meanwhile I have incorporated quite a few more features into celestia.Sci's UI.
Here is a typical display with three toolbars activated
toolbar starting on the left, followed by the Guides
toolbar and the new Graphics
toolbar. Their separation is barely visible in this screenshot:
Besides the option of turning off some or all of the toolbars, they may also be moved according to gusto: e.g. like in this view (with the Time toolbar deactivated)
They even may be moved outside the main window space, somewhere to the desktop.
Next let me focus on a few new features:
First of all, I now display all toolbar icons by default with an increased size of 32x32 px, which hopefully reduces the guesswork about their meaning. In the preferences dialog of the menu, this may be reset to the Qt default (which is generally smaller).
A main new feature concerns the two icons on the new Graphics
toolbar. Each stands for an exclusive sub-menu
that is shown upon clicking on the black triangle on the right of the respective icon. The chosen sub-menu options are saved and restored upon restarting.
1) Choice of star color table (left):
Here one may select the desired association of the stars' surface temperatures with RGB colors. Presently, two color-temp tables are supported: The vivid
Blackbody D65 color table and the weak classical colors (that were used in older Celestia versions). I prefer the vivid Blackbody colors. The displayed icon changes with the selection made. Here are the respective screendumps:
2) Choice of DSO color scheme (right)
The options one is offered here for DeepSpaceObjects (DSO) require some explanations. Three different color schemes are available for now. They differ by the value of the Saturation S
in the HSV coior space (H=Hue, V=Value):
- Vivid DSO colors <=> S = 1
- Adaptive DSO colors <=> S increases with image zoom
- Grayscale DSOs <=> S = 0
The Saturation S, with 0 <= S <= 1, is the appropriate color-space parameter to modify the Colorfulness
of an image!
One easily derives a general formula for a RGB triplet as function of S with everything else kept fixed:
(r', g', b') = (S * r + M, S * g + M, S * b +M)
where M = (1 - S) * max(r, g, b);
At least for the two limiting cases S=1 (Vivid DSO colors) and S = 0 (Grayscale DSOs) you can immediately see that
S=1: r'/g' = r/g; r'/b' = r/b
S=0: r' = g' = b' = max(r, g, b)
In the 2nd adaptive
DSO color scheme, I let S depend on the image resolution (zoom)
or in other words on the fraction of the screensize that a given DSO occupies
. The physics idea behind this option is to interpolate smoothly between naked eye vision (no DSO colors visible) and "telescope" mode (<=> Automag!), with colors getting more perceptive as the size of the telescope increases.
Here are screenshots of the galaxy triplet: NGC 70
(blue, Sc type), NGC 71
(orange, S0 type) and NGC 68]
(orange, S0 type) illustrating the three DSO color schemes.
A color photo from the site of Prof. C. Seligman
may serve as a low resolution reference
with the resolution of celestia.Sci's NGC 70 & friends,... being much better
Note that the icons change again, depending on the option chosen...
[Click on images for true size]
A) Vivid DSO colors (S = 1)
B) Adaptive DSO colors (S increases with size scale!)
C) Grayscale DSOs (S=0)
Finally, I hope that at least some of you understand the meaning of the icons that go with the three choices. If not: Colorfulness is displayed for increasing size scale (from left to right). In the first case, colors are vivid throughout. In the second case colorfulness increases towards vivid colors with growing size scale. Last: Grayscale DSOs throughout -- for purists
Actually, in the Preferences menu that also differes much from the original Celestia-1.7.x one, one may set ANY desired value for the Color Gain
. This value determines how fast the transition from colorless DSOs to full vivid DSO color takes place when the DSO size on screen increases!
Here is the relevant menu page:
Any comments are welcome!