Need some help with orbital plane terms, mainly about the Moon.

[mental4astro (Alexander)]

Hi all,

I need some help with terms and to refresh myself on terms I've forgotten to do with orbital plane details. Mainly here with the Moon as it was the subject of my Sunday night viewing.

Ok, the Moon's orbit around the Earth is in a plane. But it is not a tight, flat plane. There is an angular range to this plane, like the ecliptic. Is it called the 'lunar ecliptic'?

What would the two extreme points of this range be called?

Is this 'lunar ecliptic' stable, or does it somewhat wobble? That is, the Moon has periods of a tight, narrow ecliptic range and then wonders off to a broad one? If so, what is this period called?

Is there a good site you can recommend me to read up on this?

I hope what I'm asking makes sense...

Thanks for taking the time to read this.

Cheers,

Alex.

[mental4astro (Alexander)]

Not to worry. I found what I was after.

https://en.wikipedia.org/wiki/Orbit_of_the_Moon

Thanks for looking all the same.

Alex.

[Kunama]

I wasn't aware that there were fluctuations to the angular tilt of the moon's orbital plane. The lunar orbital plane is tilted 5.145degrees from the ecliptic but I understood that this is a stable tilt.

What is the ecliptic? .... If you were standing deep inside the Earth at its very centre and pointed a laser pointed through the very centre of the Sun and that laser beam then extended through the Sun to the sky beyond, then the line that the laser paints in the sky as the Earth revolves around the Sun is the line of the ecliptic. The lunar orbital plane is at an angle of 5.145 degrees to that imaginary line and due to this difference the lunar orbit dips below the ecliptic for half a lunation.

[N1 (Mirko)]

Originally Posted by Kunama

The lunar orbital plane is at an angle of 5.145 degrees to that imaginary line and due to this difference the lunar orbit dips below the ecliptic for half the year.

Hi Matt, did you mean "approximately half a lunation"?
Added up, you do end up with half a year though...or thereabouts.

[Kunama]

Thanks Mirko, I really need to proof read before hitting Enter, fixed. Though if it were so, it would be a long month or a very short year!!
Given that I have the flu, I thought I did well to type anything reasonably sensible at all....

Just found some reading for Alex:

http://www.ruf.rice.edu/~few/Moon%20...0Positions.pdf

[Wavytone]

Alex I have a book you should read that explains all this, remind me to bring it over sometime.

Be ready to take a deep breath.