General Question Time seems offset to UTC

[BerZerK]

Hello, this is my first question here on the forum, because i am really confused.
I thought Orbiter time is UTC and i am quite sure, that the sun used to be at a
realistic position (day/night terminators on the map), when i set the scenario date to "now". But today i found out, that the 00:00:00 midnight is somewhere in central USA. Could it be that an addon changed the time setting somewhere to another timezone?

I made an attachment of a screenshot at the date
21.03.2015 at 00:00:00

In my opinion the day/night terminator should be "midnight" over the UK not in the middle of the U.S.?

 

[kuddel]

Usually your assumptions are correct; 00:00:00 UTC should not produce that kind of terminator location.
Have you maybe installed OMP[1]? I know that this Module does change time-settings in Orbiter, so that "all Players are in sync" (same time).

[1] Orbiter Multiplayer Project

 

[DaveS]

Usually your assumptions are correct; 00:00:00 UTC should not produce that kind of terminator location.
Have you maybe installed OMP[1]? I know that this Module does change time-settings in Orbiter, so that "all Players are in sync" (same time).

[1] Orbiter Multiplayer Project

AFAIK OMP doesn't change the time-settings, it rather inhibits Earth's natural rotation by supplying a modified Earth.cfg.

 

[boogabooga]

Which could still produce what is observed in the figure.

 

[kuddel]

AFAIK OMP doesn't change the time-settings, it rather inhibits Earth's natural rotation by supplying a modified Earth.cfg.

Sorry for spreading wrong informations :blush:

 

[BerZerK]

Have you maybe installed OMP

Yes, i have installed and played OMP a few days ago.

But yesterday i downloaded a bunch of addons from the hangar
and installed them, maybe too much at the same time.
i fear that i overwrote something important, and i dont know what to revert.

I have tried to deactivate all modules, but remains the same.
its always a difference of 6 hours or so.

 

[boogabooga]

Post earth.cfg

 

[DaveS]

Yes, i have installed and played OMP a few days ago.

But yesterday i downloaded a bunch of addons from the hangar
and installed them, maybe too much at the same time.
i fear that i overwrote something important, and i dont know what to revert.

I have tried to deactivate all modules, but remains the same.
its always a difference of 6 hours or so.

As I wrote earlier:

AFAIK OMP doesn't change the time-settings, it rather inhibits Earth's natural rotation by supplying a modified Earth.cfg.

All you need to do is make sure that SidRotPeriod in Earth.cfg (cfg files can be opened with NotePad) reads this: SidRotPeriod = 86164.10132 ;

As I'm not using OMP (never have) I'm not sure if OMP just simply comments out SidRotPeriod with the use of a semi-colon ( in front of it or if it simply is set to 0. In any case, Make sure that SidRotPeriod reads exactly what I specified above.

A second solution would be simply to re-extract Earth.cfg from the base Orbiter package (orbiter100830.zip) and overwrite your old one with the one from the package.

 

[BerZerK]

SidRotPeriod

Thanks a lot for you help DaveS!
I just found it out myself, and wanted to post my solution.
After i crosschecked earth.cfg files with an older version i found a difference in this part:

; === Rotation Elements ===
SidRotPeriod = 86164.09 ; 23h 56m 4.09s (check new reference: 23h 56m 4.0906s)
SidRotOffset = 6.5;4.8956 ; rad(280.5) at J2000.0
Obliquity = 0.4092797095927 ; rad(23.45)
LAN = 0 ; vernal equinox

My Idea was "Sidereal Rotation Offset" could be responsible for this
and i set 6.5 (which i though fit perfectly to the about 6 hours i determined) to 0 and the day/night terminator were fine again!

So thank you all for your help! This drove me crazy this night, finally i can go to bed ;-)

--------

DAMN no it didnt work that way, dont know why it worked a few minutes ago. maybe this is for precession. I better go back to the older earth.cfg

I overwrite it with this:

; === Rotation and precession parameters ===
; ref: see www.orbiter-forum.com/showthread.php?t=8185
PrecessionLAN = 0 ; [rad]
PrecessionObliquity = 0 ; [rad]
PrecessionPeriod = -9413040.4 ; precession period (days) = 25771.5 years
LAN = 0 ; [rad]
LAN_MJD = 51544.5 ; [MJD]
SidRotOffset = 4.88948754 ; [rad]
SidRotPeriod = 86164.10132 ;
Obliquity = 0.4090928023 ; [rad]
;SidRotPeriod (days): 0.99726968
;SidRotPeriod (SI seconds - node to node): 86164.092
;Precession Period (years): -25771.5
;Obliquity (deg): 23.439291
;Ecliptic Obliquity (deg): 23.439291

no it doesnt work
-------------------------------

I dont know whats the difference or why it works better - the old earth.cfg is active - i will see which addons it will affect another day. too tired.

 

[DaveS]

SidRotOffset should be 4.88948754.

 

[BerZerK]

Well thanks, i am no programmer at all,
i just thought several times i have it
but than it turned out even worse.

so i made a cut to end this.................

i renamed current earth.cfg to txt (just to keep it when something goes wrong)
and copied an older earth.cfg into the folder. at least daytime fits again (had problems with my homebase though but i figured out to change a directory name in the cfg file for all the modified bases on the ground).

so many parameters i dont understand thats horrible for me

 

[boogabooga]

You are not the first new Orbinaut to be confused by OMP.

Perhaps OMP needs to come with a disclaimer that 6 months of Orbiter experience is recommended before use. :lol: :hmm:

 

[Face]

You are not the first new Orbinaut to be confused by OMP.

Perhaps OMP needs to come with a disclaimer that 6 months of Orbiter experience is recommended before use. :lol: :hmm:

First: OMP is not modifying the earth.cfg, but the ORRL distribution is.

Before 0.8, the rotation period change was needed to have a better experience in the ORRL setup: Earth-bound races. Unfortunately, without rotation, the Earth in those setups were stuck with WIN in eternal darkness, so we changed the configuration (for the ORRL distribution) to also offset the rotational position for the given epoch in order to bring WIN back into light again.

With 0.8 the need for this hack is gone, so I reverted the rotation period again. However, I've missed the offset, so the current ORRL distro is set with that. It will also be reverted in the next update.

Second: I always tell folks that OMP is beta software. Nevertheless, the ORRL distribution comes with a documentation PDF that states the following in the first paragraph of the installation section:

Extract the archive to a temporary folder, and copy the content of the single directory there (labeled with hashcode and name) into a vanilla Orbiter installation, overwriting files during the process.

Furthermore, Ren's well-maintained server has a clear hint on using this software in a dedicated Orbiter copy: http://omp.ddns.net/en/install.php

Given that the Orbiter community always was (and still is) not very welcoming (not to write "hostile") towards the idea of multiplayer at large, I don't see how putting a large "DANGEROUS" across OMP could do any good. Those who dig enough to find it should be aware that it is not the usual plug&play addon. It is not like I'm running around and advertise it aggressively, now is it?

If you however think that OMP produces too much confusion in the community, because so many newbies struggle with it (like, the two folks in a year or so), I'd like to invite you to contribute to the project to make it more newbie-friendly.

regards,
Face

 

[kuddel]

If you however think that OMP produces too much confusion in the community, because so many newbies struggle with it (like, the two folks in a year or so), I'd like to invite you to contribute to the project to make it more newbie-friendly.

You know that very few will do

But would an entry at the OrbiterWiki FAQ (for example) maybe help those two folks? If that is the right place by the way.

I would write it, if I knew enough about the real reasons.
I would like to avoid writing an answers without knowing exactly what I know (see my post above)
---------------------- Proposal ------
Q: Why is my terminator line not at correct position?
A: Some addons (ORRL versions lower than X.Y.Z) might have overwritten your earth.cfg. To revert to normal operation, re-extract the original Orbiter earth.cfg from the Orbiter basis installation archive, overwriting the current earth.cfg.
Note: Overwriting the "OORL earth.cfg" will void all changes made to that file.
----------------------


/Kuddel

 

[boogabooga]

To a similar point, few new Orbinauts will read the OrbiterWiki, either.

 

[BerZerK]

No big deal!

Common Guys! I didnt want to upset anyone or rub salt in some wounds.
The main problem was, that i dont know the code and its guts like you.
When i play around with addons, i usually do just on thing after another, so that i know what caused problems and what to revert. And when i sat to long in front of the computer, i loose concentration and easy or obvious problems turn into serious issues. And as i am new to the forum, i thought to myself, why not ask the community thats the purpose of that forum.

BTW the OMP Orbiter Multiplayer is something i have searched for very long, so i am very happy that it exists and works.

@Face: Bei mir paßt eh scho wieder ois. Keine Ahnung obs überhaupt am Multiplayer glegn hat, i hob einfach zuviele Addons auf einmal installiert. Inzwischen raucht ma da Kopf scho wieder vo ganz wos anderm ;-) Da gibts beim Orbiter grod gnua, wos me zum Verzweifeln bringd, haha. Aber des is a guads Hirnschmoiztraining und grod deswegen hobe an Orbiter ja ogfangd, weil me de Details a weng mehra intressiern wie der oberflächliche Krampf in "Wissenschaftssendungen" wie Galileo.

 

[Face]

But would an entry at the OrbiterWiki FAQ (for example) maybe help those two folks? If that is the right place by the way.

I don't think that would help much. If newbies don't read the documentation nor the server's own installation page and take care with clearly marked beta software, I don't think they will first look there. Dropping a question here is the more obvious path they'll follow. And as it seems, old-timers know the answer immediately, anyway. No big deal IMHO.

I would write it, if I knew enough about the real reasons.

There is not more than what I wrote in my previous post: it was a hack for the ORRL setup.