Spotting scope
A spotting scope (abbreviated from Perspective from Latin perspectivus , looking through, through; English spotting scope ), also called an observation telescope , is a mostly monocular telescope or optical telescope designed for daytime observation of the earth . Binocular devices are sometimes called double spotting scopes. In contrast to the astronomical telescope of the Kepler type , spotting scopes produce upright, laterally correct images.
Areas of application
Typical areas of application are nature observation ( hunting , bird watching ), spotting , sports (e.g. target observation ) as well as civil and military surveillance .
design type
In order to be easily transportable and usable with a tripod in wind and weather , a spotting scope is ideally compact, relatively light (depending on the lens size between 500 and 2000 grams) and robust (shockproof, waterproof). Most models are available with a 45 ° angled viewer for easy observation, but spotting scopes with straight viewer are also manufactured. In addition to the widespread models with a rigid body, so-called pull-out perspectives are also offered. These can be pushed together telescopically for more compact packing dimensions. Due to the design, however, this type of spotting scope cannot be waterproof. As with binoculars, the overall trend is towards ever lighter and more compact designs.
Often encountered objective diameters ( apertures ) are 50, 60, 62, 65, 77, 80, 82, 85 and 100 millimeters with magnifications of 20-80x with interchangeable or zoom eyepieces. At high magnifications, apochromats and expensive special glasses are necessary to avoid color fringes. Such designs can be seen z. B. abbreviations such as Apo, ED, FL, HD. But even these cannot prevent blurring due to atmospheric cloudiness and summer heat shimmer, which often become more noticeable with increasing magnification.
As with astronomical telescopes, different eyepieces can be mounted in order to adapt the magnification and the field of view depending on the application . A distinction can be made between fixed focal length and zoom eyepieces. The former have a fixed magnification (e.g. 20, 30 or 40 times magnification) and are often manufactured as special wide-angle eyepieces. Zoom or vario eyepieces usually have a rotatable ring that can be used to vary the magnification (zoom).
The vast majority of the spotting scopes are telescopes in terms of their structure, and less often reflector telescopes , e.g. B. after Maksutov .
Others
To avoid blurring, a spotting scope should be attached to a sufficiently stable tripod with a suitable 2-way pan head .
As a more recent development, video or photo cameras and smartphones can be connected directly to the spotting scope body or the eyepiece with the help of special adapters. The spotting scope becomes a photographic telephoto lens. This photo technique is English. digiscoping , German digiscoping called.
On the other hand, interchangeable lenses of SLR cameras can be converted into a spotting scope with an adapter. This contains a fixed eyepiece. The magnification results from the objective focal length divided by the eyepiece focal length. With a Canon EF 100-400mm lens in conjunction with a Kenko Lens2scope with 10mm, this results in 10-40x magnification. Teleconverters can be used and increase the magnification accordingly (1.4 ×, 2 ×, 3 ×). The image quality corresponds to a mid-range spotting scope.
The properties mentioned make a spotting scope interesting as a "travel telescope" for amateur astronomers, because the imaging performance is on a par with a "real" telescope. With some spotting scopes, particularly high-quality 1¼-inch astro-eyepieces can be connected using an eyepiece adapter. With this connection with a so-called astro adapter, however, it should be noted that only very few astro eyepieces fit. Usually the problem is then to be able to focus on infinity. However, there are also spotting scopes with a standard 1¼-inch eyepiece connection. Almost all astro eyepieces can be attached there.
Manufacturer
Manufacturers of spotting scopes are for example Bresser , Carl Zeiss Sports Optics , Celestron , Eschenbach Optik , Kōwa , Leica , Meade , Meopta , Minox , Nikon , Optolyth , Pentax , Swarovski and Yukon.
literature
- Klaus-Dieter Linsmeier: Long-range optics in nature observation. Function, application and manufacture of binoculars, telescopes and riflescopes. ISBN 3-478-93215-7 .
- Magazine birds - magazine for bird watching . ISSN 1862-8397 , reports regularly on long-range optics.