sighting tube การใช้

• The double ring holds within itself a sighting tube with crosshairs.
• The archaeological record is full of such devices; simple inclinometers and diopters and sighting tubes extend through to ancient Sumerian times.
• Many users prefer a simple sighting tube, which has a wider, brighter field of view and is easier to use at night.
• By comparing the position of the bar suspended from the sighting tube to the Corrector's vertical scale, they would see it indicate + 1000.
• RightAn example of such a scale hypsometer is illustrated here, and can be seen to consist of a sighting tube, a fixed horizontal scale, and an adjustable vertical scale with attached plumb line.
• When observing, astronomers would aim at the star with the sighting tube, whereupon the star's position could be deciphered by observing the dials of the equatorial ring and the right ascension double ring.
• Shen Kuo calibrated the standard diameter of the sighting tube's width, hence allowing the observation of the pole star indefinitely ( which had shifted since the time of Zu Geng in the 5th century ).
• Richer wrote about another of Gerbert's last armillary spheres, which had sighting tubes fixed on the axis of the hollow sphere that could observe the constellations, the forms of which he hung on iron and copper wires.
• An "'Abney level and clinometer "', is an instrument used in surveying which consists of a fixed sighting tube, a movable spirit level that is connected to a pointing arm, and a protractor scale.
• To measure lines on a particular slope, the desired angle or grade is first set on the level and then the surveyor sights through the sighting tube and brings the cross-hair in line with the bubble in the level while viewing the target.
• Furthermore, Gerbert instructed Constantine that the north pole could be measured with the upper and lower sighting tubes, the Arctic Circle through another tube, the Tropic of Cancer through another tube, the equator through another tube, and the Tropic of Capricorn through another tube.
• Gerbert instructed Constantine that, if doubtful of the position of the pole star, he should fix the sighting tube of the armillary sphere into position to view the star he suspected was it, and if the star did not move out of sight, it was thus the pole star.
• The Abney level is a handheld surveying instrument developed in the 1870s that includes a sighting tube and inclinometer, arranged so that the surveyor may align the sighting tube ( and its crosshair ) with the reflection of the bubble in the spirit level of the inclinometer when the line of sight is at the angle set on the inclinometer.
• The Abney level is a handheld surveying instrument developed in the 1870s that includes a sighting tube and inclinometer, arranged so that the surveyor may align the sighting tube ( and its crosshair ) with the reflection of the bubble in the spirit level of the inclinometer when the line of sight is at the angle set on the inclinometer.