In terms of observation effect, the effect of the binoculars of the same specification is much better than that of the monocular, the image is full of three-dimensionality, the resolution is higher, the imaging is brighter, and the observation is more comfortable, but the volume and weight of the monocular is more than half smaller than that of the binocular of the same specification. , it is easier to achieve high magnification zoom with a single tube, such as bird watching scopes. Therefore, for hand-held telescopes, binoculars are recommended for better results, and monoculars are recommended for more compact size. If you can use a tripod and want to get a high-magnification zoom effect, a monocular bird watching spotting scope is recommended.

How many ways are there to represent the field of view?

Common methods include degrees, xxx meters/1000 meters, xxx yards/1000 inches and other methods. Taking 125 meters/1000 meters as an example, it means that when a telescope is used to observe a target 1000 meters away, the range that can be seen is a circular area with a diameter of 125 meters. In addition, take an 8x telescope with an actual field of view of 7.5 degrees as an example. Although the actual observation range is only 7.5 degrees, because the telescope has an 8x magnification effect, the apparent field of view is 7.5x8=60 degrees, which does not feel cramped. A telescope with an apparent field of view exceeding 60 degrees can be considered a wide-field telescope.

The algorithm and meaning of exit pupil diameter?

Exit pupil diameter = telescope objective lens diameter ÷ magnification, such as 8X30 telescope, exit pupil diameter = 30÷8 = 3.75 mm, if the exit pupil diameter is less than 3 mm, such as 8X21, 10X25 specifications, generally only suitable for the environment with sufficient light Observe below. The diameter of the exit pupil is more than 5 mm. For example, the 8X42 and 7X50 specifications can be observed in low-light environments (dusk, dawn, moonlight, etc.), but the telescope cannot be observed in a completely dark environment.

What is the difference between a Porro prism and a roof prism?

If there is no prism transfer, the image we see is an inverted image. The prisms often used in hand-held telescopes are divided into Porro prisms and roof prisms. Using Porro prisms, the imaging effect is good and the price is low, but the volume and weight are too large. The roof prism is used, which is small in size and weight, but has the shortcomings of double aberration, phase difference, and no total reflection. It is necessary to use high-precision prisms, phase films and high-reflection films to overcome these defects, resulting in relatively expensive telescopes.