Special Mic How to buy outdoor telescope for outdoor telescope
What parameters should I buy Outdoor Telescope?
For example, the word "10x40" is printed on the left mirror shoulder. 10 indicates that the target is observed by the Telescope, which is 10 times more than the directly observation of the naked eye. Objects with a distance of 1,000 meters away are equivalent to only 100 meters away.
40 means that the diameter of the objective mirror is 40 mm. The larger the diameter of the objective mirror, the brighter the imaging, but the portability will decrease.There is also the word "114m/1000m" on the shoulder of the left mirror, which means that at a distance of 1000 meters, the range that can be seen through this Telescope is a circle with a diameter of 114 meters.It is 6.5 degrees to change the angle.
Other Telescope uses XX FT AT 1000yds to represent the size of the field. FT represents feet and YDS represents code. They are all British units.
2. BAK4 and BK7 material
BAK4 and BK7 are numbers of two different material optical glass.The refractive index of these two glass is different. The refractive index of BAK4 is high. For the PORRO prism material of BAK4, the incident light can be reflected 100%without considering absorption.Therefore, BAK4 has high light efficiency, but its price is also expensive. military Telescope and some high -quality civilian mirrors use Bak4 prism.The easiest way to judge the prism material is to view the shape of the pupil behind the eyepiece.
For the ROOF prism, because of its special structure, there is no difference in using these two materials, and the prism material cannot be distinguished from the shape of the pupil.For commercial considerations, it is meaningless from technical.
3. The significance of lens coating
When the light is on the surface of the lens, some light will be reflected. A typical Telescope has more than 10 reflective surfaces. Even if each reflection surface only reflects a few percentage Lights, plus the inside of the lens absorbs light, and finally enters into the lens.The light of the eyes may lose more than 50%, not only the imaging is dim, but also reflects the inside of the Telescope multiple times. Part of the eye mirror enters the eyes, forms glare, interference observation, and reduces the contrast of the imaging.
When a thin film on the surface of the lens is plated on the surface of the lens, it can improve the light transmission of this wavelength and light. The more common blue film is the simplest diaphragm.Movies can enhance the light transmittance of the entire-see-light-wave-paragraph.
There are many red film Telescopes on the market. This mirror is generally only applicable to high -light light environments such as snow. Daily use will cause problems such as dull imaging and severe color.In addition, in order to reduce costs, some mirrors are coated only on some lenses (generally the outer surface of objectives and eyepiece). Good mirrors will be coated on all lens surfaces. A better mirror will be plated on the surface of some lenses on multi -layer membranes on the surface of the lens surface.The best mirror will be plated on the surface of all the lens.The easiest way to judge the coating of a mirror is to observe the reflection of the lens. The darkened the reflective, the more transparent the lens, the better the coating.
4. waterproof and all -metal structure
Many Telescope will focus on highlighting the characteristics of nitrogen waterproof, because this is a typical feature of high -quality Telescope.It means that neither water vapor and dust cannot enter the interior of the Telescope. With the protection of dry nitrogen, the internal lenses will not be fog and mold, ensuring the long life of the Telescope, and it is also suitable for extremely harsh environments.Therefore, the general military Telescope, such as 95, uses the design of nitrogen -filled waterproof.Some civilian mirrors also use this design, and the price is very cheap, and 100 are available.
In addition, it is important to emphasize that this design does not directly bring optical improvement, and the only improvement is durability.At present, the Russian Telescope and domestic regular military Telescope are all metal structures (usually aluminum, and old -fashioned military Telescopes are often used by brass). The benefits of this structure are very durable, and there are disadvantages that are slowly aging and easy to deform.Although it cannot directly bring optical progress, it can ensure that optical parts have been in accurate positions, which will bring long -term stability in optics.Because the cost of metal structure is high, this structure is only used by military Telescopes and high -end civil microscopes, and ordinary civilian Telescope often uses a mixed structure of metal and plastic.
5. Porro (Paul) and ROOF (roof) prism
The image seen through a typical Campler Telescope is upside down upper, lower, left and right. In order to meet the needs of ground observation, a set of prism must be added behind the objective mirror (the real image of the distant goal).Turning to a positive image.The prisms with two structures have two structures, Porro prisms and ROOF prism.
The advantage of the Porro prism is that the structure is simple, the light transmittance is high, and the imaging quality is good, but the volume of the Telescope is large.
In order to overcome this shortcoming, the reverse Porro prism can be used, but it also brings new problems. The caliber of the objective mirror is small and is not suitable for use in a low -illumination environment.
The biggest advantage of the ROOF prism is that the volume of the Telescope after it can be used to the smallest, and the weight of the Telescope also decreases. However, the structure of this prism is complicated, and the transmission rate is 5%lower than the Porro prism.To be a high -quality ROOF prism Telescope, you need to pay a lot of money.
6. The diameter of the pupil and the distance of the pupil
The diameter of the pupil is the light spots formed by the image after the Telescope.
This is also an important indicator of the Telescope. It represents the success of the Telescope-like-bright-degree. If the distance from the pupil is too short, the eyes must be close to the eyepiece to see the entire viewing field.The pupil distance is too long and the goggles are too short, so it is easy to appear dark shadow when observing.The Telescope that grows the distance is suitable for people who wear eyes.Some grow pupil Telescope mirror hoods are designed as telescopic type, which is suitable for people with normal vision and people with eyes.
Generally speaking, the Telescope with pupils between 2.5 mm and 4 mm is more suitable for daily use. The Telescope between 4 mm and 7 mm, the day and low -illumination environment can still be observed, while the Telescope below 2.5 mm, even if the Telescope is below 2.5 mm, even if the Telescope below 2.5 mm, even if youDuring the day, the imaging brightness is also very low, and it is difficult to align with the pupils of the human eyes, and the comfort of observation is poor.The simple calculation formula of the pupil is the diameter/multiple of the objective mirror = the diameter of the pupil.For example, the 7x50 Telescope, the diameter of the pupils = 50/7 = 7.14 mm.The pupil distance refers to the longest distance of the eyes to see the eyes of the eyes.
Generally speaking, ordinary handheld Telescope multiple should not exceed 10 times, because there will be slight jitter when holding the Telescope. When observing through the Telescope, this jitter will be large.There is no way to see the eyes that are shaking violently.This is also the reason why the magnification of the tancing mirror is generally only 7/8 times.The same diameter Telescope, the larger the view of the multiples.
Even the Telescope observed on the tripod, the multiple is limited, because the atmosphere is affected by the ground building and other factors, the density is not uniform.When passing through these uneven density atmosphere, slight refraction will occur, causing the image to blur.And the higher the Telescope multiple, the more obvious this vague.Generally speaking, in low altitude cities, the multiples of the Telescope should not exceed 40 times.
In addition, the magnification is large, and the actual field is small.In this way, it is not conducive to discovering and finding goals, and it is particularly unfavorable to observation of changing goals.Even if you find the target, the tripod shakes a little and it is easy to lose the target.For those without automatic tracking devices, they must be manually adjusted to keep the target in the field of vision.
In addition, the increase of multiples must also be required to improve the caliber of the material mirror to ensure that the imaging has sufficient brightness, and the human eye without brightness is unclear.In this way, the size and price of the Telescope will increase sharply.However, it should not be pursued one -sided pursuit. As for many high -magnitude binoculars on the market, the multiple is generally exaggerated, and a small part of the multiple is true. The reason for this situation is very simple.It is not popular Telescope knowledge. Since the market needs a high -power Telescope, it is better to meet the correct consumption concept of consumption.So choosing a Telescope is best to be a big brand Telescope.Generally speaking, the Telescope with a larger diameter and a higher Telescope is higher, and the coated mirror is more distinguished.
It is important to emphasize that the multiple of the Telescope is only one of the many associated factors that affect the resolution. It is not advisable to blindly pursue a large multiple.
outdoor sports Telescope buying points:
1. Waterproofing nitrogen and waterproof, outsourcing rubber, has a suitable multiple and caliber, portability and ease of use. Of course, the excellent optical quality is at least.The outdoor sports referred to here generally refer to the Hiking backbone camps, and the requirements for the Telescope are relatively complicated.
2. In order to prevent the penetration of rainwater or the foggy of lenses in the cold weather or the entry of dust caused by severe use for a long time, nitrogen -filled waterproof can fundamentally solve this problem.The sealing of the military Telescope with nitrogen is also very good. As long as it is not soaked in the water, the general rain and snow wind can still be dealt with.
3. Long -term use in the wild, unintentional bumps are inevitable. The design structure or unsatisfactory Telescope mirror can easily lead to optical damage such as shaft biased shadow.Rubber is a very good protection measure. In addition to shock absorption, it can also improve the feel and grip.Outdoor, the purpose of the Telescope is mostly observed, appreciating the landscape, bird watching beasts, and considering the requirements of hand shock and optics, the multiple of which is used at 6-8 times is very suitable.
4. As for the caliber, 20-40mm is ideal according to the focus and requirements of use.outdoor sports itself requires individuals to carry a large amount of equipment and supplies. When each gram of weight affects physical strength, it is unrealistic about pursuing optical performance and ignoring the volume and weight.The contradiction with optical properties is irreconcilable. Mirrors with large -caliber high brightness will inevitably lead to a sharp increase in the overall weight. Therefore, it can only make its own satisfactory compromise between weight and optical requirements according to personal requirements and hobbies.The Telescope of the roof spinal prism has a relatively small volume and weight, which is easy to carry. The disadvantage is that the price of complex manufacturing is relatively high.
5. Some basic optical indicators about the Telescope have their own definition and resolution for outdoor sports: This is the primary indicator. The poor resolution mirror can help you see the crocodile as a trunk.Pupil: It can be calculated simply with a multiples. The larger the number, the more suitable to capture your prey under dark light.
6. color restoration: The colors exist on many Telescope. The general observation may be not so strict, but if it is used for wild birds, you cannot correctly describe the color of bird feathers.Coating: The fake Russian Telescope using the street bright and flashing red film is really rape of the eyes. It causes light to lose light, the color restoration of the color, and it is easy to cause uncomfortable glare. The best coating can make you almost invisible the existence of the lens.Essence
In short, for different people, due to the different requirements, the choice of Outdoor Telescope will also be very different. There is no law of uniform applications. According to your requirements and preferences, choosing a suitable Outdoor Telescope will be right.Your wild life brings great fun.
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