This link seems to have very helpful information:

http://www.heavens-above.com/constellation.aspx?lat=0&lng=0&loc=Unspecified&alt=0&tz=UCT

A script to plot Right ascention and Declination, and even spot size for magnitude, translating from Ra, Dec, with spherical coordinates,
to x,y,z might help?

- Brian

Source of above information, and more: http://www.astronomyforum.net/amateur-astronomy-forum/32911-drawing-constellations.html

(http://www.rtgui.com/ links to Cartes du Ciel)

Ah, the "magnitude"... something i wasnt considering. Thanks Brian.... :)

Hey Brian. So i am going to use the pdf's you linked above to map stuff out. I also bought one of the 300 series globes to aid the setup. It will help me with converting hours and minutes to the angles i need and should help with proper scaling..... its about 4 weeks out. Gives me time to polish a few other things.... :)

The celestial math is becoming slightly less opaque.
Some references and thoughts:
http://www.heavens-above.com/constellation.aspx?lat=0&lng=0&loc=Unspecified&alt=0&tz=UCT
https://en.wikipedia.org/wiki/Spherical_coordinate_system
https://en.wikipedia.org/wiki/Celestial_coordinate_system
https://en.wikipedia.org/wiki/Celestial_sphere#Celestial_coordinate_systems

https://en.wikipedia.org/wiki/Equatorial_coordinate_system
https://en.wikipedia.org/wiki/Right_ascension
https://en.wikipedia.org/wiki/Declination

Previously in scripts, points have been plotted in Moi, using spherical coordinates converted to (x, y, z).

Star locations are available in Right Ascension and Declination, Equatorial coordinates.

Right Ascension:
RA is measured in time units of hours, minutes, and seconds.
Convert RA to degrees using 360 degrees = 24 hours.
24 h = 360 deg
1 h = 15 deg, 1 m = 15', 1 s = 15"
1 deg = 4 m, 1' = 4 s
Then convert to radians, 2PI = 360 degrees.
This radian angle is the same as Theta in spherical coordinates, mathematics version, not physics.

Declination:
Dec is measured in angles, i.e. degrees, minutes, seconds.
Dec must be converted to angle Phi in spherical coordinates.
Note that for a negative declination, minutes and seconds are ALSO negative.
Angle Phi in spherical coordinates is equal to (90 degrees minus Dec) [where Dec may be negative.]
Example: Declination of -10 degrees yields Phi of (90 - (-10)) = 100 degrees in spherical coordinates.
Convert Phi to radians.

{Note: Max kept dec, instead of converting to phi, so sin and cos(phi = dec) would be swapped}

Radius of the celestial globe, Theta, and Phi, are converted to (x,y,z) point in Moi:
var x = r * Math.sin(phi) * Math.cos(theta);
var y = r * Math.sin(phi) * Math.sin(theta);
var z = r * Math.cos(phi);

return moi.vectorMath.createPoint( x, y, z );

Point could be made into a small color circle for a large/bright appearing star. What diameter?
Add lines (great circles) connecting constellation stars.
Vernal equinox, time of day...

- Brian

http://spider.seds.org/spider/ScholarX/coords.html

Hi :)
It's very interesting task. I've wrote ~80% of the script. It took about 30-40 minutes.

Starmap.v.0.3.2015.08.23

Max,
I would love to see that....

Here is the database file. (original: http://www.midnightkite.com/index.aspx?AID=0&URL=StarChartFAQ)

Yikes! That was fast.
I see that using dec instead of phi swaps cosine and sine in getting x,y,z.

- Brian

Very cool Max!!! Wow......

If you would like to dig into this a bit, I would be willing to pay you to further customize it..... Let me know if you have time to get into it...

Thanks for the effort!
Burr

Updated version.
I thought that "mag" value is some kind of distance. I was wrong :) Fixed it.

.

Burr, thank you :)
What do you want to customize?

OK, radius of celestial sphere = distance = 50 units setting.

-Brian

Starmap + vSeed + ArrayGem :)

Hi Max,
The ability to capture a few things, and manipulate the object....

1. Create Celestial equator and elliptic equator axis. ability to move zenith per entered data, as in, set NCP/SCP rotation by degree's given and rotate NCP/SCP axis (celestial axis) by degrees (or even lat/lon coords, etc) . NSEW labels that follow.

2. Create/capture Galaxies, Nebula, Globular Cluster, Open Cluster and Visual Binary groups ( by style?)

3. Capture "magnitude data" attached to points (styles again).. Maybe a legend of 5 to -2 for size range, so 8 groups.

Seem possible?

Max,
With regard to #1 in the list above, i may not be clear on the best way to achieve the desired result, manipulating the zenith. Let me ask a couple guys more knowledgeable about it and get back to you.

Hey Brian,
"""""OK, radius of celestial sphere = distance = 50 units setting.""""""""

Can you elaborate on this statement a bit?

Currently evaluating how to set the size of the sphere in relation to the scene and camera position and view angle and get the most realistic "human" results....

Thanks.

Hi Burrman

Sorry for poor explanations.
I was just noticing that in Max's .js file, the radius of 50 is passed to the .html file using "moi.ui.commandUI.Starmap(50),"
which becomes "distance," and is used in the spherical to x,y,z coordinates.
So the celestial sphere has a radius of 50 distance units, in this case, from the center of the Earth.

Also, the cos(90 - dec) = sin(dec)
similarly sin(90 - dec) = cos(dec)
So the spherical to x,y,z coordinate equations have some sin and cos functions exchanged from the Wikipedia (Phi) equations.
There is no need to switch to polar Phi angle.
RA and Dec are also partly previously processed in the database.

Max is such a good programmer, I look to see what can be learned :-)

- Brian

Hey Brian,
I see. Thanks.