Celestia Forums

I tested the current (evening of december 20) CVS version on a brand new Mac Book Pro 2.33 GHz Intel Core 2 Duo with 2 GB DDR2 SDRAM. Graphic: RadeonX1600 256 MB. MAC OS X 10.4.8.

Please notice that I'm not an expert whatsoever, so my comments are just the ones of an admirer of the program.

First of all, a few comments to the overall impression:

Several huge advancements since the may version are noticeable. The program loads faster and runs faster.
It took me some while though to disable Cloud Shadows - in a version about one week old, this lead to a very strange behaviour of Celestia*, in the current version it leads to an immediate shut down of the program.

At first sight, I thought that the view of Earth has lost some of its crispyness and that this was a bit disappointing. But after a minute or so, I realized that it looks much more like the pictures we have from space and that the new atmosphere code is indeed extremely well done. Especially when near to the surface of Earth, it looks so realistic and beautiful to look towards the edge of the sphere, seeing the landmasses disappear in the haze of the atmosphere.

The very nice galaxy rendering is nothing new anymore, but it looks like the view of the milky way from inside is now much better. Also, the possibility for custom templates for each galaxy is great to play around and I must admit that it's much more difficult than I thought before I tried it. I would really like to see the possibility for custom coloring.

Now for the downsides. I don't know which of the points that I will mention are bugs and which are just features that don't make sense to me, please appologize if I mix things that would have to been looked at separately and in another forum:

- Surely a bug is the Cloud Shadow bug i wrote about above. If needed, I can give more informations about it. But maybe it's already a known bug.

- Several bugs are reported in the forum like the glowing moons and the strange behaviour of the glow around the sun. I know "glow" is not always "glow" and maybe I use the wrong words, but for a normal user, the aprupt changes of that glowing halo depending on distance make no sense. Only when far enough the sun looks beautiful, like all the other stars. The new star rendering is really fantastic when looking at distant stars.

- The sun is really not very satisfying. When looking from Earth towards the sun, it looks very angled. When nearer to the sun, it gets better of course. When more far away, the glowing halo makes it better, too. Just from Earth distance, it looks very bad. Only with Antialiasing set to 4, it is OK. I made a screenshot on an average look from Earth. Sometimes it looks even more angled than on this picture, at least here the sun is symmetrical:



- Sunspots get brighter when you look directly on them. Only towards the edge of the sun they get darker again. I don't think this is realistic. Generally, glares and halos in the current version intensify light that is behind them rather than damp it. Per example, the milky way gets brighter behind one of these glowing moons.

- The magellan clouds look too bright from Earth. Galaxies generally look to bright. I do like the possibility to augment the light from galaxies by pressing ")", but I would also like the possibility to darken galaxies to a value near to zero. I would like to have the possibility to fade the galaxies in and out rather than having them exploding out of nowhere when enabling them.

- The orbits look very well, but the behaviour is somewhat disturbing. When I fly away from the Sun with comet orbits enabled, they disappear before I can see the whole extend of the comet orbits. Before it was possible to have one Oort cloud comet defined to depict the extend of the cloud. Now I can not even see "normal" comets' orbits as a whole. Maybe the comet orbits should not disappear collectively but individually like the planets' orbits? I would like to be able to see the orbits when distanced by a factor of at least ten to what is possible now. This is a screenshot just before the orbits disappear:



Now comes definitely not a bug, but an opinion: I would prefer stars to be drawn almost only in white when you get very near, having a strong halo that blurs the edges. The halo color of the star should show the color of the star, but the center should dazzle your eyes and therefore be white. This was already suggested somewhere else recently.

All in all, the current version is very promising. As soon as cloud shadows can be fixed, the moons stop to glow and the sun glows in a nice and smooth way, I will be extremely pleased. And there are so many more features mentioned in the forum that I really look forward to


* Info text was not shown any more, galaxies not rendered. Clouds looked distorted and sometimes only the atmosphere of a planet was drawn at all - and only at the border of the planet sphere. This was my first view of the actual development state of Celestia, and I was very disappointed. Then I disabled Cloud Shadows, but had to restart the program to enjoy the new features.

Neo, there is a problem with your picts...

ElChristou wrote:Neo, there is a problem with your picts...

What kind of? It works just as it should on my computer.

ElChristou wrote:Neo, there is a problem with your picts...

I'm able to see them.

--Chris

neo albireo wrote:- The magellan clouds look too bright from Earth. Galaxies generally look to bright. I do like the possibility to augment the light from galaxies by pressing ")", but I would also like the possibility to darken galaxies to a value near to zero. I would like to have the possibility to fade the galaxies in and out rather than having them exploding out of nowhere when enabling them.
...

A correct galaxy display requires first of all correct settings.

If we make the galaxy display too dim as a default, many newbie users will NOT find the galaxies, as experience showed!

Galaxies are difficult objects since -- on average -- we are talking about objects of 13th (app) magnitude while our default stars end at about 10th. The difficulty is enhanced by the poor dynamic range of monitors! The dimmest galaxies in Celestia are only 16th mag!

In general it is best to activate the 'automag' feature (CTRL+y) (most people looking regularly at galaxies use the automag). That implies when the FOV corresponds to naked eye view, the galaxies are very dim and you can at best make out the brightest ones in the sky. When you zoom in, however, the FOV decreases and the galaxy brightness increases along with the apparent galaxy size and the resolution of detail.

That "telescope effect" according to many users (including myself ) provides a quite natural impression of galaxies.

As I noticed during our numerous galaxy display tests, many users do not know how to correctly display the galaxies after hitting G=goto, i.e. on closer distance. Here one has to understand the crucially different functions of SHIFT+mouse_L movements versus CTRL+mouse_L. While the latter changes the physical distance the former changes the zoom/FOV keeping the distance constant. In one case the density of luminous sprites (=number of bubbles/area) remains constant while in the other case it changes, thus affecting STRONGLY the galaxy appearance. As a rule of thumb you should always combine the two mouse actions <=> distance vs zoom such that finally you still perceive some glowing nebulosity between the spiral arms. After some practicing this is very easy to achieve. Probably I should modify the GOTO command for galaxies such that the right perspective arises by default.

With automag deactivated you should set the star magnitude ('[' ']' keys) to 7-8 (NOT more). Then galaxies also look OK. Trying to display too faint stars will make the galaxies overbright without the automag.

In the recent CVS version the brightness of SMC, LMC etc relative to other galaxies are certainly OK. This has been confirmed by critical testers, recently

Last not least, it is crucial to do once a proper brightness/contrast setting of your monitor by means of special software, notably if the monitor is NEW!

Bye Fridger

t00fri wrote:Last not least, it is crucial to do once a proper brightness/contrast setting of your monitor by means of special software, notably if the monitor is NEW!

You're right that I haven't done that yet. I will do it as soon as I find the time. I had the same feeling on the old monitor though, which was properly adjusted.
However, even if the current settings are justified and scientifically accurate, I would really like to see the possibility to fade the galaxies out. A good way might be a control bar much like the one for ambient light and faintest stars, but include a button to restore the settings to "scientifically accurate". And of course, "(" then should allow for a lower setting than currently possible.

neo albireo wrote:

ElChristou wrote:Neo, there is a problem with your picts...

What kind of? It works just as it should on my computer.

Sorry, a few minutes/hour I had a red square but now things are ok.

Neo,

I agree that one should be able to apply attenuation as well as amplification to the brightness levels.

With regard to your Comet Orbit problem, however, I have no problems seeing Comet orbits out to a viewpoint distance from the Sun of ~0.1 LY (where they become smaller than the Sun's circle), and Asteroid orbits (including Sedna, etc) to a distance of 1 LY on my Windows system's Nvidia graphics card using Celestia v1.5.0pre2 -- which Chris built from the most recent CVS code. I suspect this is a Mac specific problem. Whether it's due to a Celestia coding bug, the type of graphics card you have (what is it?) or a defect in Apple's OpenGL driver, though, I don't know.

I see the same edge glitches on the Sun's image. While it may simply be due to aliasing, it seems to be somewhat coarser (i.e. at a lower frequency) than I'd expect due to my screen's resolution.

selden wrote:I have no problems seeing Comet orbits out to a viewpoint distance from the Sun of ~0.1 LY (where they become smaller than the Sun's circle), and Asteroid orbits (including Sedna, etc) to a distance of 1 LY

All orbits disappear at the same moment at a distance of about 250 AU.
When I circle around the sun, the orbits sometimes reappear when viewing the solar sytem edge-on, i.e. when I'm near the ecliptic plane. But even then, they disappear just a few AU farther away.

selden wrote:I see the same edge glitches on the Sun's image. While it may simply be due to aliasing, it seems to be somewhat coarser (i.e. at a lower frequency) than I'd expect due to my screen's resolution.

Yes, it probably is just the aliasing, but I don't remember it to ever have occured that clear. Sometimes, the sun is more a square than a circle.

Another bug found: Satellites are labelled and their orbits are colored both normally and as if they were moons:



This is now with spacecraft orbits disabled. With both moon and spacecraft orbits/labels enabled, the orbits are drawn mixed/flickering in both colours respectively.