General Question having a problrm with orbit

[zeldafan156]

hi, lets say i am trying to place my ship in an orbit that follows the equator line, so its even to both sides of the planet, how do i set that in align planes mfd? also what is LAN im having a bit trouble figuring this out someone please help me with that.

 

[statickid]

just watch the map mfd, and align with the equator like that! if its the ascending (northing traveling) node, then fire orbit antinormal or AN-, if it is the descending node (south traveling) node, then fire orbit normal or DN+

 

[MeDiCS]

LAN: Longitude of Ascending Node. The longitude (how much west or east you are from the reference meridian) in which your orbit intersects the equator when your ship is going from south to north ('ascending' if see north as 'up').

To put your ship in an orbit following the equator, you'll need to have an inclination (Inc) of 0º.

 

[Hasso]

To put your ship in an orbit following the equator, you'll need to have an inclination (Inc) of 0º.

And exactly at this point most of the newbies are stumbling in always the same trap!

You are talking about 0° inclination in an equatorial frame. But only the orbit-MFD may be switched between equatorial and ecliptical frame via FRM-button. Especialy the align-planes-MFD works ecliptical only. You need an ecliptical Inc of 23.45° at asc. node 180° to enter an orbit with 0° against earth's equator.

:tiphat:

 

[Moach]

you don't need align-planes to align to the equador, just set orbit MFD to equatorial frame instead of ecliptical and burn as you pass the equador until Inc reads zero :thumbup:

 

[Hasso]

@Moach

Yes, you are right;

But the align-MFD may help you to burn right in time and to avoid overburns.

Also the OP, zeldafan156, asked for that:

how do i set that in align planes mfd? also what is LAN im having a bit trouble figuring this out someone please help me with that

Last, not least:
If somebody came in here (by forum-search i.e) with intention to make a more precise approach to geostationary orbit?

:tiphat:

---------- Post added 01-07-10 at 16:07 ---------- Previous post was 30-06-10 at 21:14 ----------

I looked a little closer at the values of an earth equatorial orbit in AlignPlaneMFD.

! They are not constant as in ORBITER2006 any longer !

We have to calculate current values matching the date we want to use them.

year Inc LAN
----------------------
2000 23.44 180.00
2001 23.44 179.99
2002 23.44 179.97
2003 23.44 179.96

2005 23.44 179.93

2010 23.44 179.86

2020 23.44 179.72

2050 23.44 179.30

2100 23.44 178.60

2200 23.44 177.21

pretty constant LAN change by 0.014°/year in the period 2000 to 2200

 

[Southwell]

is the LAN change due to lunisloar precession???

 

[Hasso]

is the LAN change due to lunisloar precession???

Exactly that has been my reason to investigate it a little closer.

If the axle of earth is allowed to swing around, the plane of equator couldn't be static to the ecliptic frame any longer.

 

[Southwell]

Exactly that has been my reason to investigate it a little closer.

If the axle of earth is allowed to swing around, the plane of equator couldn't be static to the ecliptic frame any longer.

Have a look at this
[ame="http://en.wikipedia.org/wiki/Precession"]Precession - Wikipedia, the free encyclopedia[/ame]
and scroll about 3/4 of the way down it explains how the ecliptic changes through a period of time, just reminds you how uncertain orbits can be and the pure luck that we are alive today, this is the reason for the ice ages and if human civilization is to exist until the next time we are in that situation it will become the biggest threat to us.

So eventually one day the value for the LAN will return to the value it has today

 

[tblaxland]

is the LAN change due to lunisloar precession???

I'm not sure what lunisolar precession is? The precession you are seeing is due to the precession of the Earth's rotational axis, which is largely unaffected by the Moons orbit. The largest magnitude and longest period effect comes from the Earth's oblate spheroid shape (ie, fat around the middle). Tidal forces from the sun create a torque on the Earth which in turn moves the axis of rotation. The Moon does have a small effect at periods of approx 27.3 days and 18.6 years (not modelled in Orbiter 2010).

Axial precession was implemented as a new feature in Orbiter 2010 (see here for the back story: www.orbiter-forum.com/showthread.php?t=8185). In the specific case of Earth, this phenomenon is also known as precession of the equinoxes.

From the Orbiter 2010 default Earth.cfg:

PrecessionPeriod = -9413040.4  ; precession period (days) = 25771.5 years

 

[Southwell]

Discovery of the precession of the equinoxes is generally attributed to the ancient Greek astronomer Hipparchus (ca. 150 B.C.). The Precession (axial rotation) was later explained by Newtonian physics. Being an oblate spheroid, the Earth has a nonspherical shape, bulging outward at the equator. The gravitational tidal forces of the Moon and Sun apply torque as they attempt to pull the equatorial bulge into the plane of the ecliptic. The portion of the precession due to the combined action of the Sun and the Moon is called lunisolar precession

: Wiki