Visual Real Stars

[Brimfyr]

Real Stars​

Stars, planets and the Sun drawn with their real brightness, colour and position, for Kitten Space Agency. A StarMap mod.
No game files are modified. At launch the mod builds patched copies of the game's star, planet and Sun shaders and loads those instead. If a game update changes one of those shaders, it is left stock until the mod is updated. Works alongside Real Atmospheres.

Download​

Borea
SpaceDock
GitHub

Features​

Stars​

• 123,568 stars from the AT-HYG catalogue, to magnitude 9, coloured from their B−V index
• Brightness from magnitude, drawn with a realistic point spread function
• Parallax: stars sit at their real distances and shift as you travel
• Proper motion: stars are placed for the game's date and move on as time passes
• Twinkling through atmospheres, stronger and more colourful toward the horizon, following simulation time

Planets​

• Brightness from albedo, phase and distance, on the same magnitude scale as the stars
• Saturn's rings add to its brightness
• Planets and moons dim in their parent's shadow
• Twinkling reduced by apparent size

The Sun​

• Drawn as a star at every distance, at its real angular size, shrinking into the 3D sphere up close
• Sphere at its real size and photosphere colour, with limb darkening
• Dims as it fills more of the screen
• Replaces the stock sun sprite and lens flare

Occlusion and starbursts​

• Stars, planets and the Sun fade behind planets, atmospheres and vessels, and the Sun's starburst behind clouds
• Starbursts modelled on a simulation of the human eye: about a thousand fine needles with coloured fringes, on the Sun, the bright planets and the brightest stars
• A soft glow around bright sources, the eye's veiling glare, gives the Sun a corona
• The Sun's starburst comes from the part of the Sun still in view, in the colour of the sunlight reaching you
• Starbursts fade as their source is covered or leaves the screen
• The Sun's starburst is drawn over everything else
• Starbursts follow the game's lens flare setting, and the game's bloom settings no longer bury them

Screenshots​

Spoiler: Show images

Installation​

Requires StarMap. Each release is named with the KSA build it was tested on.
With Borea: install Real Stars from the mod list.
Manually:

1. Install StarMap and run the game once through StarMap.Loader.exe.
2. Extract the release into Documents\My Games\Kitten Space Agency\mods, giving mods\RealStars\RealStars.dll.
3. Launch the game once and close it. KSA adds new mods to manifest.toml disabled: set this mod's entry to enabled = true.
4. Launch through StarMap.

To uninstall, delete mods\RealStars.

Building​

deploy.ps1 builds the mod and installs it into your mods folder. package.ps1 -Version x.y.z -GameBuild vYYYY.M.D.NNNN builds a release archive in dist. Set StarMapDir to your StarMap folder. make_star_binary.py rebuilds the star catalogue from AT-HYG v3.2 (athyg_32_reduced_m10.csv.gz, in assets) and the Hipparcos main catalogue (hip_main.dat).

Credits​

• Star catalogue built from AT-HYG v3.2 by David Nash (CC BY-SA 4.0), with positions from the Hipparcos Catalogue (ESA 1997, ESA SP-1200), retrieved from VizieR (CDS, Strasbourg), catalogue I/239. Most distances and motions in AT-HYG come from ESA's Gaia DR3.
• Starbursts after T. Ritschel, M. Ihrke, J. R. Frisvad, J. Coppens, K. Myszkowski and H.-P. Seidel, "Temporal Glare: Real-Time Dynamic Simulation of the Scattering in the Human Eye", Eurographics 2009.

The code is MIT; the star catalogue is CC BY-SA 4.0. CREDITS.md gives its sources and terms.

 

[Briar Thrain]

Cool - the current star file is one that I made fyi. The devs were kind enough to use it for the time being. Yeah I get that the non realistic sizing / brightness might not be everyone's cup of tea - I like the scaling because it adds a noticeable sense of wonder beyond the solar system imho. I'll check out your mod for sure to see the difference!

The data of the current star file came from the AT-HYG catalog which combines the information of several different sources into one reference. So Hipparchos, Gaia 3, Tycho 2, etc - https://www.astronexus.com/projects/at-hyg. The magnitudes, colors via BV values, positions came from it - and then relationally tweaked.

Did you consider gamma correction values between raw converting B-V values to RGB and what the end result shown as a game display value is? Feel free to hit me up on Discord if you want.

 

[Brimfyr]

Cool - the current star file is one that I made fyi. The devs were kind enough to use it for the time being. Yeah I get that the non realistic sizing / brightness might not be everyone's cup of tea - I like the scaling because it adds a noticeable sense of wonder beyond the solar system imho. I'll check out your mod for sure to see the difference!

The data of the current star file came from the AT-HYG catalog which combines the information of several different sources into one reference. So Hipparchos, Gaia 3, Tycho 2, etc - https://www.astronexus.com/projects/at-hyg. The magnitudes, colors via BV values, positions came from it - and then relationally tweaked.

Did you consider gamma correction values between raw converting B-V values to RGB and what the end result shown as a game display value is? Feel free to hit me up on Discord if you want.

Thanks, I'm using AT-HYG for the next version's catalogue. Stars are also going to be placed at the game's start date using their proper motions and they will move with the game time. And yes, the colours stay linear all the way through rendering, with the game's tonemap and display gamma at the end.