Celestia Forums

Hi all.

I've tweaked the way the script creates the pos_table so that it steps through objects more cleanly, hopefully avoiding problems under Celestia 1.3.2 like those encountered in the early version of SolarSystemTour_v1.2.celx.

I've also added object numbering during the tour.

I've started uploading lots of Celestia deep-space objects to my web-site. I'll do a post when there are enough to make it worthwhile advertising - I've only uploaded 10 so far. I easily have 50 DSO's on my system at present, and will be making more 2D "billboard" models as Selden calls them. It is my intention to find or create a DSC and associated files for every Messier object.

Hope you enjoy the new improved script.

http://myweb.tiscali.co.uk/timmcmahon/DeepSpaceTour_v1_0.zip

Regards, Tim Mc

Looks good on 1.3.1 and 1.3.2.

-Don G.

Tim or Harald,

Since these are Deep Space Objects, and not solid objects such as planets or moons, why don't we fly INTO the objects? How would one go about modifying the script thusly:

* Approach the DSO at a slight angle (looking at the face of the picture).

* Go all the way to the center of the DSO, or close.

* Slow down more while IN the DSO.

* More rotation.

* THEN, change direction to to exit the DSO at the same slight angle approached (like a laser beam hitting a mirror at a slight angle).

Thanks a bunch guys!

Don,

Don't forget that most Nebula objects are fake. They're usually pictures on a flat surface or a slightly rippled one to make it visible from more than just straight on. Hopefully someday someone will be able to provide a fully 3D model of some of them.

Celestia has a very strong bias against taking you past a distance that it thinks corresponds to the surface of an object. It assumes all bodies are spheres and won't take you closer than an object's radius value -- which corresponds to a distance of 0.

To go into an object -- close to the surface of a flat billboard, so it fills your screen -- either the designer has to provide a small named object somewhere "inside", or you have to specify a negative distance. And this causes other numerical complications...

I'm not saying it's not possible, just more coding than a simple "GoTo".

TimMc:
Your script is excellent, and the object numbering is a good addition. As you already said, support for alternate names -and maybe partial syntax- is really necessary (I had to change almost all object names at the end lines of the script)

Selden:
now that you wrote about it:
Some time ago I downloaded a Hayden Planetarium CG animation of the Orion nebula, based on a model made from scientific 3D data:

Working with infrared and visible light observations from Hubble and ground-based imagery, C.R. O'Dell and Zheng Wen, of Rice University, USA, derived a 3D model of the inner surface of the hollowed out center of the nebula. Their model shows that the region is a wrinkled, shallow "valley," the surface of which glows from the influence of the young stars above.

So my question is: are there any scientific models of nebulae available? (no matter about the description formats, it should be possible to convert them)

Thanks in advance

Toti,

You wondered

are there any scientific models of nebulae available?

Not so far as I know.

Apparently the American Museum of Natural History has all the rights to the Orion Nebula model, and are very reluctant to make it publicly available.

Akira Inaka and John Wattie have created artistic models of nebulas and starfields, and have provided stereo images of them
(links are at http://www.lns.cornell.edu/~seb/celestia/index.html#5.3). I have not asked either of them if any of their models might be available for public use. Like the AMNH, most artists who make money from their work would be very reluctant to do that.

Howdy Selden,

selden wrote:Don't forget that most Nebula objects are fake. They're usually pictures on a flat surface or a slightly rippled one to make it visible from more than just straight on.

Of the 21 DSO add-ons I have, I think ALL of them are either rippled in some way, contain multiple images to give them "thickness", and/or contain a local starfield description. These options usually give them a bit more "depth" than a mere flat photo.

selden wrote:Hopefully someday someone will be able to provide a fully 3D model of some of them.

I would imagine this to be quite a complex task unless someone gathers field-of-depth information on these objects and their surroundings.

selden wrote:Celestia has a very strong bias against taking you past a distance that it thinks corresponds to the surface of an object.

Not when you are "flying", using the speed and navigation controls, which are also available in scripting. I *think* this is how this script functions, but I'm not positive.

don wrote:I would imagine this to be quite a complex task unless someone gathers field-of-depth information on these objects and their surroundings.

Yup. Doing it as accurately as possible is a real research project, perhaps worthy of a Master's Degree. My understanding is that it took quite a while to do all the calculations to determine the shapes of the surfaces of the portion of the Orion Nebula that was modelled.

Don / Seldon

Do you happen to have a copy of Astroboys 3D Eskimo Nebula by any chance ?
I don't know whether it's still available ?

Here's the familiar view of it, looking at it head-on;



And the next view of it, from almost side-on;



Not a bad attempt at modelling a planetary nebula. Maybe it was based on Hubble images of Eta Carinae and also the side-on Ant Nebula ?

regards
TERRIER

Hi TERRIER,

Yes, I do. This is a good example of a multi-image (two PNG images) nebula. Selden's M16 (four JPG images) is another good example.

Mustn't forget about the spherical Abell 39 Nebula either

Is that the one that looks like a partially shredded, empty shell of a planet?

Selden:
thank you for your answer.
I made a Google search on this topic, and found that several groups are working in 3D modeling of nebulae objects. Some of them still seem to be WIPs.
This page has a link to an animation of the Crab Nebula.

http://arxiv.org/abs/astro-ph/0403153

I couldn't find any downloadable data, though.

I put this script to begin,but nothing happened.I am using Celestia 1.3.1.

TimMc wrote:Hi all.

I've tweaked the way the script creates the pos_table so that it steps through objects more cleanly, hopefully avoiding problems under Celestia 1.3.2 like those encountered in the early version of SolarSystemTour_v1.2.celx.

I've also added object numbering during the tour.

I've started uploading lots of Celestia deep-space objects to my web-site. I'll do a post when there are enough to make it worthwhile advertising - I've only uploaded 10 so far. I easily have 50 DSO's on my system at present, and will be making more 2D "billboard" models as Selden calls them. It is my intention to find or create a DSC and associated files for every Messier object.

Hope you enjoy the new improved script.

http://myweb.tiscali.co.uk/timmcmahon/DeepSpaceTour_v1_0.zip

Regards, Tim Mc

I put this script to begin,but nothing happened.I am using Celestia 1.3.1.

TimMc wrote:Hi all.

I've tweaked the way the script creates the pos_table so that it steps through objects more cleanly, hopefully avoiding problems under Celestia 1.3.2 like those encountered in the early version of SolarSystemTour_v1.2.celx.

I've also added object numbering during the tour.

I've started uploading lots of Celestia deep-space objects to my web-site. I'll do a post when there are enough to make it worthwhile advertising - I've only uploaded 10 so far. I easily have 50 DSO's on my system at present, and will be making more 2D "billboard" models as Selden calls them. It is my intention to find or create a DSC and associated files for every Messier object.

Hope you enjoy the new improved script.

http://myweb.tiscali.co.uk/timmcmahon/DeepSpaceTour_v1_0.zip

Regards, Tim Mc

Hi Daniel

Check that the Galaxies flag is ticked under Render -> View Options when you are running the script. If it isn't, you won't see any deep space objects. If this doesn't fix the problem, I'll need more info about your Celestia configuration to work out what is going on.

Regards, Tim Mc

I don?t know if helps,but my Celestia is 1.3.1,not 1.3.1-1.My computer usually turn Celestia screen in a white one,and the mouse coursor usually disappear for a while.It is happening more frequently when too many things are toggled at the same time.

TimMc wrote:Hi Daniel

Check that the Galaxies flag is ticked under Render -> View Options when you are running the script. If it isn't, you won't see any deep space objects. If this doesn't fix the problem, I'll need more info about your Celestia configuration to work out what is going on.

Regards, Tim Mc

Daniel, it sounds like your difficulties running the script may be because Celestia has loaded many deep space objects with large textures (or none at all?). See the Readme document for DeepSpaceTour to explain the issues about this. The script runs fine under Celestia 1.3.1 - it does not need 1.3.1-1.
Regards, Tim Mc