Thursday, May 29, 2008

Alpha test?

I think this project is about 90% completed, but you know what they say: the last 10% takes 90% of the time ;)

There are lots more things to do, but all of the major functions have been implemented.

If anyone is interested in giving it a try, please make a comment here. I can make it available for anonymous download, so you don't have to provide an e'mail address if you want to preserve your anonymity.

Size:
o Addon Zip file: 16.5 MB, expands to 74MB on disk (cmod model files aren't very compact); Celestia + telescope with control desks is about 250MB when fully loaded into RAM.

Performance:
o 15-20fps on a 3.4GHz P4-550 + Nvidia 7800GTX

I'd be interested in knowing what kind of performance is seen on other systems. I fear it may be unacceptably slow on many configurations. :(

Tuesday, May 27, 2008

Minor bugs

Not much to report for the long weekend: I only fixed a few minor bugs which don't have much effect on what's visible. E.g. the transfer of manual orientation commands to the telescope wasn't working right. I'd left out an if statement.

Thursday, May 22, 2008

coude flat frustrations

The central Coude flat supposedly can be controlled manually. Presumably this is necessary when using the telescopt in the 5-mirror coude configuration so that the central flat reflects light to the mirror in the Coude arch. Its angle has to change as the target changes in declination.

Unfortunately, I don't see any controls on either control desk which can actually change that angle. I started to implement one of my own (using a little artistic license :) ). I even got so far as to create an indicator dial with fiducial marks. I then realized that to do it with enough precision would require 3 (or 6) dials, just like the controls for the telescope itself. I then gave up on that idea. For now I expect to only implement the "automatic" mode and let the mirror change its own angle. (or not).

What else? Oh, yeah, I added some details to the description of the Easter Egg. That text is all encoded rot-13, so its easily decoded, but not readable at first glance.

I also started implementing the code for the RA Rate meter. It shows how fast the telescope is moving in RA in seconds of RA per hour. The guage has a selectable maximum value of 300 or 3000 sec/hour, so it obviously can't show the absolute speed, which would be about 3600 sec/hour. I'll assume it's supposed to show the difference from that.

Monday, May 19, 2008

Easter Eggs

I spent some of the weekend implementing an Easter Egg: an undocumented feature that you have to hunt for. It's not much of a puzzle, but it's something people have asked about several times on the Celestia Forum. I have an idea for another one, although that one is more of a rotten egg than a painted one ;)

Thursday, May 15, 2008

balance meter


I've done about half of the work to add the balance meter and associated selection switch. Still to do are to illuminate the balance lights, label the meter and make the switch and meter move.

Tuesday, May 13, 2008

moderated comments

Please make comments!

I've changed the comment requirements from registered Blogger users to anonymous but moderated. I hope I don't regret this.

One person mentioned to me that he didn't make any comments here because he didn't want to register for yet another account that he'd never use again. Allowing only registered Blogger.Com accounts was an attempt to minimize spam. Spammers are (I hoped) unlikely to have Blogger accounts. By changing it to allow moderated anonymous postings, people without Blogger accounts can post comments, but they won't be seen by anyone but myself until I OK them.

Monday, May 12, 2008

buttons, buttons.

I didn't accomplish much this weekend: I only added a couple of unlabelled/nonfunctional buttons to the pulpit and holders for its lamp. No pictures.

Tuesday, May 6, 2008

Observing at the Cassegrain focus


Last evening I spent some time on the observer's platform that used to be used some years ago when people visually guided the telescope while recording data at the Hale Telescope's Cassegrain focus.

p.s. Although it isn't obvious in the picture above, the simulated observer's platform automatically follows the Cassegrain focus around, elevating the little green man as necessary. I've briefly considered implementing manual steering controls, but have tentatively decided it'd be too much effort for too little gain. At any rate, in the picture below, he's photographing Neptune.

Monday, May 5, 2008

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.


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.