Some old cel's don't work

Have a question about using Celestia? Check here first for FAQs and helpful advice.
Forum rules
Please help to make this forum more useful by checking the FAQs before posting! Keep it clean, keep it civil, keep it truthful, stay on topic, be responsible, share your knowledge.
Topic author
Hoover
Posts: 55
Joined: 16.06.2004
With us: 15 years 3 months

Some old cel's don't work

Post #1by Hoover » 25.01.2011, 20:38

Hi,

A long while back there was a favorite views thread such that contained (for example) "9 BC Mars Transits Saturn" which I originally posted in 2004. After a long hiatus I've reinstalled Celestia to find that it no longer shows the right view. However, it appears that this cel was fixed by someone (thank you!). The difference between the two cel's is below, the top being the old and the bottom being the new.

Is there an easy way to fix the old cel's? I have some cel's that I have not found updates for in the forum and would like to convert them.

What was the nature of the change?

Roger

cel://SyncOrbit/Sol:Earth/-009-01-30T15 ... 71559&lm=0

cel://SyncOrbit/Sol:Earth/-009-01-30T15 ... lm=0&ver=2

Avatar
jogad
Posts: 458
Joined: 17.09.2008
With us: 11 years
Location: Paris France

Re: Some old cel's don't work

Post #2by jogad » 25.01.2011, 22:18

Hello,

Hoover wrote:Is there an easy way to fix the old cel's?
Sorry no! :(

Moreover, the 2 kinds of urls are for Celestia version 1.4 and celestial version 1.5. and this latter may work or not with celestia 1.6 !

Hoover wrote:What was the nature of the change?
Several changes make the conversion difficult. The most important is that the center of the universe has move to about 206 UA from its original position.
And now the center of the sun has not a fixed position like before but is moving around the barycenter of the solar system.
Add another constant for the conversion from km to ly and a different value for the inclination of the Earth and you'll have an idea of the problem.

My advice is to launch 2 versions (1.4 and 1.6) of celestia. Yes it is possible!
Launch your old cel:url with celestia 1.4 and try to have the same position in celestia 1.6. then save the new cel:url
If you have a lot of cel:urls to convert this may take a while :(

Avatar
selden
Developer
Posts: 10069
Joined: 04.09.2002
With us: 17 years 1 month
Location: NY, USA

Re: Some old cel's don't work

Post #3by selden » 26.01.2011, 13:40

Another problem is with URLs near the surface of the Earth. The Earth's rotation in v1.6 is a function instead of a constant. It's much more accurate but it causes old url definitions to be at different positions relative to the Earth's surface.

I had to provide an SSC which Modifys this change in order for many of the URLs in my Hale Telescope Addon to continue to work. Redoing them all would have been a long, tedious job.
Selden

Topic author
Hoover
Posts: 55
Joined: 16.06.2004
With us: 15 years 3 months

Re: Some old cel's don't work

Post #4by Hoover » 26.01.2011, 23:39

Hi,

Thanks for the info. A long time back I had posted some interesting transits and occultations. Data for some planetary interactions can be found at

http://www.projectpluto.com/mut_pln.htm
http://en.wikipedia.org/wiki/Astronomical_transit
http://en.wikipedia.org/wiki/Occultations

Some of the ones I had were fixed at ver=2 in the forum. But it was better that I could remember how I did these to begin with. Once a planet was set up for one event, all I had to do was change the date and get to the next event and so on.

So there wasn't a whole lot of work involved. It would be possible, once one link was created

I am thinking about making a web page(s) with cel urls for all of these events. However, I am concerned that the format may change again. These links would work for version 1.6 going forward up until a version occurred where the wouldn't work anymore.

Roger


Return to “Help Central”

Who is online

Users browsing this forum: 8 guests