Latest Sky Astronomy Update Observations/Suggestions

[IronOre]

Astronomy is my scientific specialty, and the changing rise/set angle of the sun and movement along the horizon was one the the main reasons I was attracted to Vintage Story.

Needless to say, When I first started playing I conducted an in-depth astronomical analysis and confirmed the EXCELLENT behavior of the sun, but of course I was quite confused by the moon and stars before the recent update.

Previously the moon was rising the west and setting to the east and while that would be possible if the moon was moving VERY fast relative to the spinning of the earth, the illumination of the phases made no sense. It also  always used to rise/set at the same place on the horizon no matter the latitude at a position just south of due E/W.

The stars used to be globally static for a slight southern hemisphere location where they would rise in east slightly up and to the left, set in west slightly down and to the left.  The celestial poles were always near the north/south horizons with South Celestial Pole a bit above the horizon and the North Celestial Pole a bit below the horizon.  At the time the stars would rotate once per day to always come back to the same midnight configuration.

When I saw the release notes for the v1.21.0-pre.1 - Story Chapter 2 Redux update, I was very excited to see the following:

Moon and stars position now closer to a real astronomical simulation

Moon phase now consistently correct
Rendered moon orients itself so that the lit side precisely faces the sun current position
Moon phase is correct based on relative moon and sun positions
Moon apparent path through the sky is now close to the ecliptic
Night-time star field rotates appropriately for the current latitude
Night-time star field varies over the calendar year according to the seasons / zodiac*

MOON 

Everything I was hoping for was addressed in the update.  I was over the moon (pardon the pun)!  When I got the update I went in to make new observations and I was so happy to see all the things mentioned for the moon working.  I thought it might look a little better if the moon phase shadow would curve a bit to show a crescent phase instead of a straight line, but that is a minor issue and one I could totally live with in a voxel world.  I want to be clear that I am thrilled with all the work put into this and to give a big thank you to all those involved.  I just wanted to make this post to say that, and to suggest a few tweaks for the future, and I'm happy to help in any way that I can.  I study this stuff so it is a lot of fun for me!

STARS 

The main thing that didn't match the update plan was for the star field to rotate appropriately according to latitude, and I was very confused when I got in and made my initial observations.  While the stars now do shift through the seasons as the update planned (*though they might be going the wrong direction unless this planet is in a retrograde orbit relative to the direction it spins), there seems to be an issue with rotating the star field correctly for the latitude.  For almost all latitudes they are still rising up and to the right as you look eastward and this only changes after around 66 S (when this should be more and more vertical as you approach the equator where they should rise and set straight up and down (perpendicular to the horizon), and then start to rise up and to the left at steeper and steeper angles as you look eastward for all the southern latitudes until moving parallel to the horizon at the poles.

Currently at the north pole (90 N) the stars should be rotating with the center position (north celestial pole) directly overhead and the stars near the horizon going around the horizon without rising or setting. Strangely the only place this happens is around 66 S.

At the equator (0) the stars should be rising and setting straight up and down perpendicular to the horizon.  Strangely this is occurring at around latitude 23 N.

At the south pole (90 S) the stars should be rotating with the center position (south celestial pole) directly overhead and the stars near the horizon going around the horizon without rising or setting. Again, strangely the only place this happens is around 66 S.

I think what is happening is that the sky is not spinning around a fixed point but the actual center points (celestial poles) are shifting, but not quite to a pattern I can determine.  To fix  this all that would be needed is to spin the star sphere such that just 2 points seem fixed (north and south celestial poles) and then tilt the star sphere according to latitude just as is done with the sun.  This would shift the north celestial pole from directly above at the north pole (90 N) which would drop to the northern horizon at the equator (0) where the south celestial pole would start to be visible on the southern horizon.  From there the north celestial pole would drop below the horizon, and the south celestial pole would start to be higher and higher above the horizon until it was directly above at the south pole (90 S).  In other words, the stars should rise and set at the same angle as the sun for all latitudes.

My only other suggestion would be to have slightly more exaggerated/recognizable constellations (not real ones, but something cool) as the star field is very busy and nothing really stands out.  There could still be a lot of fainter stars, but some bright ones to form various patterns could contrast with the fainter background stars.  Barring that, at the very least it would be nice to have very clear (large/bright) polar stars, maybe a red one for the north pole and a blue one for the south to help pick them out for visually checking latitude at night.

[Єгорія]

Does this mean i can track my lattitude by finding the angle of the sun/moon plane of movement?

[EmperorPingu]

On 8/29/2025 at 3:56 PM, IronOre said:

(*though they might be going the wrong direction unless this planet is in a retrograde orbit relative to the direction it spins)

Haha! Yes, I found this too lol:

 

On 8/29/2025 at 3:56 PM, IronOre said:

(when this should be more and more vertical as you approach the equator where they should rise and set straight up and down (perpendicular to the horizon)

Are we talking about the axis of rotation for the starfield (as viewed from the player)? It would be paralel to the horizon then at the equator then surely?!

[EmperorPingu]

15 minutes ago, Єгорія said:

Does this mean i can track my lattitude by finding the angle of the sun/moon plane of movement?

~ish. The devs have said they've implimented this but from my own observations it's a little rough and not what you might expect. For example - if you do some fancy maths you can figure out where the equator and the poles are, but the celestial bodies don't behave how they should at specific locations.

[Єгорія]

5 minutes ago, EmperorPingu said:

~ish. The devs have said they've implimented this but from my own observations it's a little rough and not what you might expect. For example - if you do some fancy maths you can figure out where the equator and the poles are, but the celestial bodies don't behave how they should at specific locations.

So it is useful, but it's not directly translatable from real life? That's okay i think

[IronOre]

@Єгорія 

The way it is currently working (unless they changed it since I last looked) it wouldn't be very useful unless you just matched it up to the somewhat random pattern I outlined.  It wasn't like it was just offset or anything, the correct behaviors were matched up in different ways with the wrong latitudes.  What you could currently do is measure the shadow at midday and match it up to a table for different latitudes at each time of year, or also the angle/range of rising and setting positions on the horizon over the course of the year since those both are functioning in a more or less realistic way, but if you are working from scratch you'd have to get all the data together first (or like mentioned above if you had the variables you could do some math).  That would yield decent functionality to an extent but might be unwieldy for some purposes.  Still early navigators used all sorts of methods and it could all be fun!

@EmperorPingu

You are right if you mean that the axis of rotation is flat at 0 degrees along the horizon, with the points around which the axis rotates sitting directly north and south on the horizon from the point of view of the player.  I was talking about the angle of rise/set for the stars.  At the equator, if you look due east, the the stars in that direction will seem to rise straight up from the horizon, arc overhead, and set straight into the western horizon.  As you look more toward the north or south those stars will seem to rise/set in a curve more and more around the north and south celestial poles, and every star will trace out a smaller and smaller half circle in the sky, spending half the time of the Earth's rotation above the horizon, and the other half below.