Motherlode Peer Group Review

[BobHegwood]

Just to make MY case though, here's an image of M31 as it appears
in both Celestia 1.4.1 and 1.5 Pre5 via the add-on (left) and
Celestia's internal rendering (right)...



This is what you see when you type in either "M31" or "M 31." I'll keep
these add-ons on the ML, but I still think it's a mistake to do so.

Just my opinion though.
Others will be deleted because they intersect Celestia's renderings
at right angles, and these WILL be deleted.



Thanks, Brain-Dead Bob

[selden]

Bob,

I agree that Jestr's M31 addon leaves a lot to be desired. (That's a euphemism. ) It looks just as bad in v1.3.2. You might try contacting him to ask if he'd like to provide updated versions of his Addons. His modelling abilities have improved somewhat since he created that one.

[selden]

Bob,

Please don't forget that the flat billboard models are drawn in the plane of the sky. They're designed to be viewed from the same viewpoint where the photograph was taken -- from the Earth. They aren't designed to be inspected from any other viewpoint. If it's a picture of a spiral galaxy that we see edge on, the image is supposed to be perpendicular to the plane of the galaxy blob drawn by Celestia's deepsky.dsc.

It would be appropriate to include a note to that effect for such an Addon, but, by itself, I don't think it's a reason to discard it.

[abramson]

Much better than this would be a script to extract, from mpcorb.dat, asteroids according to criteria.

Hi, all. I did it. I wrote a PERL script that reads MPCORB.DAT (the offcial table of asteroids orbital elements published by the Minor Planet Center of the IAU) and converts its data to .ssc format, to be used in Celestia. The asteroids can be filtered by several criteria. It's interesting. I uploaded it to my page: http://cabfst28.cnea.gov.ar/~abramson/celestia/mpcorb2ssc.zip. I will appreciate comments and suggestions if anybody tries it.

It would be even better to use a celx and paint the asteroids in different colors or with different symbols. But I do not speak celx. Even, forgive my PERL, it has a strong FORTRAN accent!

I am posting this also in some other thread of its own, so please do not answer here, since it actually belongs to a different topic.

Cheers,

Guillermo

[t00fri]

When examining galaxy add-ons, PLEASE keep only those that have an AbsMag entry in their data section!!! Otherwise the results will be FAR too bright and devs will vast their time looking for malfunctions...

I would guess that Jestr's M31 does NOT have an AbsMag entry.
You may always ask the creators to add AbsMag in later. Modern Celestia WANTS AbsMag.

Bye Fridger

[BobHegwood]

When examining galaxy add-ons, PLEASE keep only those that have an AbsMag entry in their data section!!! Otherwise the results will be FAR too bright and devs will vast their time looking for malfunctions...

I would guess that Jestr's M31 does NOT have an AbsMag entry.
You may always ask the creators to add AbsMag in later. Modern Celestia WANTS AbsMag.

Bye Fridger

Sorry, but I STILL do NOT understand why anyone would wish to
keep these add-ons. At the very BEST, they cause rendering of the
same galaxy in two different places.

I honestly do not understand why anyone wishes to keep these
things. WHY do we wish to render TWO versions of the SAME
galaxy?

This is driving me NUTS! Or, nuttier...
Sorry, just do NOT understand. Celestia's internal location engine
simply has to be doing a better job of locating the things for
a 3d perspective, and I don't know why you'd want to screw
this up with another, poorer (and flat) representation of the
internal renderings.

As to the AbsMag entries, what the hell difference does it make?
If the flat panel PNG file features a BRIGHT image, then that's
what you'll see in Celestia. Does this have to do with the
galaxy's location in space? Some calculation I'm not aware of?

[BobHegwood]

Another Example:

This is Jestr's M33 Galaxy:



This is an example of the right-angle galaxy representation I was
referring to in an earlier post. Do you people REALLY wish me to keep
this on the ML? Again, Celestia's rendering is in the background and
it's separated from Jestr's flat 2D model in the foreground.

Beyond comprehension...

[Johaen]

Do you people REALLY wish me to keep
this on the ML?

While I haven't seen them all, ones like that, where it's not even close to the same, even when viewed from earth, should either be fixed or deleted. Something that inaccurate does not belong on the Motherlode.

[cartrite]

Hey Bob,
If you press the "@" key and hold down "shift ctrl". You can spin the galaxy around and orient it right with the mouse. Holding down the left or right mouse button spins the galaxy differently. There used to be a way to send the orientation to a log but the option --verbose doesn't work anymore. These both are taken by the m33 addon you mentioned above.




The m33 addon is using Nebula and if you change that to Galaxy, it looks oriented right but is all white and too bright. I wonder if there is a key that toggles galaxy rendering.



The first "semi" fix is simple really. Maybe you can make that note and attach it to the add on description. I took these screen shots using a recent cvs build.

cartrite

[selden]

If you press the "@" key and hold down "shift ctrl". You can spin the galaxy around and orient it right with the mouse. Holding down the left or right mouse button spins the galaxy differently. There used to be a way to send the orientation to a log but the option --verbose doesn't work anymore.

It works fine for me.
It works only for SSC and DSC objects, not for Stars. Grant Hutchison's spreadsheet is more accurate, though.
http://www.lepp.cornell.edu/~seb/celest ... sheet.html



Start Celestia from the command line with
two hyphens in front of verbose
and direct the output (>) to any log file name you want.

In other words, in a Command or terminal window, type the command
celestia --verbose > filename.log

While Celestia is running:

+ Shift-2 (@) = toggle orientation edit

+ Select the object to be reoriented


+ Move mouse while holding down Ctrl-Shift Left mouse button to adjust X and Y rotation angles

+ Move mouse while holding down Ctrl-Shift Right mouse button to adjust Z rotation angle (DSC objects only)

+ Shift-1 (!) = write the current orientation of the Selected object to the log file.

+ exit from Celestia

+ inspect the contents of filename.log (a plain-text file)

The lines starting with Orientation:
display the Axis and Angle values to be used.
Be sure to delete the commas (,) from the Axis description when you paste it into your SSC or DSC catalog file.

[cartrite]

selden,
Everything you posted works for me except the --verbose. When I put "./celestia --verbose >align.log" on the command line, a blank align.log is created and celestia doesn't start. I get a message that says

Code: Select all

./celestia --verbose >align.log
celestia: Unknown option '--verbose'.
celestia: Use --help to get a list of available command line options.

I was using the kde version when I did this.
EDIT:With the Windows version everything works. I guess I need to replace --verbose with something else in the kde version.
cartrite

[BobHegwood]

Hey Bob,
If you press the "@" key and hold down "shift ctrl". You can spin the galaxy around and orient it right with the mouse. Holding down the left or right mouse button spins the galaxy differently. There used to be a way to send the orientation to a log but the option --verbose doesn't work anymore. These both are taken by the m33 addon you mentioned above.
The m33 addon is using Nebula and if you change that to Galaxy, it looks oriented right but is all white and too bright. I wonder if there is a key that toggles galaxy rendering.

I should have to do NOTHING to use an add-on that is correctly
built. Simple. But, since people do wish to keep the things, I'm simply
adding helpful text to the file descriptions. <shrug>

Thanks for the information though.

[cartrite]

Hey Bob,
If you press the "@" key and hold down "shift ctrl". You can spin the galaxy around and orient it right with the mouse. Holding down the left or right mouse button spins the galaxy differently. There used to be a way to send the orientation to a log but the option --verbose doesn't work anymore. These both are taken by the m33 addon you mentioned above.
The m33 addon is using Nebula and if you change that to Galaxy, it looks oriented right but is all white and too bright. I wonder if there is a key that toggles galaxy rendering.

I should have to do NOTHING to use an add-on that is correctly
built. Simple. But, since people do wish to keep the things, I'm simply
adding helpful text to the file descriptions. <shrug>

Thanks for the information though.

True. But maybe it did work in 1.3.2 or 1.4.1 and it doesn't now. I don't know. This is the first time I tried it. Did you ever try to contact Jestr?
cartrite

[cartrite]

Maybe I did try it long ago and forgot. Back in the day when I first started to use Celestia, I used to download a lot of Galaxies and Nebula from the Motherlode. But I didn't like what I was seeing which led me to start creating my own addons.
cartrite

[BobHegwood]

True. But maybe it did work in 1.3.2 or 1.4.1 and it doesn't now. I don't know. This is the first time I tried it. Did you ever try to contact Jestr?
cartrite

I have not heard from, seen, nor tried to contact Jestr. If he doesn't
wish to participate here, then he obviously does NOT wish to be
bothered with Celestia. Not my place to bother him, and I will NOT.

Sorry, Bob

[BobHegwood]

Just FYI...

Even though I absolutely hate the things, I have updated all of the
installation instructions and left on the ML all Billboards up to and
including the Messier Nebulae in the Extra-Solar category of the ML.

Will be finishing with these things shortly as I get the time to do the
remaining NON-Messier Nebulae section of the category.

Again, this is just FYI.

Thanks, Brain-Dead

[BobHegwood]

Next candidate for deletion is Selden's dsc file located on the
Motherlode.

The description says it all, and I quote "This catalog is obsolete and
should not be used with Celestia v1.4.0." If it's obsolete for Celestia
1.4.0, then it must surely be obsolete for Celestia 1.4.1 or later.

Comments? Selden?

EDIT: Deleted after discussion with Selden.

[BobHegwood]

Another potential deletion.

This is Angry Space Goat's Celestial Semisphere.
This add-on contains absolutely NO installation instructions, and I
cannot get the thing to work no matter what I do. Does anyone know
how to make this thing work correctly?

If not, will be deleted.

EDIT: Comments below good enough for me, so this add-on is now Deleted.
Thanks John and Selden.

[John Van Vliet]

hi bob Angry Space Goat's Celestial Semisphere hangs
the new small stars.dat crashes celestia 1.4.1 and cvs build as of {Wed 19 Dec 2007 01:00:25 AM EST} so i would say get rid of it

[selden]

It's unusable with v1.5.

The format of stars.dat has changed since that Addon was created. ASG hasn't posted here since December, 2005, so I suspect he isn't doing much with Celestia any more and is unlikely to be able to update it. You might try sending him e'mail, I suppose.

My vote: Delete it.