Ultimate space simulation software

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SpaceEngineer
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### SpaceEngine F.A.Q.

The main Frequently Asked Questions are here
You may ask other questions in this thread.

Quarior
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### SpaceEngine F.A.Q.

The main Frequently Asked Questions are here
It is the old link, the new link is here (http://spaceengine.org/manual/faq/).

Otherwise, I post here a message but nobody answered me but the question I think it is also in this forum.
How does the coordinates in Space Engine change from XYZ to RA, Dec and Dist and vice versa ?
I tried with Proxima but without succes (see Proxima.ggb (required GeoGebra (free))) and with the version Python (see Coordinated convertor.py (required Python (free)), I just convert XYZ to Dist.
I attach my files and thank for a answer.
Coordinated convertor.zip
Coordinated convertor.py and Proxima.ggb
Have a good day.
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SpaceEngineer
Author of SpaceEngine
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### SpaceEngine F.A.Q.

How does the coordinates in Space Engine change from XYZ to RA, Dec and Dist and vice versa ?
RA/Dec/Dist to xyz:
``````x = Dist * cos(Dec) * sin(RA);
y = Dist * sin(Dec);
z = Dist * cos(Dec) * cos(RA);
``````
xyz to RA/Dec/Dist
``````Dist = sqrt(x*x + y*y + z*z);
Dec = asin(y / Dist);
RA  = atan2(x, z);
if (RA >= 2*pi) RA = RA - pi/2;
if (RA <  0)    RA = RA + pi/2;
``````
RA and Dec must be in radians, Dist in parsecs. xyz coordinates in SE are in Equatorial system (you may toggle the equatorial coordinate grid to see that).

Regarding to you question, you can't place a black hole in the exact center of the galaxy using RA/Dec/Dist, because coordinates are stored in fp32 format internally. This mean that they has only 8-9 digits precision. You may type many digits in the script (like RA 3.4681313548866251), but only 8-9 first digits will be used.

Hexadecimal format has a 3-millimeter precision across the entire Universe, but it is used only for camera.

Quarior
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### SpaceEngine F.A.Q.

SpaceEngineer: RA and Dec must be in radians, Dist in parsecs. xyz coordinates in SE are in Equatorial system (you may toggle the equatorial coordinate grid to see that).
Sorry but I don't know for find xyz with the equatorial coordinate grid :
Example with Proxima
And if I use the AbsPosition (in save-user.cfg), I have this error : ValueError: math domain error.
And with Proxima to convert RA, Dec and Dist to XYZ, I have this values :
X = -0.36132180795670715 m
Y = -1.1503733386385426 m
Z = -0.47175350706635627 m
Coordinated convertor.zip
Python code
Thanks in advance for help
Regarding to you question, you can't place a black hole in the exact center of the galaxy using RA/Dec/Dist, because coordinates are stored in fp32 format internally. This mean that they has only 8-9 digits precision. You may type many digits in the script (like RA 3.4681313548866251), but only 8-9 first digits will be used.Hexadecimal format has a 3-millimeter precision across the entire Universe, but it is used only for camera.
Too bad , I would have tried, I hope it will be corrected in the next version.
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SpaceEngineer
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### SpaceEngine F.A.Q.

Sorry but I don't know for find xyz with the equatorial coordinate grid :
Why you need this? You can't position stars in SE with accuracy of 3 mm anyway.

Mosfet
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### SpaceEngine F.A.Q.

Just a reminder for these calculations: in SE 0980, Equatorial grid displays shifted values of RA and Dec.
Attachments
"Time is illusion. Lunchtime doubly so". Douglas N. Adams
| My mods: http://forum.spaceengine.org/viewtopic.php?f=3&t=80 | My specs: Asus x555ub - cpu i5-6200u, ram 12gb, gpu nvidia geforce 940m 2gb vram |

Quarior
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### SpaceEngine F.A.Q.

Just a reminder for these calculations: in SE 0980, Equatorial grid displays shifted values of RA and Dec.
I know but isn't precise.
Why you need this? You can't position stars in SE with accuracy of 3 mm anyway.
Even if we can not set for 3 mm at the moment, for a future version, I would already have the converter Unless you plan a new way to place objects, - of course keeping the current one - due to :
``````StarBarycenter "Proxima System"
{
AbsPosition (-00000000000000005CF7B4EA659695D7, -00000000000000012819D403B042F965, -00000000000000007978254DF318A650) //Universal position
}
StarBarycenter "Sagittarius system"
{
RefBody "Milkay Way"
RelPosition (0, 0, 0) //Position relative to the RefBody
}``````
But the last time, you said it was impossible for the second option (except it was with RA, Dec and Dist).
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SpaceEngineer
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### SpaceEngine F.A.Q.

It's impossible for both options. As I had said, star coordinates are stored in FP32 format internally, so defining them as 64.64 hexadecimals has no sense. They will be converted to FP32 anyway, with loss of precision.
Second option also deals with loss of precision, because all catalog stars has a coordinate system origin in the Sun. At a distance of a center of the Milky Way, precision loss of FP32 numbers will shift black hole position by many AU. In other galaxies such shift is even more worse.

Astronaut
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### SpaceEngine F.A.Q.

And the decrease in the loading time of the planets, in which version will be added?
In such a hostile universe it is not necessary be the center to be special, just be alive

Mosfet
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### SpaceEngine F.A.Q.

Loading time can be tuned in every version and it also depends on what are the settings used, but let's consider even max settings, that's very dependent to the hardware where the program runs, so there's not really a right answer to this question.
"Time is illusion. Lunchtime doubly so". Douglas N. Adams
| My mods: http://forum.spaceengine.org/viewtopic.php?f=3&t=80 | My specs: Asus x555ub - cpu i5-6200u, ram 12gb, gpu nvidia geforce 940m 2gb vram |

Quarior
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### SpaceEngine F.A.Q.

What is or will be the difference between the version of Space Engine Steam and no-Steam ? Will it just concern that the no-Steam version will not have multiplayer mode ?
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DoctorOfSpace
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### SpaceEngine F.A.Q.

What is or will be the difference between the version of Space Engine Steam and no-Steam ?
Steam version will get more frequent updates, access to betas, and some other stuff.  Main version releases will be released on both sites, but Steam version will most likely be sold to help fund further development.
CPU: Ryzen 9 5900X @5Ghz - RAM: G.Skill Ripjaws V 64 GB (2 x 32 GB) DDR4-3600 CL18 - GPU: MSI RTX 40​90 GAMING ​TRIO 24G
Quando omni flunkus, moritati

Quarior
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### SpaceEngine F.A.Q.

DoctorOfSpace, ok. I know if it has not changed that the Steam version will be public when Space Engine will be in version 1.0.0.0 (at the moment I say this is 0.9.8.0) and I think will be more practical to update it (I mean user point of view).

Question about the site : Why the forum Beta testing is now show (or just nothing) for people who haven't in group Beta testing ? I know, it is for avoided that users who do not have this version write "anything" but at least read only as Archives (and members who are in the group of course can write).
Or maybe isn't possible in this forum to make this principle ?
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Mosfet
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### SpaceEngine F.A.Q.

I thought the beta testing usergroup was an open group, that's what it says in my user control panel: Beta testers
This is an open group, members can apply to join. In fact I applied.
"Time is illusion. Lunchtime doubly so". Douglas N. Adams
| My mods: http://forum.spaceengine.org/viewtopic.php?f=3&t=80 | My specs: Asus x555ub - cpu i5-6200u, ram 12gb, gpu nvidia geforce 940m 2gb vram |

Quarior
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Posts: 411
Joined: 11 Oct 2016 09:07
Location: Local Universe/Laniakea/Virgo SC/Local Group/Via Lactea/Orion–Cygnus Arm/Sol System/Gaia
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### SpaceEngine F.A.Q.

Mosfet, you are sure because on this forum Steam beta testers, is said :
Please do not post here if you are not a Steam tester..
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