What is a long eye relief eyepiece?
Above: Eye relief is the distance from the eyepiece to the observer’s eye Some eyepieces are specially designed to have long eye relief (LER), even at very short focal lengths. This makes high-magnification viewing much more comfortable. These eyepieces use more lens elements (usually 6-7) than a standard eyepiece.
What is Ramsden eyepiece?
noun Optics. an eyepiece consisting of two plano-convex crown-glass lenses of equal focal length, placed with the convex sides facing each other and with a separation between the lenses of about two-thirds of the focal length of each.
Why Ramsden eyepiece is used?
This eyepiece is effective in reducing chromatic aberration , doing a better job with longitudional achromatism than with lateral. Its approach to minimizing chromatic aberration is based on spacing the lens pair so that dependence upon the index of refraction is minimized.
What are Plossl eyepieces?
Steve says: “A Plössl eyepiece comprises four glass elements arranged as two back-to-back achromatic doublets; or, in other words, two pairs of two glass lenses. Advertisement. These eyepieces produce a ‘standard apparent feld of view’ of between 50° and 56° with most set at around 52°.
What is a Kellner eyepiece?
Kellner eyepieces feature a design with 3 lenses cemented together. This reduces chromatic (color) issues but comes at the expense of a narrow field of view. The field of view of a Kellner can go from 35 to 50 degrees.
Are Plossl eyepieces better than Kellner?
Both Plossl and Kellner have trouble with eye relief when it comes to high-powered eyepieces (below 10mm), but Plossls are slightly better. Plossls can also offer better performance when it comes to reducing optical error and delivering brighter colors.
Are Kellner EP’s any good?
Kellner is a type of lens arrangement, not a brand, so asking “are kellner ep’s any good” is a bit like asking “are refractor telescopes any good”. There’s no reason why a Kellner eyepiece shouldn’t (in theory) deliver views as good as a Plossl. Same goes for other similar designs such as Modified Achromat (which you link to).
What are the best eyepieces to start out with?
The eyepieces that come bundled with scopes are a modified kellner design and, as you will read in reports on here, those are just about OK to get started with. Plossls and orthoscopics are much better choices. More sharing options… Location: County Kildare,Ireland. Kellners will do as starter EP’s (if they came with your scope).