Tutorial: How to create a perfect star map for any location on Earth at any time in history

[1l2Hawk]

As a bit of a star-gazer IRL, I often get distracted in games with night maps trying to find actual constellations in what is usually just a random splatter of dots on a skybox. So while developing a game set in Egypt in 4,000 BC, a Google search of skyboxes for that turned up exactly zero matches.

In this little tutorial, I demonstrate my process for creating my own custom HDRI star map set at a specific latitude and time in history. Note: I’m using the HDRI Backdrop plugin for the sky, but the resulting texture cube can be applied to any geometry with a similar polar projection UV setup.

We employ similar techniques to create star maps for our virtual production projects as well.

ROTU - Ancient Board Games - Star Map Tutorial

[MostHost_LA]

Am I getting this right?

Whatever it is, is able to rewind time of star positions based on black magic (because we only really have data for the last 50 or so years and everything else is a guess)?

Or is it just about alinging RA to lon/lat so that you can see a static star map that happens to be peojected into a cube (since its using a cubemap)?

In elthe static star map case:

Get a sphere, flip the normals.
Unwrap it to the rugualr sphere deform (one cut longitudinal, squished poles.
Its got a special name i cant recall because… well you try remebering that and 120cpls. I definitely have buffer overflow issues in my brain

Source the star maps from nasa. All public and free to use with res up to 8k.
They also have constellations and other important stuff like a grid with numbers you can visualzie (obviously very pixxely numbers but still helpful).

Add the sphere with material in engine and scale it up to the “right” size. Now this value is a bit arbitrary. Its going to be “accurate” pretty much no matter what since the distances are astronomical, but you still want it to be big enough that it looks right.
I sugfest using a teal picture and a view from a cinecamera set to the same objective options as the picture was taken with.
You can then rotate to the specific constellation and scale up the sphere for an exact match.

With that done, dwtermine your world’s orientation - afterall unreal is a flat earth.

With the orientation, a julian date, RA, Declination, lon and lat you can then start to orient the star sphere however you need it oriented (or make a function to move it).

The end result is the real sky, as it was when photographed, for the coordinates and time you give it so that astrological non near earth objects are in somewhat accurate positions.

This however includes near earth objects (they are in the pics), so its not accurate at all if you know your science and what to look at.
Also goes back to my point about anything else being literally soecery of the darkest kind…

I got as far as positioning mars and saturn “accurately” (mathematically theoretically speaking) back in 100BC.
Stuff past that isnt really visible with the naked eye.

North star and constellations are all way way off if you go by historical accounts/drawings.
Southern cross is the closest i think.