# Tag Info

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### How does the sun move over the year in the sky of the Moon?

That's right. Unlike the Earth, which has a substantial inclination of 23.4 degrees to the ecliptic, the Moon is inclined by only 1.5 degrees. This means that there are no substantial seasons. The ...
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### Why aren't there eclipses every month when the moon's orbit is aligned with the ecliptic as a result of lunar precession?

There are few things here I think might be worth to state: The tilt of Earth is of no importance here. As the comment says what is of importance how much the Moon orbit is inclined to the ecliptic. ...
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### Why aren't there eclipses every month when the moon's orbit is aligned with the ecliptic as a result of lunar precession?

The precession of the moon's orbital plane does not align it with the ecliptic plane. The angle between those two planes is approximately 5.14° (it varies by ~±0.15°, mostly due to perturbation by the ...
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### Inclination of planets

While the other answer here and the link provided by Jeremy give excellent explanations, I believe a bit more nuanced reasoning is required. Although the theory of planet formation is currently still ...
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### How does one calculate inclination from a graph of radial velocity?

From its RV graph alone, with no other information, you cannot calculate inclination. This is why RV velocity measurements are typically reported as "$v \sin{i}$", because what you're actually ...
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### Inclination in Kepler's laws

I am assuming that the question you want answered is how to calculate the elevation of an orbit above a reference plane given the orbital inclination with this plane. If so, please update your ...
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### How can a planet have a 90° inclination?

As Wikipedia notes, Since the word 'inclination' is used in exoplanet studies for this line-of-sight inclination then the angle between the planet's orbit and the star's rotation must use a ...
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### Eccentricity and Inclination of a Star

Sirius is a binary system, composed of a main sequence star (Sirius A) and a white dwarf (Sirius B). The two orbit each other with a period of about 50 years, and the eccentricity given on Wikipedia ...
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### Why do Uranus' and Pluto's moons orbit the equator? What makes a moons' inclination tilt with the rotational axis of their planet?

I have managed to find two hypotheses for Uranus's tilt that explain why its moons are also orbiting on a tilted plane. The multiple impacts hypotheses lies on the fact that, if Uranus had become ...
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### Inclination of planets

To answer your second question: Upsilon Andromedae c and d have mutual inclination of 30 degrees http://en.wikipedia.org/wiki/Upsilon_Andromedae Note that you cannot calculate mutual inclination by ...
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### Inclination in Kepler's laws

So, basically you're trying to merge orbital inclination to Kepler's laws. The simplest way is to take the measured orbital inclination of the planet, which is constant, and apply the Pythagorean ...
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### What is the difference between inclination and obliquity?

The inclination is the angle between the plane of the orbit and some other standard reference plane. For orbits around the sun, the reference plane is usually chosen to be the ecliptic, that is the ...
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### How does one calculate inclination from a graph of radial velocity?

@NeutronStar's excellent answer sums up the situation nicely: From its RV (radial velocity) graph alone, with no other information, you cannot calculate inclination. This is why RV velocity ...
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### Why do Uranus' and Pluto's moons orbit the equator? What makes a moons' inclination tilt with the rotational axis of their planet?

Just as tidal forces can push a moon outwards and over time, circularize the orbit, the planet's equatorial bulge has a similar force that draws the Moon into an orbit over the equator. This is true ...
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### How to estimate the inclination of a galaxy between edge on and face on?

If you tilt a circular object, then along one axis the length will appear to be shortened, while along a perpendicular axis the apparent size will be unchanged. So you can use that to determine the ...
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### What is the magnitude of variation of Earth's orbital inclination?

In a solar system model by Varadi Runnegar and Ghil Earth's inclination varies between 0 and about 0.05 radians (or about 3 degrees) The variation is rather chaotic, but you may note that there seems ...
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### why does pluto have a high orbital inclination

I think the best answer is that there is no particular reason. In any planetary system, most orbits tend to stay close to a common plane - close, but not exactly there. Even the big planets are ...
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### Inclination of planets

It starts with the formation of the solar system. The solar system started off in a large cloud of gas, under gravity, this cloud started to collapse. Most of the mass was concentrated at the centre ...
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### Precise declination of Moon

I just want 28.88 deg = 28 deg 53' confirmed. Yes, 0.88 degrees is equal to 53 arc minutes, so 28.88 deg = 28 deg 53'. But the Yahoo source is off in its value. According to this reference, the ...
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### Can we learn anything from observing galaxies edge-on, like the Spindle Galaxy?

Yes, we can certainly learn things from edge-on galaxies. The easiest things to learn, as you suggest, have to to with the vertical structure of the stars (and gas). For example, our knowledge of how ...
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### Moon inclination

Our moon is special. Other planets have relatively much smaller moons. The other rocky planets either have very small moons (Phobos and Deimos are probably captured asteroids) or no moons at all. ...
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### Is Earth the most inclined or not?

The confusing thing is that inclination is not the only thing defining an orbital plane; it also matters where the ascending node is. Only if all ascending nodes would be in the same direction, you ...
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### Guess inclination angle from radial velocity measurements

It is possible that you have not understood the definition of inclination angle. This is the angle between our line of sight and the orbital axis of the star-exoplanet pair. Maximum amplitude radial ...
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### Guess inclination angle from radial velocity measurements

Radial velocity is a measurement in the change of speed of the star towards us, due to the planet's rotation around it. Speed variation change is detected thanks to the Doppler spectroscopy. If the ...
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### Determining inclination angle of interacting binaries

I think you are referring to the orbits of visual binaries, since you are asking about parameters measured from an ellipse. If the orbital plane were at right angles to the line of sight, then the ...
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1 vote

### Planetary Declination and Axial Tilt

A planet's apparent position in the sky is determined by orbital geometry alone. The tilt of its axis only affects its orientation as we see it in a telescope. It's easier to think of the solar ...
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1 vote

### How can we learn the inclination of the orbiting plane of the exoplanets using radial speed method?

I assume you are talking about the radial velocity method. Analysis of a radial velocity curve yields the minimum mass of a planet $M \sin i$, where $M$ is the true planetary mass and $i$ is its ...
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1 vote

### Reasons for orbital inclinations

The planets formed from a disc of dust and gas. Since the orbiting the proto-sun formed into a disc the planets, which formed from this matter are in a disc too, but not a perfect disc. There was some ...
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