Telescope buying a academic term commentary to help you see more clearly and farther

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Telescope choice

Purchase by the environment

If you think of travel at sea or seaside, don't forget to buy a waterproof Telescope.

If you want to go out for tourism, you can buy a small Telescope with a small volume.

If you intend to go to the dangerous areas that can be seen from a distance but not to detect ", you should buy a high -multiples Telescope.

If you want to hunt or travel for a long time, it is best to buy a variable multiples Telescope, which shows how it uses it.Because the changeable Telescope can be gradually adjusted from the low multiplier to the high multiplier, the low multiplier and large field of view should be used for roughly when used, and then carefully observed with a high multiplier and small field of vision.

What are the terminals?

caliber

This is the most important factor when choosing an astronomical Telescope. The primary function of the Telescope is to collect light. No matter how much the magnifying magnification, the better the imaging.The diameter of the Telescope is to expect the glass diameter of the remote mirror or the main lens size, which is represented by millimeters or inch.The greater the diameter, the stronger the ability to collect light, the better the imaging.The larger the diameter, the clearer the details of the picture. For example, when observing a spherical nebula of a M13, a 4 -inch caliber Telescope needs to use 150 power supply, but the 8 -inch caliber Telescope also uses the same ones with the same ones.Power, but Nebula images are 16 times clearer than 4 inches.Even the stars under the weak light can be seen clearly.Considering that the user needs a long -caliber Telescope as much as possible, a large -caliber Telescope.The photos taken by a large -diameter Telescope have higher contrast, better resolution, and clearer.The Cyruster Telescope has "5 -inch caliber", "8 -inch caliber", "14 -inch caliber".

Discerning ability

This involves "Douas restrictions".The distinction between two tight twins, theoretically the ability to distinguish the Telescope is determined by 4.56 to remove the caliber of the Telescope.For example: a resolution ability with a diameter of 8 -inch is 0.6 (4.56/8 = 0.6) that directly affects the distinguishing ability of the Telescope is the caliber of the Telescope. Therefore, the larger the Telescope, the better the resolution ability.However, the ability to distinguish also depends on the influence of the atmosphere and the acuity of people observing objects.

Pupil diameter

The diameter of the pupil is a circular beam that appears in the case of a Telescope without eyepiece, which is represented by mm (millimeters).Calculate the diameter of the pupil, for example: a Telescope with a diameter of 8 inches (203mm), uses a zoom distance of 20mm eyepiece to place 102 times large, and the pupil diameter is 2mm (203/102 = 2mm).Or you can also use the focus of the Telescope to remove the diameter of the pupil with the focal length of the eye mirror.

Extreme Star et al.

Astronomers use a star and other systems to explain the level of bright stars. A star body is considered to have a certain star. The higher the level, the darker the star.The value of the stars) is about 2.5 times the stars. The darkest star body that you can see with your naked eye is about six -class stars (in the night sky). On the contrary, the brightest star is 0 and the stars (orEven negative values).See the darkest star body with a Telescope (the best time in various environments), that is, the extreme star, etc., the extreme star, etc. directly depends on the caliber of the Telescope.EssenceRoughly calculating the formula of Extreme Star is: 7.5 5 LOG (represented by CM).For example: The extreme star with a diameter of 8 inches is 14.0 (7.5 5 log 20.32 = 7.5 (5x1.3) = 14.0).The situation of the atmosphere and the visual acuity of the observer will have an impact on extreme stars.Shooting extreme stars is about two or more than visual limit stars.

Vision

The range you can see when you observe the sky through a Telescope is the field of view, which is represented by an arc angle.The larger the view of the field of view, the greater the observation range. The calculation formula of the perspective angle is that the perspective angle of the eyepiece used is except the finger of the magnification of the Telescope.For example: If the eyepiece you use is 50 degrees, and the Telescope used with the mirror and the magnification of the eyepiece is 100X, then the visual field of the Telescope is 0.5 degrees (50/100 = 0.5).Born manufacturers usually specify the corners of their eyepiece. In general, the larger the viewing corner, the larger the view of the field of vision, because the more you see when you observe the starry sky. In addition, the more, Using a low -magnification astronomical Telescope is wider than seeing the high magnification.