I understand that the hour angle and declination can be abbreviated as (HA Decl), and rectascension and declination as (RA Decl). The hour angle of a star is of course zero hours at the meridian.

The Sun however does have solar time 12 hours at the meridian, and the "solar" hour angle would better be 12 hours. Therefore I look for an abbreviation for use in computer programming for the pair (solar time, declination) or (sun hour angle, declination), and I can't make up them. I didn't anywhere find them naturally, say in Wikipedia or through Google.

I considered (SOL Decl), (SHA Decl), (ST Decl) or the german (SZ Decl). I don't want to use (HA Decl) for the sun, because HA is zero at the meridian, but as already said for the sun its hour angle should be 12 at the meridian and therefore for clarity and for programming purposes, another designation is needed.

My angles are local, there is no need for a compulsary prefix L- (local) or G- (Greenwich).

I know that in english usage is "apparent" sun hour angle, but in german it would be "true" sun hour angle, therefore the word element "apparent" should be absent.

The question is not about the formulas proper for hour angle or solar time.

Thank you.

  • $\begingroup$ Instead of "apparent" is "evident" better? -- Does an Article on Solar Calculations provide any hints: holbert.faculty.asu.edu/eee463/SolarCalcs.pdf -- Is there Open Source software that provides names (and formulas) for the Variables you wish to name? $\endgroup$
    – Rob
    Dec 19, 2017 at 7:32
  • $\begingroup$ Azimuth or Elevation Angle? $\endgroup$
    – Rob
    Dec 19, 2017 at 7:44
  • $\begingroup$ "I can't make up them" Why not? or why not "solarHourAngle" or something. $\endgroup$
    – James K
    Dec 19, 2017 at 8:35
  • $\begingroup$ @ Rob, the article provided AST $\endgroup$
    – Peter
    Dec 20, 2017 at 8:27

1 Answer 1


Use SHA, solarHourAngle or some variant thereof, as James K said, if your programming language allows it. Longer variable names can be more cumbersome to type and have more possibility of mis-typing the name, but can save a lot of time by providing clarity of purpose when reviewing code at a later date.

  • $\begingroup$ unfortunately SHA is Sidereal Hour Angle, by Wikipedia [link]en.wikipedia.org/wiki/Hour_angle#Solar_hour_angle. Wiki mentions Solar Hour Angle but does not give a shortcut abbreviation. Everything starting with S can be read as Star or Sun (german names), Sidereal or Solar (english equivalent names). I look for something short for a single-line printout. Sun x-coord y-coord z-coord w-coord LST 9.3566 Decl -23.427 which is right now. $\endgroup$
    – Peter
    Dec 20, 2017 at 8:41
  • $\begingroup$ would SH for solar hour sound reasonable to english-listening ears: SH 2.4149 Decl -23.433 ? Something containing hour instead of time or angle. They key to the toString(key) printing function would then be 'SHDecl'. $\endgroup$
    – Peter
    Dec 22, 2017 at 1:57

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