Analysis of galaxies base.

[Croc]

According to the Hubble classification, galaxies are divided into:

• Elliptical galaxies
• Spiral galaxies
• Irregular or irregular galaxies

The analysis of the galaxy base will be made on the basis of the galaxies.dsc file, which contains 10,937 galaxies.
Elliptical galaxies are denoted by the letter E and the number, which is the index of flattening of the galaxy.
In the analyzed database, there are a total of 9 types of elliptical galaxies: E0, E1, E2, E3, E4, E5, E6, S0 (lenticular).
Quantitative composition of elliptical galaxies:

• E0-1503
• E1 - 57
• E2 - 44
• E3 - 50
• E4 - 27
• E5 - 24
• E6 - 20
• S0 - 3277

Total: 5002 (45.7%)

The sprite image of an elliptical galaxy is created on the basis of matrices:

The database contains 664 (6.1%) irregular galaxies. There are no special matrices for creating a sprite image of "Irr" type galaxies.

10937 - 5002 - 664 = 5271 (48.2%) remain on the share of spiral galaxies, including:

• Sa - 838
• Sb - 851
• Sc-1200
• SBa - 592
• SBb - 650
• SBc -1140

The sprite image of a spiral galaxy is created on the basis of matrices:

In the top row there are 4 left-handed matrices, in the lower row there are 2 right-hand matrices.
This is a very incomprehensible fact. There should be 6 left-handed matrices and 6 right-handed matrices. Only 12 matrices for spiral galaxies.
================================================= ==============
Summing up the spiral galaxies:

• left-handed matrices - 4029 - 76.4%
• with prograf. matrices - 1242 - 23.6%

Total: 5271 - 100% of spiral galaxies

Spiral galaxies with left-handed matrices are 3.2 times larger than spiral galaxies with right-handed matrices. : insane:: fie:

This is nonsense!

Continuation of the analysis should ...

[Croc]

Plan for the modernization of the galaxy base. Plan A.

1. Create 6 additional matrices for spiral galaxies. We change the matrix coding (see red font):

2. Make the appropriate changes to the program's algorithm.

3. Manual transcoding of the parameter "Type" in the database. Recoding order:
Spiral galaxies with a positive Z-axis value:

• Type = "SaR" is replaced by Type = "Sa"
• Type = "SbR" is replaced by Type = "Sb"
• Type = "ScR" is replaced by Type = "Sc"
• Type = "SBaR" is replaced by Type = "SBa"
• Type = "SBbR" is replaced by Type = "SBb"
• Type = "SBcR" is replaced by Type = "SBc"

Plan for the modernization of the galaxy base. Plan B.

1. We create 6 additional matrices for spiral galaxies. We change the matrix coding (see the screenshot in item 1 of plan A.

2. Make a change to the program's algorithm:
The program of spiral galaxies with a positive value of the Z axis changes the code:

• Type = "SaR" is replaced by Type = "Sa"
• Type = "SbR" is replaced by Type = "Sb"
• Type = "ScR" is replaced by Type = "Sc"
• Type = "SBaR" is replaced by Type = "SBa"
• Type = "SBbR" is replaced by Type = "SBb"
• Type = "SBcR" is replaced by Type = "SBc"

3. The database does not change.

Data plan is submitted for discussion to users of Celestia!

[LukeCEL]

I did notice that the templates for barred spiral galaxies are going in an opposite direction compared to the unbarred spiral galaxies. But instead of making 6 more templates, what if you just flipped the orientation of the galaxies using the Axis and Angle parameters? (I, however, don't really understand how those parameters work.)

[Croc]

#3by LukeCEL » 4 minutes ago
... (I, however, don't really understand how those parameters work.)

There is an opinion how to mirror the spiral galaxies:

The sum of the squares of the numbers in the Axis row is equal to 1. This is similar to the unit vector, whose starting point has coordinates (0; 0; 0). Therefore, to invert the direction of the vector, you can try to change the signs of all three numbers in the Axis line to opposite ones. Angle must be left unchanged.

Here are all the options with vector direction manipulations:
first row - inversion of values X + Y + Z
second row - inversion in pairs X + Z, X + Y, Y + Z

The desired result is not achieved.
Easier to create 6 mirror matrices for spiral galaxies
and make changes to the algorithm of the program.

[Croc]

Individual matrices for building galaxies.

In the standard galaxy base (file galaxies.dsc) there is only one individual matrix for the Milky Way galaxy:

MilkyWay.png (20.55 KiB) Viewed 14152 times

File size 120 x 120 20.5 KB

Here is the Milky Way galaxy declaration:

The Milky Way: * Galaxy" # 2 =

Code: Select all

{
        Type  "SBc"
        CustomTemplate "MilkyWay.png"
        RA         17.760278
        Dec       -28.936111
        Distance   2.772e+04
        Radius         5e+04
        AbsMag         -20.6
        Axis    [  0.4372  -0.7548  -0.4891]
        Angle     99.6995
        InfoURL  "http://www.seds.org/messier/more/mw.html"
}

And here is a sprite image of this galaxy:

An individual matrix is connected using the CustomTemplate operator.
The matrix takes up very little disk space.
If you ask the creation of matrices for irregular galaxies, then all the matrices will take about 20.5 x 664 = 13.6 MB (this is a bit).

Individual matrices can be created from photos of stars. Example, the galaxy Cartwheel. Here is a photo and a matrix:

cartwheel galaxy.png (40.16 KiB) Viewed 14152 times

Here is a sprite image created by Celestia:

Note. The matrix cartwheel galaxy.png is taken from Project "Celestia Origin", release dated August 30, 2018

Continuing the analysis should ...

[Croc]

Another example of using an individual matrix:

Note. Hoag's object.png matrix taken from Project "Celestia Origin", release dated August 30, 2018

hoag's object.png (58.97 KiB) Viewed 14150 times

.....

This galaxy was discovered in 1950 by Arthur Hog. Initially, he considered it a planetary nebula. Subsequently, Hog decided that the object is a galaxy ...

There is a great idea in the phrase highlighted in red. If Arthur Hogh could not deal with this object - is it a nebula or a galaxy?
Why not portray the nebula similar to sprite galaxies?

We must ask the developers to correct the algorithm for the formation of nebulae by analogy with the galaxies.

[Croc]

Collection of named galaxies

In this guidebook collected ~ 120 registered galaxies.
The day they need individual matrices.

Who has the desire, please send individual matrices.

[LukeCEL]

Croc (and anybody, really), here is deepsky.pl, the script used to generate galaxy.dsc files.

If anybody else can figure out how to calculate Axis and Angle values using the "orientation" subroutine, I'm all ears.

[LukeCEL]

In this guidebook collected ~ 120 registered galaxies.
The day they need individual matrices.

Some of the galaxies named in the list are rarely called that name. For example, the "UFO Galaxy" is merely a nickname, and scientists call it NGC 2683 (see SIMBAD biblio). It doesn't really require a custom template. Likewise, a lot of the galaxies in the list are dwarf galaxies named after the constellation they're in, for example the Aquarius Dwarf, Bootes Dwarf Spheroidal Galaxy, Leo T, etc. If we used a custom template, the galaxy would be flat, but dwarf galaxies are supposed to be round blobs. (Although if we had support for adding custom structures for dwarf galaxies, that would be cool.)

There are plenty of galaxies that do need templates though, some on this list and others not. Arp 147 looks much better with this template (modified from this image by NASA, under public domain):

arp147.png (66.81 KiB) Viewed 14024 times

[Croc]

Thank you, LukeCEL.

I feel that the translation using Google distorts the meaning of my message.

Added after 11 minutes 53 seconds:

#8by LukeCEL » 19.11.2018, 06:32

Croc (and anybody, really),...
If anybody else can figure out how to calculate Axis and Angle values...

We must begin to understand the concept of "Rotation matrix" https://en.wikipedia.org/wiki/Rotation_matrix