Follow-up: Create a new sky based inspired by...

This exercise was originally posted at: http://maritimeorca0.blogspot.com/2012/08/create-new-sky-based-inspired-by.html

The Task

Create a fictional sky with at least two galaxies, two star clusters, and one nebula influenced by the random word/phrase provided.

Random Word/Phrase

Charles Messier
 

My Creation

I actually created two different versions of a new sky. The first concept was simple. I took the free image editing program, Paint.Net, and created 15 layers that had noise (4 Intensity, 0 Color Saturation, 100.00 Coverage). I manipulated these layers to have transparent background (except the bottom layer, which has a black background) and replaced each pixel of noise with a level of gray/white for the noise (higher layers are darker).

2 Layers	15 Layers

I then randomly selected 5 stars on my second brightest layer (Called "E" and having stars with a hexadecimal RGB code of EEEEEE). I added one more layer to identify the five selected objects with a semi-transparent red highlight and red text.

2 Layers	15 Layers

The problem with this approach is that it does not properly represent the apparent curvature of the sky (in comparison to a home world or wherever the sky is being viewed). Since there is no curvature in this approach, the ends should not be combined. This means that there is nothing wrong with adding more sky above, below, or to the sides. Since the sky can always be expanded, I am referring to this creation as "Infinite Sky." The original file can be downloaded at https://skydrive.live.com/redir?resid=2E6EFB80915ED5BD!3899

My second concept was meant to better reflect reality. I created locations in Excel for the five objects in question. I started with a simple challenge. How do I randomly define the location of an object. I decided to start with a simple XYZ representation. Since I wanted a degree of realism, I also added a distance component. I determined the furthest distance that I should accept for each object (60,000,000 ly for galaxies, 100,000 ly for star clusters, and 10,000 ly for the nebula) would be entered into cell G1. Since that distance should be used in calculations in each direction (not just positive), I used the formula =RAND()*$G$1*2-$G$1 for X and filled to the Y and Z columns. I also calculated the final distance with the formula =SQRT(A2^2+B2^2+C2^2). If the total distance exceeded the maximum that I would allow, I recalculated. When I found coordinates that met my criteria, I copied the values to the rows below.

Once I had the random coordinate, I copied them to a new table in my Objects worksheet. I identified the objects with simple codes. G1 and G2 are the galaxies. C1 and C2 are the star clusters. I also added fields for Inclination and Azimuth calculated as =ACOS([@Z]/[@r])*(180/PI())-90 and =ATAN2([@Y],[@X])*(180/PI()). Now that I have legitimate coordinates for a more realistic sky, I converted the information to X and Y coordinates. I am using a 360x360 image. Using the formulas =INT([@Azimuth]+180) and =INT([@Inclination]*2+180), I had a quick calculation of where each object should be in the image. I have a layer with the black background and stars. I have also added the layer for labeling the objects. The five objects are as follows:

ID	Object Type	Distance	Inclination	Azimuth
G1	Galaxy	51,397,487.61	6.12926	134.31701
G2	Galaxy	39,971,179.01	-8.18672	92.49895
C1	Star Cluster	95,062.37	13.97224	81.00552
C2	Star Cluster	102,022.74	33.72569	-159.48831
N1	Nebula	7,759.48	6.12219	108.65809

Inclination and azimuth are roughly measured in degrees. Inclination in -90° to 90° while azimuth is -180° to 180°. My Excel file can be downloaded at https://skydrive.live.com/redir?resid=2E6EFB80915ED5BD!3897
And my Paint.Net file can be downloaded at https://skydrive.live.com/redir?resid=2E6EFB80915ED5BD!3898
Here is an image showing a rough location of the five objects:

 

Notes

Although I do not currently have plans for further exercises based on a fictional sky, I will not rule out the possibility. I should point out that I could have filled in stars for my second solution, but I felt that it would be repetitious reuse of my formulas. The mental involvement would have been fairly insignificant, and it did not seem worthy of the significant demands to time and effort. I should also point out that West and east could be confusing since you are looking up at the sky rather than down to the ground. If North is at the top of your perspective, West and east would seem reversed.
 

Feel Free to Comment

Now that this exercise has concluded, feel free to share any thoughts that you had regarding results, your approach, and any other ideas that popped in your head regarding this exercise.

About Sharing

Anyone referring to my specific creation should give me credit. I will not demand credit for any creation that has been built on my formulas. Unless otherwise specified, similar guidelines should apply to creations from other contributors.
 

Upon completion of this exercise, please fill out the following form:
https://docs.google.com/spreadsheet/viewform?formkey=dGpibFcwdW1qcUhQTTdIcnoxOXpZd2c6MA
Responses to the above form are collected and stored in a spreadsheet that can be viewed at:
https://docs.google.com/spreadsheet/pub?key=0Agcdh--NHOS0dGpibFcwdW1qcUhQTTdIcnoxOXpZd2c&output=html