Polar distance (astronomy)

This article has multiple issues. Please help improve it or discuss these issues on the talk page. (Learn how and when to remove these messages)

This article needs additional citations for verification. Please help improve this article by adding citations to reliable sources. Unsourced material may be challenged and removed.
Find sources: "Polar distance" astronomy – news · newspapers · books · scholar · JSTOR (June 2025) (Learn how and when to remove this message)

An editor has determined that sufficient sources exist to establish the subject's notability. Please help improve this article by adding citations to reliable sources. Unsourced material may be challenged and removed.
Find sources: "Polar distance" astronomy – news · newspapers · books · scholar · JSTOR (May 2025) (Learn how and when to remove this message)

You can help expand this article with text translated from the corresponding article in Polish. (May 2025) Click [show] for important translation instructions.

Machine translation, like DeepL or Google Translate, is a useful starting point for translations, but translators must revise errors as necessary and confirm that the translation is accurate, rather than simply copy-pasting machine-translated text into the English Wikipedia.
Consider adding a topic to this template: there are already 606 articles in the main category, and specifying|topic= will aid in categorization.
Do not translate text that appears unreliable or low-quality. If possible, verify the text with references provided in the foreign-language article.
You must provide copyright attribution in the edit summary accompanying your translation by providing an interlanguage link to the source of your translation. A model attribution edit summary is Content in this edit is translated from the existing Polish Wikipedia article at [[:pl:Odległość biegunowa]]; see its history for attribution.
You may also add the template {{Translated|pl|Odległość biegunowa}} to the talk page.
For more guidance, see Wikipedia:Translation.

You can help expand this article with text translated from the corresponding article in Portuguese. (May 2025) Click [show] for important translation instructions.

Machine translation, like DeepL or Google Translate, is a useful starting point for translations, but translators must revise errors as necessary and confirm that the translation is accurate, rather than simply copy-pasting machine-translated text into the English Wikipedia.
Consider adding a topic to this template: there are already 659 articles in the main category, and specifying|topic= will aid in categorization.
Do not translate text that appears unreliable or low-quality. If possible, verify the text with references provided in the foreign-language article.
You must provide copyright attribution in the edit summary accompanying your translation by providing an interlanguage link to the source of your translation. A model attribution edit summary is Content in this edit is translated from the existing Portuguese Wikipedia article at [[:pt:Distância polar (astronomia)]]; see its history for attribution.
You may also add the template {{Translated|pt|Distância polar (astronomia)}} to the talk page.
For more guidance, see Wikipedia:Translation.

(Learn how and when to remove this message)

In the celestial equatorial coordinate system Σ(α, δ) in astronomy, polar distance (PD) is an angular distance of a celestial object on its meridian measured from the celestial pole, similar to the way declination (dec, δ) is measured from the celestial equator.^[1]

Definition

[edit]

Polar distance in celestial navigation is the angle between the pole and the position of body on its declination.^[2]

Referring to diagram:

P- Pole, WQE- Equator, Z - Zenith of observer,

Y- Lower meridian passage of body

X- Upper meridian passage of body

Here body will be on declination circle (XY). The distance between PY or PX will be the Polar distance of the body.

NP=ZQ=Latitude of observer

NY and NX will be the True altitude of body at that instant.

Polar distance (PD) = 90° ± δ

Polar distances are expressed in degrees and cannot exceed 180° in magnitude. An object on the celestial equator has a PD of 90°.

Polar distance is affected by the precession of the equinoxes.

If the polar distance of the Sun is equal to the observer's latitude, the shadow path of a gnomon's tip on a sundial will be a parabola; at higher latitudes it will be an ellipse and lower, a hyperbola.