Pulpit update

Celestia v1.5.1 is now available on SourceForge for Windows, MacOS and Linux! It fixes some bugs and includes support for many more languages. Development effort on v1.6.0 continues. If we're lucky the official release might be this fall.

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Sunday evening I managed to corrupt some of the telescope's Lua Scripted functions so everything stopped working. Since I'd done a checkin of the broken code to my svn repository, it seemed that I'd lost most of that day's work -- several hours worth :( Fortunately, I managed to find the typos and fix them in about 30 minutes this morning while doing laundry. *whew*

More functionality has been added to the simulated control pulpit.

1. The Coudé arch and Coudé axis flat are now controllable. The arch is raised and the axis flat is lowered when the telescope is used in the 5-mirror-Coudé configuration. (That doesn't actually happen any more because the Adaptive Optics' laser now occupies the Coudé room.) The design of the axis mirror assembly is loosely based on one of Russell Porter's drawings of the Right Ascension drive. I haven't located any photographs of it.

2. Indicators rotate when the control switches for the telescope's counterweights are turned on. The realtime balance meter is not yet implemented. Hopefully I'll be able to change its balance values depending on which instrument is mounted in the simulation.

3. The pulpit's illumination lamp can be turned on and off. The lamp glows but does not actually cast any light. Maybe some future version of Celestia will make that possible.

4. The pulpit's cover opens and closes. I had to take some artistic license with that. I used the same design for its open/stop/close buttons as are used for the doors of the storage rooms. Both the pulpit cover and those doors are manually controlled in real life, but simulating a pushbutton is a lot easier in Celestia.

5. As with the main control desk, the simulated pulpit has an additional "on/off" button which causes the control switches and dials to be drawn. Celestia runs about 20-30% faster when they're not drawn.



In this picture, the pulpit is on the left, while the right half shows the raised arch and lowered axis flat.

Coudé Flat Control

Implementing some of the pulpit controls has required rewriting some of the existing control functions. That's somewhat annoying, although I tried to improve them while I was at it.

The Coudé Flat controls are a good (bad?) example. The crane rotates down and places the flat on the central support column. Then it releases the flat and rotates back up again. The base of the flat is one model: it can rotate back and forth 90 degrees, between the default South-looking orientation, which reflects light toward the Coudé room, and an East-looking orientation, which reflects light toward a spectrograph in the telescope's East arm. The Coudé Flat mirror assembly is a separate model: it can either be at a fixed 45 degree tilt, for reflecting into the East arm, or it be manually or automatically tilted so it continuously reflects light toward the Coudé room as the telescope changes its Declination angle.

Previously the crane was a single model, separate from the models comprising the Coudé flat. None of the parts of the crane model moved, so in V2 its clamping mechanism passes (inappropriately) through the models of the flat when the crane rotates up after placing the flat on the central support.

However, the Pulpit includes a control for the crane's clamping mechanism. V3 now has two crane models. One of them includes a complete model of the flat, with the crane's clamping mechanism holding it securely. The other crane model has the clamping mechanism in the released position, so it'll clear the mirror's models as the crane rotates up and away. In other words, selecting the Pulpit's "place mirror" switch swaps the two crane models and changes the visibility of the parts of the mirror models that are on the support column.

I very briefly considered animating the clamp release. However, the crane has too many articulated pieces; some of them rotate, some translate and some do both. Each of them would require separate ScriptedOrbit and ScriptedRotation functions, carefully adjusted to match their motions with those of the other pieces. Maybe someday Celestia will implement animated bones (models which are constrained to stay in proximity in specified ways). Then I'll consider redoing this.

As a side-effect, I also had to redo how the Coudé flat model was controlled. That isn't entirely finished: I haven't done the code for the switch that moves control from the Pulpit to the Desk. Currently both are active simultaneously.

Here's a picture of the crane when it has just released the Coudé flat on the central support. Note the state of the Pulpit controls.

Pulpit

No, people don't give sermons here :)

Here's my start at implementing the Hale Telescope's control pulpit, which is located at the south end of the telescope. It is still missing the counterweight balancing meters and some associated labels and switches.



Oh, and its door isn't shown either, only its hinge.