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  2. Polar alignment - Wikipedia

    en.wikipedia.org/wiki/Polar_alignment

    In the Northern Hemisphere, rough alignment can be done by visually aligning the axis of the telescope mount with Polaris.In the Southern hemisphere or places where Polaris is not visible, a rough alignment can be performed by ensuring the mount is level, adjusting the latitude adjustment pointer to match the observer's latitude, and aligning the axis of the mount with true south or north by ...

  3. Setting circles - Wikipedia

    en.wikipedia.org/wiki/Setting_circles

    Also, even the finest graduations on setting circles are usually more than a degree apart, which makes them difficult to read accurately, especially in the dark. Nothing can be done if the optical tube is not perpendicular to the declination axis or if the R.A. and Dec axes are not perpendicular, because these problems are next to impossible to ...

  4. Equatorial mount - Wikipedia

    en.wikipedia.org/wiki/Equatorial_mount

    German equatorial mount. In the German equatorial mount, [4] (sometimes called a "GEM" for short) the primary structure is a T-shape, where the lower bar is the right ascension axis (lower diagonal axis in image), and the upper bar is the declination axis (upper diagonal axis in image).

  5. Optical margin alignment - Wikipedia

    en.wikipedia.org/wiki/Optical_margin_alignment

    Optical margin alignment is designed to be used for body text, and not for display type, text in tables, or headlines. It is often used for block quotes, which benefit from “hung punctuation.” In such cases, the leading quotation mark is outdented 100% into the margin or paragraph indent, so that subsequent lines of text align with the ...

  6. Nonimaging optics - Wikipedia

    en.wikipedia.org/wiki/Nonimaging_optics

    Nonimaging optics (also called anidolic optics) [1] [2] [3] is a branch of optics that is concerned with the optimal transfer of light radiation between a source and a target. . Unlike traditional imaging optics, the techniques involved do not attempt to form an image of the source; instead an optimized optical system for optimal radiative transfer from a source to a target is desi

  7. Spherical coordinate system - Wikipedia

    en.wikipedia.org/wiki/Spherical_coordinate_system

    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).

  8. Circular polarization - Wikipedia

    en.wikipedia.org/wiki/Circular_polarization

    The result of this alignment are select vectors, corresponding to the helix, which exactly match the maxima of the vertical and horizontal components. To appreciate how this quadrature phase shift corresponds to an electric field that rotates while maintaining a constant magnitude, imagine a dot traveling clockwise in a circle.

  9. Stereographic projection - Wikipedia

    en.wikipedia.org/wiki/Stereographic_projection

    P is a point on the sphere, but not a 'north pole' N and not its antipode, the 'south pole' S, P ′ is the image of P in a stereographic projection with the projection point N and; P″ is the image of P in a stereographic projection with the projection point S, then P ′ and P″ are inversive images of each other in the unit circle.