Astro:...::CoCo(3pm)

📦 version 1.26, in alpine 3.24

💫 Astro:...::CoCo(3pm) 💫

okay so this is Astro:...::CoCo, straight out of the User Contributed Perl Documentation section, and it's basically the coordinate-conversion bestie of the Astro::Montenbruck world ✨

🌸 NAME 🌸

Astro::Montenbruck::CoCo — Coordinates conversions. that's it, that's the whole vibe. she converts coordinates. periodt 💅

🎀 VERSION 🎀

Version 0.01 — baby's first version, and she's already iconic 🫶

🦋 DESCRIPTION 🦋

Celestial sphera related calculations used by Astro::Montenbruck modules.

like, literally all the sky-sphere math that the rest of the Montenbruck family leans on? she's the one doing it. main character energy fr fr 🌌

⭐ EXPORT ⭐

these two get exported for you automatically, no extra asking required:

  • equ2ecl($alpha, $delta, $epsilon)
  • ecl2equ($lambda, $beta, $epsilon)

slay. go use them 💖

🔥 FUNCTIONS 🔥

🌈 equ2ecl($alpha, $delta, $epsilon)

Conversion of equatorial into ecliptic coordinates. one door in, the other door out 🚪✨

Arguments

  • $alpha — right ascension
  • $delta — declination
  • $epsilon — ecliptic obliquity

Returns

Ecliptic coordinates:

  • $lambda
  • $beta

All arguments and return values are in degrees. every single one. degrees only, no cap 📐

💜 ecl2equ($lambda, $beta, $epsilon)

Conversion of ecliptic into equatorial coordinates. the reverse trip, same energy 🦋

Arguments

  • $lambda — celestial longitude
  • $beta — celestial latitude
  • $epsilon — ecliptic obliquity

Returns

Equatorial coordinates:

  • $alpha — right ascension
  • $delta — declination

All arguments and return values are in degrees. again. degrees. always degrees 💅

👑 equ2hor($h, $delta, $phi)

Conversion of equatorial into horizontal coordinates. we're going from sky-coords to "where do i point my eyeballs" coords 🔭

Arguments

  • $h — the local hour angle, in degrees, measured westwards from the South. h = Local Sidereal Time - Right Ascension
  • $delta — declination, in arc-degrees
  • $phi — the observer's latitude, in arc-degrees, positive in the nothern hemisphere, negative in the southern hemisphere.
yeah bestie, "nothern" — that's how it's spelled in the source, we're not touching it, it's canon now 🙈

Returns

Horizontal coordinates:

  • azimuth, in degrees, measured westward from the South
  • altitude, in degrees, positive above the horizon

northern observers, southern observers, everybody gets a horizon 🌅

🧚 hor2equ($az, $alt, $phi)

Convert horizontal to equatorial coordinates. the comeback arc 💫

Arguments

  • $az — azimuth, in degrees, measured westward from the South
  • $alt — altitude, in degrees, positive above the horizon
  • $phi — the observer's latitude, in arc-degrees, positive in the nothern hemisphere, negative in the southern hemisphere.

Returns

Horizontal coordinates:

  • hour angle, in arc-degrees
  • declination, in arc-degrees
lowkey a little goofy — the docs label this return list "Horizontal coordinates" even tho you literally just converted to equatorial, and we're preserving that exactly as written 🫶 the values you get back are the hour angle and the declination, fr fr.

💀 SUPPORT 💀

You can find documentation for this module with the perldoc command. iconic behavior, honestly:

perldoc Astro::Montenbruck::CoCo

🌸 AUTHOR 🌸

Sergey Krushinsky, "<krushi at cpan.org>" — thank you for the coordinates, king 👑

Copyright (C) 2009-2022 by Sergey Krushinsky

This library is free software; you can redistribute it and/or modify it under the same terms as Perl itself.

and that's the whole page, bestie!! 🎀 this beauty shipped as part of perl v5.42.2, dated 2026-02-15, and it's giving "small module, huge responsibility." mwah 💋✨

📦 where this page comes from