It is currently Fri, 21-07-17, 18:46 GMT

All times are UTC




Post new topic Reply to topic  [ 30 posts ]  Go to page 1, 2  Next
Author Message
 Post subject: Questions and help
PostPosted: Fri, 13-09-13, 19:10 GMT 
Offline
User avatar

Joined: Tue, 04-09-07, 21:55 GMT
Posts: 756
Location: N 42.38846 W 83.45456
I have been taking things a bit slow , waiting on feedback


Top
 Profile  
 
 Post subject: Re: Questions and help
PostPosted: Sat, 14-09-13, 20:16 GMT 
Offline
Site Admin
User avatar

Joined: Fri, 31-08-07, 7:01 GMT
Posts: 4465
Location: Hamburg, Germany
John,

are there some crucial checks users can do with some of the Spice kernel files, to test critically that everything went fine? It would be great if some of us were interested enough in testing various Spice files carefully, such that we can really have confidence in them.

Fridger


Top
 Profile  
 
 Post subject: Re: Questions and help
PostPosted: Sat, 14-09-13, 21:58 GMT 
Offline
User avatar

Joined: Tue, 04-09-07, 21:55 GMT
Posts: 756
Location: N 42.38846 W 83.45456
other than having the wrong leap sec. file
i have not had any issues with any of the kernels for the planets or major moons
nor any of the minor moons ( some of these do have limited data )

the only issues i have had have been with spacecraft time coverage
and these do change all the time
Cassini has a lot of overlaps to cover missing time , mainly on predictive kernels


Top
 Profile  
 
 Post subject: Re: Questions and help
PostPosted: Sat, 14-09-13, 22:55 GMT 
Offline
User avatar

Joined: Mon, 03-09-07, 23:01 GMT
Posts: 385
Location: Tuscany, Tyrrhenian Sea
Hi! Feedbacks from a follower of SPICE kernel files.
So far I've been able to load SPICE for Mercury and Venus like described in the forum by John. In my opinion all seem fine because in developing the ephemerides plugin I should see whether something would go wrong amongst VSOP and SPICE; since for whatever error within the plugin, it should be an error for both and not right for one side and wrong for the other; thus far what it is an error for VSOP it is an error also for SPICE and viceversa for what concern the non-errors. :o Indeed I found two questions to be clear, at least just to test the SPICE itself:

1) the "centering" on Solar System Baricenter;
2) the difference amongst the "Modify" and "Replace" directives;

1) the J2000 OrbitFrame centered on SSB doesn't work, and Celestia does crash, as long as it is set with the "second name"; that is: "SSB"; while is working with the first name of "Solar System Barycenter". This is could be a Celestia issue, but more important, such kind of orbit frame doesn't match with whatever planetary ephemerides type with which to test the SPICE itself. The table setting of JPL HORIZONS relevant to the solar-system barycenter shows nothing when one do select such option; just the ephemerides of the target objects are shown and of course they aren't in the positions where they would be once set the SSB. An object must be set on "Sol" to have the same ephemeris; thus I should like to know where to find a "barycentered" ephemeris to check for;

2) the "Replace" directive on my system does crash Celestia, while the "Modify" absolutely not; thus I wonder whether the difference is mandatory or not;


Top
 Profile  
 
 Post subject: Re: Questions and help
PostPosted: Sun, 15-09-13, 3:08 GMT 
Offline
User avatar

Joined: Tue, 04-09-07, 21:55 GMT
Posts: 756
Location: N 42.38846 W 83.45456
fenerit what Operating system are you using

the Replace is needed because the default solarsys.ssc is using
-- for mercury
" CustomOrbit "vsop87-mercury"

if one was to use the modify
there would be two orbits . almost on top of each other but two orbits

mind you i in the mercury page i used
----
Texture "UseYourMercuryMap.ctx"
----
that is a bit self explanatory
and you did place
"de430.bsp"
"pck00010.tpc"
"naif0010.tls"
in
celestia/extras/data
and the barycenter and mercyry ssc's in
celestia/extras/

( a word of warning , one i might want to post on EVERY PAGE )
i alluded to it with stating that they need to be all one file

one big " SolarSystem-SPICE.ssc "
with the barycenter "1.Barycenters.ssc "

there is a Linux ( and maybe mac OSX also) name reading issue
the c-language read order for a list
there is an odd naming scheme that needs to be used in Linux


Top
 Profile  
 
 Post subject: Re: Questions and help
PostPosted: Sun, 15-09-13, 10:39 GMT 
Offline
User avatar

Joined: Mon, 03-09-07, 23:01 GMT
Posts: 385
Location: Tuscany, Tyrrhenian Sea
John Van Vliet wrote:
fenerit what Operating system are you using

the Replace is needed because the default solarsys.ssc is using
-- for mercury
" CustomOrbit "vsop87-mercury"

if one was to use the modify
there would be two orbits . almost on top of each other but two orbits



In this case my OS is still Windows. What I do not understand is that also Venus is using "CustomOrbit "vsop87-venus" inside the "solarsys.ssc" and in that case the directive you have specify is "Modify". For the rest, concerning the file/folders, I've followed exactly your instructions.


Top
 Profile  
 
 Post subject: Re: Questions and help
PostPosted: Sun, 15-09-13, 23:41 GMT 
Offline
User avatar

Joined: Tue, 04-09-07, 21:55 GMT
Posts: 756
Location: N 42.38846 W 83.45456
the "modify" on venus was a mistake , now fixed

as to crashing ?
just a speculation
is celestia installed in c:\\Program Files
if so the UAC will cause all kinds of problems and celestia will not work correctly


Top
 Profile  
 
 Post subject: Re: Questions and help
PostPosted: Mon, 16-09-13, 7:57 GMT 
Offline
User avatar

Joined: Mon, 03-09-07, 23:01 GMT
Posts: 385
Location: Tuscany, Tyrrhenian Sea
John Van Vliet wrote:
the "modify" on venus was a mistake , now fixed

as to crashing ?
just a speculation
is celestia installed in c:\\Program Files
if so the UAC will cause all kinds of problems and celestia will not work correctly


Nothing about all that, John; just my stupid fault with the "albedo" string inserted in the wrong place.

1) Also the SSB now works like would be, thus I do not know why planets was displaced; maybe for the "Modify" issue?
2) Mercury is good in all;
3) Venus is good in equ./ecliptic/Az./alt. coordinated while it is too much inclined; the sub-solar point is at 24 degrees while should be at about 2.4 degrees; also the Central Meridian is not where should be; thus it seem more matter of SpiceRotation than SpiceOrbit.


Top
 Profile  
 
 Post subject: Re: Questions and help
PostPosted: Mon, 16-09-13, 8:24 GMT 
Offline
User avatar

Joined: Tue, 04-09-07, 21:55 GMT
Posts: 756
Location: N 42.38846 W 83.45456
this is what i get from using back up files to recreate the ssc after editing the alignment of the code to clean it up
added back in fixed errors

venus spice should be this
Code:
 # SPICE
     {
       OrbitFrame { EclipticJ2000 { Center "Sol/Venus_bary" }}
       BodyFrame  { EclipticJ2000 { Center "Sol"            }}     
       Ending     "2649 11 25 00:00:00.000"  # less 3 month for orbit

"EclipticJ2000" for both of the frames
now fixed :mrgreen: Image


Top
 Profile  
 
 Post subject: Re: Questions and help
PostPosted: Mon, 16-09-13, 13:13 GMT 
Offline
User avatar

Joined: Mon, 03-09-07, 23:01 GMT
Posts: 385
Location: Tuscany, Tyrrhenian Sea
Never mind. Solved.


Top
 Profile  
 
 Post subject: Re: Questions and help
PostPosted: Mon, 16-09-13, 18:53 GMT 
Offline
User avatar

Joined: Thu, 11-11-10, 19:36 GMT
Posts: 20
Having installed earlier your Mercury2Neptune-spice add-on, I'm closely following and implementing this thread to modify that installation regarding your new insights/updates. Thanks for the efforts and looking forward towards Pluto ;)

Marco


Top
 Profile  
 
 Post subject: Re: Questions and help
PostPosted: Mon, 16-09-13, 20:00 GMT 
Offline
User avatar

Joined: Tue, 04-09-07, 21:55 GMT
Posts: 756
Location: N 42.38846 W 83.45456
the inner solar system is rather easy to update
Earth has 1 moon
Mars has 2

the Moons are the fun part , they take a lot of time

Also i have been posting things a bit slow . that way there can be feed back

and to allow time to finish updating the moons of Uranus, and Neptune


Top
 Profile  
 
 Post subject: Re: Questions and help
PostPosted: Tue, 17-09-13, 19:06 GMT 
Offline
User avatar

Joined: Thu, 11-11-10, 19:36 GMT
Posts: 20
John

Just a remark to be certain....
As you explained in the The Barycenter.ssc:

John Van Vliet wrote:
two odd ones are
----
Visible true
Clickable true
----
this is overiding the celestia default orbits SO
if you want to see the orbit and be able to click on the body for this orbit ,these need to be set to "true"


In your previous Mercury2Neptune Spice addon, you also used these parameters in the planet ssc's.
Now in your 4 examples for Mercury to Mars, I do not see them in those files anymore. Correct?

Marco


Top
 Profile  
 
 Post subject: Re: Questions and help
PostPosted: Thu, 19-09-13, 7:34 GMT 
Offline
User avatar

Joined: Tue, 04-09-07, 21:55 GMT
Posts: 756
Location: N 42.38846 W 83.45456
with it set in the barycenter ssc it is not needed in the solarsystem ssc

wrapping my brain around using the spice kernels and having orbits line up has been a long learning process

And one of the goals of this is to help find any mistakes and fix them

and if someone has a DIFFERENT way of doing this
and compare it

using the barycenter is not the only way for the planets
the moons , it might be better but the planet center could be used
spacecraft ? maybe with the center instead of the barycenter


Top
 Profile  
 
 Post subject: Re: Questions and help
PostPosted: Thu, 19-09-13, 12:30 GMT 
Offline
User avatar

Joined: Mon, 03-09-07, 23:01 GMT
Posts: 385
Location: Tuscany, Tyrrhenian Sea
A question maybe not directly concened for SPICE. Probably it has been already found. The Moon's apogee can't be morer than 408k km within the range of millennia. With "iau-moon" it could be up to 420k. With SPICE too, it achieve the same exaggerated distance. What is the issue here?


Top
 Profile  
 
Display posts from previous:  Sort by  
Post new topic Reply to topic  [ 30 posts ]  Go to page 1, 2  Next

All times are UTC


Who is online

Users browsing this forum: No registered users and 1 guest


You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot post attachments in this forum

Search for:
Jump to:  
cron
Powered by phpBB® Forum Software © phpBB Group