Ephemerides

[Sanduleak]

Thanks to the dazzling abilities of US, it is possible to produce accurate ephemerides for all kinds of astronomical bodies, even the ones with chaotic long term behavior.

The US ephemerides will be at the core of my Cinderdar Observatory project which aims at rendering a realistic representation of a ring galaxy.

For the project I made a galaxy generator for Celestia which allows me to render a little less than one million (yes: you read well... ) stars along with their planets and moons. Obviously it will not be possible to simulate the motions of such a huge number of bodies, but at least the closest ones. By 'closest', I mean to a given reference point of observation in the Rosphevron system.

Take a look of those two pictures: you see here the dual binary star systems Rosphevron (AC)-(BD). The snapshots are taken 2 years apart (2010 and 2012), from more or less the same direction in both Celestia (right side) and Universe Sandbox (left side). It would be impossible to make this with Celestia alone, because it doesn't handle the proper motions of stars. But US makes it possible, I just had to convert the Cartesian coordinates produced by US into spherical ones and feed them into Celestia.

[Sanduleak]

Following up on the ephemeris idea: rather than simulating only the star motions in a close neighbourhood of Rosphevron, I will reshape Cinderdar into a multi-rings galaxy:

• ring 0 (see picture 1): a few hundred systems about 200ly from the core, Rosphevron will be located inside this ring
• ring 1: 100k systems about 800ly from the core
• rings 2 and 3: 500k systems further away

To get the ephemerides I will only simulate ring 0 in Universe Sandbox. The stars that belong to rings 1 and more will move very slowly from Rosphevron's perspective, so I expect that if the simulation is not pushed too far away in the future, the global rendering will be realistic.

So far I have been able to modify the galaxy generator to accomodate for the new multi-ring layout. It is now able to geneate ring 0 for both Universe Sandbox and Celestia at the same time, in one shot (see last two pics).

[Sanduleak]

Rosphevron (AC)-(BD)-E star system now inserted into ring 0

(Ethel star depicted)

[deoxy99]

I don't quite understand.

[Sanduleak]

I don't quite understand.

I'm sorry if the purpose of this thread is not clear  
Let me try to explain a bit more: what I want to do is to simulate the evolution of a small galaxy as accurately as possible. I will try to provide portable data called 'Ephemerides', they are like snapshots of the galaxy at a given time in the future.

A very interesting way to use the Ephemerides is for astrometry: from the very arbitrary standpoint of a (fictuous... ) telescope at Lagrange point 5 of Orounisen-Ethel, it will be possible to make precise measures of star motions.

I hope all this will become more clear as the project moves on and as I'm able to provide more images.

[atomic7732]

Alot of names... *dies*

[Sanduleak]

A very interesting way to use the Ephemerides is for astrometry: from the very arbitrary standpoint of a (fictuous... ) telescope at Lagrange point 5 of Orounisen-Ethel, it will be possible to make precise measures of star motions.

This is the start of an explanation: when the object in red below goes from the left to the right, it makes half an orbit around Ethel star. The distance is known by Kepler's laws (it is 2*SMA).
If the object has a camera (for example, if it is a telescope), it can take a picture of a remote star in the sky at the beginning and at the end of its motion. If you compare both pictures, you wil see that the star seems to have moved in the sky, for a distance of about 2a.

From here, under the ideal case shown in the diagram, it is easy to determine the distance between the remote star and Ethel: it is D=SMA/a



For that you need to know the precise behavior of all bodies. This behavior is calculated by Universe Sandbox.

[deoxy99]

A very interesting way to use the Ephemerides is for astrometry: from the very arbitrary standpoint of a (fictuous... ) telescope at Lagrange point 5 of Orounisen-Ethel, it will be possible to make precise measures of star motions.

This is the start of an explanation: when the object in red below goes from the left to the right, it makes half an orbit around Ethel star. The distance is known by Kepler's laws (it is 2*SMA).
If the object has a camera (for example, if it is a telescope), it can take a picture of a remote star in the sky at the beginning and at the end of its motion. If you compare both pictures, you wil see that the star seems to have moved in the sky, for a distance of about 2a.

From here, under the ideal case shown in the diagram, it is easy to determine the distance between the remote star and Ethel: it is D=SMA/a



For that you need to know the precise behavior of all bodies. This behavior is calculated by Universe Sandbox.

I totally understood the diagram.

[Sanduleak]

I totally understood the diagram.

Excellent!  

Now I'm sure you will understand the purpose of the thread: the situation in the diagram only works if the whole system is unperturbated. But in reality, the ellipse around Ethel is strongly disturbed by another nearby star: Rosphevron C. Indeed the effect is so large that the red body goes much faster from left to right than from right to left! This is because due to a close encounter, it is accelerated by Rosphevron C in the former case.

If you don't take this kind of stuff into account, the pictures will be taken at the wrong dates by the telescope, and the calculated distance will be false. Only a gravity simulator can give you the proper data.

Edit: added picture showing the L5 telescope when it is far from Rosphevron C and its orbit is relatively unperturbated (orbital period 3.16 years).

Also notice how planet Orounisen stands 60 degrees ahead of the telescope, sharing the same orbit.

[deoxy99]

I wish I knew how to make your kind of systems.
Wait. I do.

[atomic7732]

(1)Now I'm sure you will understand the purpose of the thread: the situation in the diagram only works if the whole system is unperturbated. But in reality, the ellipse around Ethel is strongly disturbed by another nearby star: Rosphevron C. Indeed the effect is so large that the red body goes much faster from left to right than from right to left! This is because due to a close encounter, it is accelerated by Rosphevron C in the former case.

(2)Orounisen

(1) Thus, oscillating the orbit of Ethel. It would be interesting to see the movement of the orbit, and if it's orbit is like the tides of earth, the orbit falling right behind Rosphevron C, around it's star.

(2) Are you the person who made the Merania system, or something? I remember that name. Let me check.

Edit: Nope. I can't find it.