Gaia star catalog for Celestia

The ESA's Gaia astrometric satellite has published its first Data Release, providing RA, Dec and parallax measurements for about 80% of the more than 2 million stars of the Hipparcos Tyco2 catalog. They provide RA and and Dec for another 2 billion or so stars, but they can't be used in Celestia without parallax measurements (distances). An updated DR2 is expected to be available in spring of 2018. For details, see http://sci.esa.int/gaia/

Although a 2 million star database is already available as an Addon for Celestia, most of its distances were derived using spectrographic and magnitude information and not a direct parallax measurement. As a result, they're relatively unreliable.

A revised version of Celestia's default stars.dat, containing about 110,000 stars, is available at https://www.classe.cornell.edu/~seb/celestia/files/gaia_stardb.zip  (about 2.75 MB, expands to  5.4 MB)

Revised versions of Pascal Hartmann's stars.dat containing 1 or 2 million stars are available at https://www.classe.cornell.edu/~seb/celestia/files/gaia_1_2m.zip  (about 51 MB, expands to about 59 MB)

Approximately 2/3 of the stars in each of those three stars.dat files have been updated with Gaia's distance measurements.

Interactive notebook: a WIP

I'm in the process of constructing an interactive notebook for use in Celestia, using Anim8or to design its components. It's interactive in the sense that the viewer can turn its pages, not that new entries can be written from within Celestia. Writing on a page has to be done "out of band" by painting the surface texture for each leaf of the notebook.

A sub-project was to create what looks like a taped-in photograph which will be used in several places. I have made it available on DeviantArt at http://celestiaguru.deviantart.com/art/Photo-03-taped-instant-photo-636917231

Orion's Arm Wormholes

As another distraction, I've been working on a Celestia Addon which displays the wormhole connections used in the Orion's Arm Universe

New Celestia Web site and Forum

With permission from Chris Laurel, the official Celestia Web site has been transferred to http://celestiaproject.net/

The new site is being run by a Celestia enthusiast in Russia and includes a Web Forum at http://celestiaproject.net/forum/

Algae and Fish Farming

Production of basic foods in space require plenty of sunlight as well as some gravity. While the plants and animals might not mind microgravity, production facilities work better when there's something pulling the product in particular directions. The toruses counter-rotate in order to minimize torques on the docking facilities.

ECS-5 Norway at Pell

Using Troutweaver's models, I've created a very preliminary and incomplete animation of the warship ECS-5 Norway entering the Pell system. It's about 98 seconds long. The original video is 1024x768.  By default, Youtube shows it at a much lower resolution, but if your browser has a video downloader plugin, you can download it at its full size.

 The video can be seen at
ECS-5 Norway at Pell (on Youtube)

 Here's a teaser screengrab:

Loading a Can Hauler

After a bit of struggling and letting my subconscious work on it overnight, here's an animation of a can being loaded into the hauler.

The models of the "hero" can and of the ships were created by Troutweaver.

I created the "depot" where the cans are stored while waiting for transshipment and a simplified can design to reduce graphics overhead.

The 640x480 video can be watched at
https://www.youtube.com/watch?v=vYwbla8zp08

Loading a Can Hauler

Troutweaver was kind enough to send me a few more of his models.

Here's a Can Hauler being loaded. This is a "diorama". The models (cans, pusher and hauler) are being drawn by Celestia in fixed relationships with one another. I might be able to make it more active with the pusher actually shoving cans around, but that'll take some work.

 I think the pilot of the pusher is going to catch hell from the can hauler's cargomaster. The cans are being loaded in the wrong order: they should be loaded around the circumference starting close to the engines. That way the can hauler can leave with only a partial load and not be off balance.

(I didn't think of that problem until after I'd written the "catalog" for Celestia. Changing it would be enough work that I don't feel like doing that just yet.)

Mirrors reflecting sunlight into the torus.

NASA needed a little funding help....

DSV Ringmaster

Here's another preliminary model, this time of the U.S. manned spacecraft sent to explore the Saturnian system in John Varley's book Titan. (See my previous posts.)

Cables

Gaea has a multitude of cables supporting its structure, similar to a suspension bridge. Here's a preliminary layout as seen from inside the torus. It's incomplete and incorrect, of course.

A new project: Celestia Addon for Troutweaver's models

Something a little simpler, since I don't have to make the models myself. Troutweaver's models need only a few minor tweaks, like resizing so Anim8or likes working with them and reorienting so rotations work appropriately. Here's an initial attempt, showing two of his models, Norway and Pell Station, as drawn by Celestia.

Bent, poked and stretched

It took me a while to find the scale and offset needed to persuade Anim8or's "bend" Modifier to torque a straight tube the appropriate 60 degrees. I'd made a tube with its length the same as 1/6 of the circumference of the desired torus, but most offsets for the bend Modifier kept stretching its outside circumference instead of leaving it unchanged.

Then there's the matter of keeping the spoke from being squished during the bending. Pre-stretching left it all lumpy. :(  I had to cut it off and then reattach it afterward. I think it's a little skinnier than it should be, but I'm not up to resizing it for now.

Celestia has a bug in how it draws transparent surfaces when they're regions of an single mesh which have had a transparent material applied to them: their surfaces aren't correctly depth-sorted. The workaround is relatively straightforward, though: cut them out and paste them into the mesh but leave them as separate objects.

Drawing Gaea

Infrequent posts are infrequent. :)

I've decided to try to model Gaea, a toroidal alien described by John Varley in his Gaean trilogy: Titan, Wizard and Demon. Some help with getting the sizes of its components correct was provided by someone who'd modeled it previously. In the Celestia screen-grabs below, individual components are separate meshes and have different colors. This is to help verify that the sizes are appropriate. In the final version, each 60 degree segment of the torus will be a single mesh, prodded into the appropriate shape. (Note that its mirrors are omitted for now.)

Using a rectilinear segment:

With the segment bent 60 degrees: