# Meaning of superscript letters in sidereal time calculation

I'm following along with Dr Kelso's columns on CelesTrack and I've come across this equation.

$$θ_g(0^h)=24110^s.54841+8640184^s.812866T_u+0^s.093104T_u^2- 6.2\times10^{-6} T_u^3$$

As you can see, there are superscript $$^s$$s right before the decimal point on some of these values and a superscript $$^h$$s next to the 0 argument in the function definition.

What do these signify? Is it the unit of the terms? If so, it's weird notation I've never seen before.

• The " Explanatory Supplement to the Astronomical Almanac" is available here archive.org/details/… where you can read the page 50 reference. The whole "Time" chapter seems to use that notation for days, hours, minutes, seconds. See page 41. Jan 10 at 14:42
• Perfect, thank you! Do you want to write that up as an answer or should I? Jan 10 at 16:26
• Go for it, not my wheelhouse. Jan 10 at 16:35
• FYI StackExchange supports LaTeX markup via MathJax, which you could use instead of the inline image. Jan 10 at 19:28
• @ErinAnne - Ahh, I thought that was only enabled for Math.SE Jan 10 at 21:17

$$θ_g(0^h)=24110^s.54841+8640184^s.812866T_u+0^s.093104T_u^2- 6.2\times10^{-6} T_u^3$$
• @ScottishTapWater This is fairly common in astronomy. For example 123.456 degrees will oftentimes be marked as $123^\circ.456$ as opposed to $123.456^\circ$. Jan 11 at 14:21