lortordermur/sfcalcsheet

The science fiction calculation spreadsheet

sfcalcsheet's Issues

No height adaption of word-wrapped cells in Excel

In Excel Online (and desktop Excel likely too), long footnotes currently look like this:

It appears that Excel does wrap the text properly but does not adjust the row height accordingly. If there is a fix for this, it has to be be implementable using cell styles rather than direct formatting.

Equatorial to Galactic and Trig calc PLS

I'm working on 3D starmaps in Astrosynth and Pioneer, I usually have to go through around 5 to 10 minutes hopping between my calculator and various online calculators and converters so I can convert Equatorial in to Galactic, and then calculate the trigonomic values so I can get cartesian co-ordinates. Would be handy if this calculator also had an Equatorial to Galactic converter, along with a right angle trig calculator for getting cartesian co-ordinates.

Proper illuminance formula in planetary habitability calculator

There is no proper illuminance calculation in the planetary habitability calculator, i.e. the incident light flux per area, weighted for human perception.

The calculator so far simply goes and uses the luminosity reduced by the inverse-square law as “illuminance”:

,

where E(v) = “Illuminance” (Suns), L(1) and L(2) = Star luminosity (Suns) and d = Distance to planet (AU).

Stars feature different wavelength peaks (Wien’s displacement law) and curves correlating with their temperature. To obtain the illuminance, we need to know not only the luminosity and temperature of the star(s) as well as the distance to the planet, but also an estimate of how much of the star’s light is in the visible spectrum. This could obviously be done by integrating over the curve but that would be beyond the scope of a spreadsheet. There must be a simpler way to approximate the proportion of visible light.

More flexible greenhouse model

So far SFCalcSheet uses the equation from idealized greenhouse model to calculate a planet’s surface temperature from its effective temperature.

Effective temperature:

T(e) = Effective temperature (K), A = Bond albedo of planet, L = Luminosity of star (W), d = Distance to star (m), σ = Stefan-Boltzmann constant

Surface temperature (greenhouse model):

T(s) = Surface temperature (K), T(e) = Effective temperature (K), ε = Atmospheric absorption (0-1)

The only atmospheric variable in this equation is atmospheric absorption/emissivity, a measure for how much radiation is retained via greenhouse gasses. Basically it only allows for modeling Earth’s atmosphere with varying amounts of greenhouse gasses. An equation that also takes air pressure would be useful for modeling worlds with a different atmosphere or a runaway greenhouse effect.

If you find something that could be adapted for use in SFCalcSheet, let me know here.