 52°, so the field of view for the telescope at this magnification will be 52 ÷ 30 = 1.7°. The lens nearest the object, called the objective, forms a real, inverted, magnified image of the object. If you want to calculate the magnification of your telescope, you’re in luck: It’s a surprisingly simple formula. With the tangent increasing faster than the angle, large angular objects in the eyepiece will have lower actual magnification than indicated by this formula. Example: The separation between the objective and an eye piece is 36 cm and the final image is formed at infinity. Then the magnification is f O /f e = 762/25 = 30.48, which we would just call 30. Numerical Methods In Lens (A) Lens Formula Definition: The equation relating the object distance (u), the image distance (v) and the focal length (f) of the lens is called the lens formula. The angular magnification is m =( θ i / θ 0) =(D/f) Compound Microscope.