Release Celestia 1.4.0 final?

The place to discuss creating, porting and modifying Celestia's source code.
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t00fri
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Post #41by t00fri » 19.04.2005, 19:09

maxim wrote:That filter stuff is still just an idea - that's far from coding. I'd like to see a concept for it, and how it's supposed to be represented and controlled onscreen.

maxim


maxim,

it was much more than "just an idea". I spent quite a bit of
concrete planning into it, like I did a hell of a lot of math to
work out appropriate conformal 3d properties of a
Celestia Cosmo-display. And if I say "a lot of math" as a Pro,
it is a lot (for most people's standards) ;-) .
For the filter project, I scanned a large amount of available
data in different wavelength bands. This ranged from the
SOHO sun textures, via Titan and planetary imaging to
infra-red astronomy including the milky way (2mass)

Image
Note that the long infrared wavelength is able to
penetrate to the central star cluster of our galaxy!
Here is a small size view of the fullsize 2k original,
Image

Modern observational astronomy and space research largely
rests on exploiting multi-wavelength bands!


I suppose you (and many others) don't want to be bored here
with lots of quaternionic algebra and general relativity, for
example. Much of the more specific stuff was therefore
deferred to the developers list. Perhaps you did not follow
that in detail.

There was very intensive (and long-lasting) discussion,
except from Chris...Nothing concrete from his side, after a
long time, except some general few-line positive
encouragements.

So I gave up in frustration, since such challenging projects
require a focussing of efforts and an intensive brainstorming
among experts in different tangent fields. Notably also
concerning 3d graphics.

For me this issue is definitely dead now, after I really spent a
lot of work into it...


Bye Fridger
Last edited by t00fri on 19.04.2005, 20:39, edited 3 times in total.

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Cham M
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Post #42by Cham » 19.04.2005, 19:36

t00fri,

I may be interested in your quaternionic algebra and general relativity stuff. Could you give me more details on this ? How are the quaternions used, in relation to the conformal transformations of the metric ? This is intruiging (don't worry, I know a lot of stuff on GR, if you remember). I don't remember having saw any quaternions in GR, except through the Pauli spin matrices, and more generaly through the Dirac matrices.

I = -i Sigma_1,
J = -i Sigma_2
K = -i Sigma_3

I^2 == J^2 == K^2 = - Identity == -1

I J = - J I = K, etc...

I prefer to write

[ Sigma_i , Sigma_j ] = 2 i Levi-Civita_ijk Sigma_k

{ Sigma_i, Sigma_j } = 2 Delta_ij

etc, etc, ... You obviously know all that stuff.

What relation with the conformal transf

g_mu_nu ' = Omega^2 g_mu_nu ???
"Well! I've often seen a cat without a grin", thought Alice; "but a grin without a cat! It's the most curious thing I ever saw in all my life!"

ElChristou
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Post #43by ElChristou » 19.04.2005, 19:55

t00fri wrote:...For me this issue is definitely dead now, after I really spent a lot of work into it...


Don't be so fatalist... can you do a thread with a quick summary and the urls of the posts treating this topic?
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t00fri
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Post #44by t00fri » 19.04.2005, 19:58

Cham wrote:t00fri,

I may be interested in your quaternionic algebra and general
relativity stuff. Could you give me more details on this ?
How are the quaternions used, in relation to the conformal
transformations of the metric ? This is intruiging (don't worry,
I know a lot of stuff on GR, if you remember). I don't
remember having saw any quaternions in GR, except through
the Pauli spin matrices, and more generaly through the Dirac
matrices.

I = -i Sigma_1,
J = -i Sigma_2
K = -i Sigma_3

I^2 == J^2 == K^2 = - Identity == -1

I J = - J I = K, etc...

I prefer to write

[ Sigma_i , Sigma_j ] = 2 i Levi-Civita_ijk Sigma_k

{ Sigma_i, Sigma_j } = 2 Delta_ij

etc, etc, ... You obviously know all that stuff.

What relation with the conformal transf

g_mu_nu ' = Omega^2 g_mu_nu ???

cham,

sorry but I got definitely tired to roll that interesting stuff up
once more. Let me just refer you to a respective popular
thread of mine with 2170 readers and 54 discussion posts...

http://www.shatters.net/forum/viewtopic.php?t=4724&postdays=0&postorder=asc&start=0
or in respect to quaternions, specifically
http://www.shatters.net/forum/viewtopic.php?t=4724&postdays=0&postorder=asc&start=29


Walton (wcomer) did participate quite a bit in the (quaternionic) math of the game. Selden did plenty of practical experiments with possible display schemes of the amazing SDSS large scale structure data that are among the basic experimental pilars of modern cosmology.

Incidentally, here is Chris' only comment about the matter:

chris wrote:
On the other hand this is relatively "work intensive" and rather frustrating, as long as there is ZERO encouragement for the whole approach from Chris...
I think it's quite an interesting idea, but I'm afraid I haven't had time to reply in detail or do much else in the way of Celestia development lately. That will change in a couple days.

--Chris


Bye Fridger

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t00fri
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Post #45by t00fri » 19.04.2005, 20:34

Good News

Just got an email from Chris answering my resent email from 11 days ago.

Chris was apparently very busy professionally in the past. He definitely plans to return to Celestia development as soon as a first release of a new graphical software is done that he was in charge of developing at work.

Bye Fridger

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Post #46by ElChristou » 19.04.2005, 21:28

t00fri wrote:Good News

Just got an email from Chris answering my resent email from 11 days ago.

Chris was apparently very busy professionally in the past. He definitely plans to return to Celestia development as soon as a first release of a new graphical software is done that he was in charge of developing at work.

Bye Fridger


No date for the realease of this famous sotware? :wink:

I was reading parts of your thread (conformal mapping)... and... well... ok this kind of conversation is not for me... :oops: :oops:
...but have been done some graphical test on this? or really nothing?
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t00fri
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Post #47by t00fri » 19.04.2005, 21:35

ElChristou wrote:
t00fri wrote:Good News

Just got an email from Chris answering my resent email from 11 days ago.

Chris was apparently very busy professionally in the past. He definitely plans to return to Celestia development as soon as a first release of a new graphical software is done that he was in charge of developing at work.

Bye Fridger

No date for the realease of this famous sotware? :wink:

Definitely NO. Chris will continue to be very busy for another "while"...
I was reading parts of your thread (conformal mapping)... and... well... ok this kind of conversation is not for me... :oops: :oops:
...but have been done some graphical test on this? or really nothing?


In general concrete graphical tests are hard without having a code framework first. But Selden did quite a few tests with the Sloan Digital Sky Survey data (SDSS). On his site you can find some interesting add-ons about this.

Bye Fridger

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Post #48by PlutonianEmpire » 19.04.2005, 23:34

t00fri wrote:Good News

Just got an email from Chris answering my resent email from 11 days ago.

Chris was apparently very busy professionally in the past. He definitely plans to return to Celestia development as soon as a first release of a new graphical software is done that he was in charge of developing at work.

Bye Fridger

w00t! :D

That's definitely good news :)

I wonder what that program is? ;) It sounds cool. :D
Terraformed Pluto: Now with New Horizons maps! :D

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Post #49by maxim » 19.04.2005, 23:38

I must admit that I never really unterstood how the conformal mapping should look like in the end. And obviously I missed the developers list, and seldens practical experiments.

But for the filters I'd like to know how the display concept is. Are there fixed bands or (how?) variable ones? What happens to objects that have no reperesentation in this band? Is it supposed to be primarily for single objects or for overview situations?

maxim

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Post #50by maxim » 20.04.2005, 09:48

Ok, I got it.
Funny that I've missed the dl for so long. I'll gonna update my knowledge. Do you remember the time period when the discusion took place?

maxim

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Post #51by maxim » 20.04.2005, 17:46

:( I can't find the filter discussion in the developers list - maybe I'm dumb.

maxim

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Post #52by Evil Dr Ganymede » 20.04.2005, 19:27

t00fri wrote:Good News

Just got an email from Chris answering my resent email from 11 days ago.

Chris was apparently very busy professionally in the past. He definitely plans to return to Celestia development as soon as a first release of a new graphical software is done that he was in charge of developing at work.

Bye Fridger


Well that's good news... would have been nice if he'd said "hey guys, I'm going on a developmental hiatus for a while as work is busy" instead of leaving us wondering, but never mind.

Don't suppose he gave any idea of whether it would be days, weeks, or months until his return, did he?

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t00fri
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Post #53by t00fri » 20.04.2005, 20:00

Evil Dr Ganymede wrote:
t00fri wrote:Good News

Just got an email from Chris answering my resent email from 11 days ago.

Chris was apparently very busy professionally in the past. He definitely plans to return to Celestia development as soon as a first release of a new graphical software is done that he was in charge of developing at work.

Bye Fridger

Well that's good news... would have been nice if he'd said "hey guys, I'm going on a developmental hiatus for a while as work is busy" instead of leaving us wondering, but never mind.

Don't suppose he gave any idea of whether it would be days, weeks, or months until his return, did he?


Of course, NOT...

But he said that things would considerably relax as soon as he got out the first version of his new software.


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