Ads
related to: diy focusing hood right angle viewfinder for polar scope combo base station
Search results
Results From The WOW.Com Content Network
A 50mm right-angle finderscope mounted on a 150mm telescope. Tour guide points out the double Finderscope on the 24.5 inch Cassegrain Telescope at the Goldendale Observatory State Park . A finderscope is an accessory sighting device used in astronomy and stargazing , typically a small auxiliary refracting telescope / monocular mounted ...
English: ARPES spectrometer measures angular dispersion in a slice α along its slit, so in order to map the band structure over a two-dimensional momentum space one needs to turn the sample, changing its roll/polar angle ϑ, pitch/tilt τ, or yaw/azimuth φ. Here, the change in polar angle is shown: ϑ=-25°, τ=0°, -8°≤α≤8°.
Once the radius is fixed, the three coordinates (r, θ, φ), known as a 3-tuple, provide a coordinate system on a sphere, typically called the spherical polar coordinates. The plane passing through the origin and perpendicular to the polar axis (where the polar angle is a right angle) is called the reference plane (sometimes fundamental plane).
Lens hoods are more prominent in long focus lenses because they have a smaller viewing angle than that of wide-angle lenses. For wide angle lenses, the length of the hood (away from the end of the lens) cannot be as long as those for telephoto lenses, as a longer hood would enter the wider field of view of the lens. [5]
A large German equatorial mount on the Forststernwarte Jena 50cm Cassegrain reflector telescope.. An equatorial mount is a mount for instruments that compensates for Earth's rotation by having one rotational axis, called polar axis, parallel to the Earth's axis of rotation.
A diagram of a typical nautical sextant, a tool used in celestial navigation to measure the angle between two objects viewed by means of its optical sight. Celestial navigation, also known as astronavigation, is the practice of position fixing using stars and other celestial bodies that enables a navigator to accurately determine their actual current physical position in space or on the ...
Star trail image of the north polar region. A digital camera with a standard lens is mounted on the telescope and pointed at the celestial pole. Exposure is set at "B" (Bulb) and an image is taken while the camera is slowly turned around the polar axis. [7] This yields a kind of star-trail image.
A focusing screen is a flat translucent material, either a ground glass or Fresnel lens, found in a system camera that allows the user of the camera to preview the framed image in a viewfinder. Often, focusing screens are available in variants with different etched markings for various purposes. [ 1 ]