Witam
Proszę o podpowiedz - gdzie będzie godzina 12 czasu letniego W zegarze wertykalnym o 10 st. deklinacji sciany w kierunku południowo-wschodnim . Miejscowy południk -17 st. E Szerokość geograficzna 52 st N.
Effect of declining on a sundial's hour-lines. A vertical dial, at a latitude of 51° N, designed to face due South (far left) shows all the hours from 6am to 6pm, and has converging hour-lines symmetrical about the noon hour-line. By contrast, a West-facing dial (far right) is polar, with parallel hour lines, and shows only hours after noon. At the intermediate orientations of South-Southwest, Southwest, and West-Southwest, the hour lines are asymmetrical about noon, with the morning hour-lines ever more widely spaced.
A declining dial is any non-horizontal, planar dial that does not face in a cardinal direction, such as (true) North, South, East or West.[1] As usual, the gnomon's style is aligned with the Earth's rotational axis, but the hour-lines are not symmetrical about the noon hour-line. For a vertical dial, the angle θ between the noon hour-line and another hour-line is given by the formula[2]
where λ is the sundial's geographical latitude, t is the time before or after noon, and η is the angle of declination from true South. When such a dial faces South (η=0°), this formula reduces to the formula given above, tan θ = cos λ tan(15° × t).
When a sundial is not aligned with a cardinal direction, the substyle of its gnomon is not aligned with the noon hour-line. The angle β between the substyle and the noon hour-line is given by the formula[2]
If a vertical sundial faces true South or North (η=0° or 180°, respectively), the correction β=0° and the substyle is aligned with the noon hour-line.
The height of the gnomon, γ (that is the angle the style makes to the plate) is[3]
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