Lua Edu Tools beta version

[Cham]

So you confirm the number pad change both viewpoint and direction just like a flight simulator?

Yes. IT IS a flight simulator. No doubt about it. This is actually one reason why I designed some huge "cylindrical Cyl spaceships", with trenches full of details, so I could navigate in them like in Star Wars ! I always though this was all pretty standard in Celestia, since I knew this (and used it) since a long time already. It's usefull to inspect models too.

[chris]

So you confirm the number pad change both viewpoint and direction just like a flight simulator?

Yes, that's what I implemented. That's how I navigate when I use free-flight mode.

--Chris

[ElChristou]

Well, I really need to trash my laptop!
Hey Vince, now your Pad is just good for laptop!

[fsgregs]

Vincent:

Just tried out your latest update of the tools. They are NICE!

Two quick points ....

1. The distance boxes seem to be brighter than they used to be. Now, they look bright yellow rather than a subtle yellow. Is there a way for me to edit the Distance.lua file and dim down the brightness and color of the boxes? A pale amber would be better than the brighter yellow now.

2. You may want to remind folks that the speed with which your virtual joystick moves the screen can be changed in the main celestia.cfg file. Just locate the line that reads, "RotateAcceleration 120.0", and change it to a lower number. I like "RotateAcceleration 40.0". It swings the scene a modest amount.

Thanks for all you do!

Frank

[Vincent]

Just tried out your latest update of the tools. They are NICE!

Thanks Frank.

1. The distance boxes seem to be brighter than they used to be. Now, they look bright yellow rather than a subtle yellow. Is there a way for me to edit the Distance.lua file and dim down the brightness and color of the boxes? A pale amber would be better than the brighter yellow now.

You may want to have a look at the config.lua file. There, you can set the colors of all elements in the Lua UI. You can also define lots of other configuration parameters according to your specific needs.

2. You may want to remind folks that the speed with which your virtual joystick moves the screen can be changed in the main celestia.cfg file. Just locate the line that reads, "RotateAcceleration 120.0", and change it to a lower number. I like "RotateAcceleration 40.0". It swings the scene a modest amount.

Here again, the config.lua file lets you define the specific rotation speed of the virtual pad. This can be used on top of the "RotateAcceleration" setting for a fine tuning.

[Vincent]

29/12/2007 UPDATE :
- Added transparency and line smoothing to distance markers.
- Removed RA/Dec display -- I've added it in the Celestia standard overlay.
- Improved the text layout -- "sans10.txf" is now used as smallfont.
- Optimized the coding of the compass.

Please use Celestia 1.5pre5 to enjoy the latest added features:
http://celestiaproject.net/forum/viewtopic.php?t=11807

[ElChristou]

Nice!

[Adirondack]

- Removed RA/Dec display -- I've added it in the Celestia standard overlay.

Vincent,

why did you do that?

The Lua Edu Tools used a geocentric coordinate system and the
Celestia standard overlay (1.5.0pre5) uses a coordinate system
centered on the observer's position.
That is a difference, that should be retained.

Adirondack

[Vincent]

The Lua Edu Tools used a geocentric coordinate system and the Celestia standard overlay (1.5.0pre5) uses a coordinate system centered on the observer's position.

Ulrich,

That's true. The decision to compute RA/Dec using an observer centered coordinate system was mainly made for the following reason: using a geocentric coordinate system, RA/Dec values didn't correctly match the position of objects against the celestial grid. That was particularly noticeable when observing low-orbit satellites from the surface of Earth, or when going to a very distant star.

Do you have situations where the use of a geocentric coordinate system is specifically required ?

[Adirondack]

Do you have situations where the use of a geocentric coordinate system is specifically required ?

Well, let's take Regulus (10h08m22.3s / +11?°58'02") for example.
When you are hovering near the Earth and select Regulus everything is fine:
Celestia standard overlay: Rec 10h08m22.5s / Dec 11?°58'1.9"
Lua Edu Tools: Rec 152.09?° (=~10h08m22.5s) / Dec 11.97?° (=~11?°58'1.9")

When you 'goto' Regulus and changing the POV the values of the standard
overlay varies in respect of the observer's position (as intend).
But the values of the Edu Tools still remain the same, so you know the
geocentric coordinates even when you are far away from Earth.
I think this is a good feature, though the different units of measurement
are confusing. Maybe we should align the units of measurement to the
standard overlay.

Adirondack

[Vincent]

But the values of the Edu Tools still remain the same, so you know the geocentric coordinates even when you are far away from Earth.
I think this is a good feature, though the different units of measurement
are confusing. Maybe we should align the units of measurement to the
standard overlay.

I can add them back if you really find them useful, but I think we should keep them disabled by default. Then, displaying the geocentric RA/Dec values using the decimal format might help to easily distinguish them from the standard observer centered values:

RA: 10h 08m 22.5s
Dec: 11?° 58' 1.9"

Geocentric Coordinates:
RA: 152.09?° / Dec: 11.97?°
Dist. from Earth: xxxx ly

Are you OK with all this ?

[Adirondack]

Are you OK with all this ?

Yep, Vincent, that sounds to me to be appropriate.
Though the decimal format is confusing for beginners since such coordinates in books and so on
are given in hours, minutes, seconds and degrees, min.- and sec.-degrees.

Adirondack

[Vincent]

Yep, Vincent, that sounds to me to be appropriate.
Though the decimal format is confusing for beginners since such coordinates in books and so on are given in hours, minutes, seconds and degrees, min.- and sec.-degrees.

One one hand, the decimal degree format is shorter, and this is the way stars and DSOs are defined in the Celestia data files:

70890 # Proxima Cen
{
RA 217.429167
Dec -62.679444
Distance 4.225

On the other hand, I agree that displaying RA in hours/minutes/seconds and Dec in degrees/min/sec is more consistent both from a scientifical and an educational point of view. Since we're talking about Educational tools, I think we can go on with the latter...

[Jedi]

As for the RA, I've always been partial to the hours/seconds/minutes format.

Either way, it's a good addition to the tools. I also particularly like the smoothlines on the distance markers. You can clearly see the difference in the two.

[Vincent]

Ken,

Does the Asteroid Belt on your shot use the script with markers I posted a while ago in the forum ? Or does it use point sprites rendering ? I think it would be a good addition to the tools.

As for the RA, I've always been partial to the hours/seconds/minutes format.

Either way, it's a good addition to the tools.

I'll upload soon a version with RA in hour/min/sec and Dec in deg/arc min/arc sec, both computed using the geocentric coordinate system.

[Vincent]

I'm also thinking about replacing the timescale slider - which to me lacks in precision - with the kind of buttons that are used in Stellarium. Here's a shot of what I did so far:


The buttons respectively correspond to:
reverse time; /10, /2; real time; x2; x10; current time

For some reason, the rendering of png files in the Lua Tools is not that good...

Please, let me know what you think about that. I can also send the files for testing...

[Adirondack]

Please, let me know what you think about that.

Looks good to me.

Adirondack

[Vincent]

06/01/2008 UPDATE :
- Replaced timescale slider with active buttons that respectively correspond to:
reverse time; /10, /2; real time; x2; x10; current time


- Added back display of Geocentric coordinates:



- Added Asteroid Main Belt rendering using point sprites cmod:

[BobHegwood]

Vincent,

For what it's worth, I personally VERY much like the rendering of the
asteroid belt via point sprites. Now that looks realistic to me.

Just my Brain-Dead opinion, though.

[Vincent]

For what it's worth, I personally VERY much like the rendering of the
asteroid belt via point sprites. Now that looks realistic to me.

Bob,

Pleased you like it, thanks ! Actually, I made it using Cham's accretion disk method.
Have you noticed the difference in rotation speed between the inner and the outer
sections of the belt ? It is particularly well visible when timescale is set to 10^7...