New Demo script for Celestia 1.5

[Vincent]

Hi,

Here's a suggestion for the new Demo script:
http://vincent.gian.club.fr/celestia/demo_0.1.celx

It is based on Harald Schmidt's Solar system tour, that I've modified
and adapted to show a pulsar, extrasolar planets, galaxies and the
Universe at large scale...

[t00fri]

Vincent,

I did a test run of your/Harald's demo. I have several constructive remarks :

-- from an aristic point of view, there is a somewhat tiring repetition of movements when one after the other planet "introduces itself".

Each body emerges from the same point in space, grows, shows itself for a few moments and flies away along the same trajectory. I wonder how often I would want to watch this to the end as a normal user...

-- As to the deep space displays, I find that it looks kind of "confusing"

-- The setting of the galaxy displays are not very good indeed.
As I often wrote, one has to carefully correlate distance and FoV for breathtaking views! Since long, I plan to modify the GoTo command to take into account this important correlation.

For the Milky Way a good setting is

distance (CTRL+mouse_left): 250 Kpc
FoV (SHIFT+mouse_left): 3-4 degrees

This may be arbitrarily scaled of course!

Bye Fridger

[Vincent]

-- from an aristic point of view, there is a somewhat tiring repetition of movements when one after the other planet "introduces itself".

Each body emerges from the same point in space, grows, shows itself for a few moments and flies away along the same trajectory. I wonder how often I would want to watch this to the end as a normal user...

I agree. However, the Demo is mainly intended for new users. I think that the "boring" effect will be less striking for them than for experienced users... Then, a work around would be to fly beside small objects (Moon, Toutatis,...) without stopping nor centering the view on them.

-- As to the deep space displays, I find that it looks kind of "confusing"

Are you talking about the final large scale view with galaxies marked ? I can try to change the point of view, if this is what you mean.

-- The setting of the galaxy displays are not very good indeed.
As I often wrote, one has to carefully correlate distance and FoV for breathtaking views! Since long, I plan to modify the GoTo command to take into account this important correlation.

Yes, I had the same feeling. I'll try to adapt distance and FoV to get a nicer rendering of galaxies.

Fridger, thanks for these very constructive remarks.

[selden]

It's always good to have a concrete example to argue about

I think there are two primary types of demos one can do:
1. a demo showing what Celestia can do
2. a demo showing astronomical objects using Celestia.

This seems to be type #2.

I'm biased toward having a demo script of type #1. This one seems too much like a slide show. Slide shows can be implemented without using Celestia.

Specific issues that I have with the script:

I think there should be text at each step describing what Celestia is doing and what capabilities the script is making use of.

The pauses between showing interesting objects are too long. It feels as if most of the time is spent with the screen black, and too little time with something visible.

If one selects the demo while Celestia is not running, it starts with the Sun filling the screen. It probably should start with a more interesting viewpoint, perhaps one similar to the splash screen.

[t00fri]

-- from an aristic point of view, there is a somewhat tiring repetition of movements when one after the other planet "introduces itself".

Each body emerges from the same point in space, grows, shows itself for a few moments and flies away along the same trajectory. I wonder how often I would want to watch this to the end as a normal user...

I agree. However, the Demo is mainly intended for new users.

I think new users need special "care" and motivation ...and as Selden emphasized probably also an explanatory text with each new motiv.

I think we have always been struggling in the Celestia community to present graphical displays to the public that are also pleasing from an artistic point of view!

Remember e.g. those long struggles about which SPLASH image with which font we should choose or which color palette would be both color-harmonic and functional etc.

Bye Fridger

[Vincent]

OK, let's start again from scratch.
I'll try with something more... personal...

[Vincent]

I think there are two primary types of demos one can do:
1. a demo showing what Celestia can do
2. a demo showing astronomical objects using Celestia.

I think that Selden has a very good point here: before spending some more time on writing another script, it would be nice to get more opinions about the content of the demo script . Here are some suggestions about what should be shown in the script:
1- All Celestia features ?
2- The most important Celestia features ? Which are they, in that case ?
3- An example of object for each type of astronomical objects that are included in the standard Celestia database ?
4- The most important objects for each distance scale (solar system, stars, double star systems, exoplanets, Milky Way, local group, other galaxies, universe at large scale ? This is roughly what I intended to do in my first try.
5-...

I think new users need special "care" and motivation ...and as Selden emphasized probably also an explanatory text with each new motiv.

I think we have always been struggling in the Celestia community to present graphical displays to the public that are also pleasing from an artistic point of view!

Yes, These are also very valid points to raise:
- Should the script display some text ?
- Until which limit should we focus on the artistic side ? I mean, should we only display the most pleasant objects from an artistic point of view ?

Of course, the more opinions we'll get on these points, the more chance we'll have to write a nice and efficient demo script that will satisfy the majority of users...

[ElChristou]

In all case I suppose the demo should be a kind of teaser...

[rwill]

I think there is one more important purpose of a demo script that hasn't been mentioned, and that is demonstrating scripting itself. Fortunately, the kind of variation and artistry that are desirable from the point of view of entertaining a passive viewer and showing off the capabilities of Celestia will also tend to exercise the script code so that it is naturally full of useful examples. A demo.celx would be a great addition too, and could allow different goals to be achieved without trying to squeeze too much out of one script.