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Questions tagged [the-moon]

Questions regarding Earth's only natural satellite.

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How to calculate exact angle to the moon?

I am building some device as a gift for my girlfriend. For this device to work, I need to be able to calculate the angle to which I should look towards (3D angle), in order to see the moon. This ...
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2answers
152 views

Why does the half moon appear to have a “nose”?

Yesterday evening, the moon from my place looked like this: Basically, instead of the crescent shape I am used to it looked like there was three tips: one at each extremity (as usual) and one in the ...
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1answer
43 views

Celestron Astromaster EQ130

I recently purchased a Celestron Astromaster EQ130 telescope and have absolutely no clue about telescopes but would love to learn. I have set this up but cannot even get a decent view of the moon, any ...
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1answer
108 views

What percentage of the celestial sphere can the Moon cover?

I was solving a task that said (paraphrasing): What percentage of the night sky can the Moon cover during the entire year, when observed from all points on Earth (what percentage of the night ...
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1answer
230 views

What phenomenon causes “lunar waves”?

In multiple video clips of the moon but also one of Jupiter, some kind of waves can be observed. Is this just the effect of the object moving behind layers of different refractive indexes (similar to ...
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1answer
62 views

What irradiance does the Moon receive during a total lunar eclipse?

As we know, the total solar irradiance normally received by the Moon is about 1361 $W/m^2$ (the same as the top of the Earth's atmosphere). Of course, this changes during lunar eclipses, but the Moon ...
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2answers
86 views

Direction of major axis of moon's orbit

Does the major axis of the moon's orbit point in the same direction (with small deviations) throughout the year? or does it migrate along a path so that after a million years it might be 90° away from ...
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2answers
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Can the Moon eclipse Venus?

The title basically says it all. As seen from the Earth, is it possible for the Moon to eclipse Venus (or any other planet) or are the orbits inclined such that this never happens? If such an eclipse ...
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1answer
101 views

How would a flat mirror on the Moon reflect sunlight

I was solving a task that said (paraphrasing): There is a flat mirror on the Moon, whose reflection coefficient is 100%, and observers on the Earth observe it as a star whose apparent magnitude is $...
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1answer
81 views

How big does the moon have to be to have the Earth tidally locked to it

I would like a earth-moon system like Pluto-Charon (but with earth instead of Pluto) where both will be tidally locked to each other within something like a billion years. As the moon would probably ...
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1answer
139 views

Lunar orbit distance

Can anyone calculate the distance the moon travels in a single year? I can calculate it as it is close to 2.4 million km, but I need adjustments as the earth is moving and so is the Sun. So, I need ...
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1answer
72 views

“Lunar tropics”

The tropics is region of the Earth in which the Sun could be directly overhead. What is the corresponding region for the Moon? Is it the same or slightly larger? I live in the UK and hence have ...
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1answer
69 views

What bright body is next to the Moon in these photos of the ISS transiting the lunar disk?

The question What are the chances that the ISS transits the moon as seen from your house (or headquarters)? links to the SpaceX Instagram-posted photos of the ISS transiting the Moon's disk as seen ...
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1answer
87 views

Computing orbit positions of Jovian Satellites / Moons using JPL data

I've been trying to build a model of the solar system in a game. Thus far I've succeeded in placing each of the planets in position using Keplerian elements and formulae from https://ssd.jpl.nasa.gov/...
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1answer
95 views

Can a solar eclipse be directly overhead?

I have trouble picturing eclipses and whether the moon can be directly overhead.
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1answer
34 views

Recognising lunar month only by looking the sky

Suppose somebody went on an island and don't have sense about time, dates, months. The only thing he has is seeing the sky. Is it possible to recognise which lunar month it is by just looking the sky? ...
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1answer
90 views

Why was the July 27th 2018 lunar eclipse not visible in North America?

I was just wondering if it had anything to do with the fact that last year we were blessed with the opportunity to see the total solar eclipse in our neck of the woods. So this is the universe's way ...
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1answer
107 views

Different full moon face on different places on Earth same time

I have theoretical question. Let's assume that it is full moon and two different humans are looking at it at the same time. One human is for example in London and one in Beijing. It doesn't really ...
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0answers
205 views

What is the highest resolution image of the moon taken from Earth's surface?

According to this article: https://www.theguardian.com/science/2018/jul/26/star-spotted-speeding-near-milky-way-black-hole-for-first-time the Very Large Telescope is "powerful enough to see a tennis ...
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1answer
208 views

Moonless nights?

My husband has told me that there are nights when there is no moon in the sky, because it has risen in the morning and set before dusk. I don’t believe him. Does this happen?
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2answers
55 views

Determine full Moon position into sky from Sun position

Soon a lunar eclipse will take place soon. I'm not sure if I will be able to see the moon during the eclipse (from 9:30 PM to 11:00 PM), because, I have some building, mountains... in my field of ...
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0answers
103 views

Are Saros series separated by “40” in numbering related in any way?

Can anyone help with this question? My question arose from an eclipse related observation that I made while looking into lunar Saros series 129. It is the Saros series number for the lunar eclipse ...
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1answer
43 views

Do celestial bodies actually appear larger along the horizon? [duplicate]

Whether it be the moon (especially when full) or tonight, as Mars is closer than it has been in decades, it appears that these bodies are larger when close to the horizon than overhead. Is this an ...
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1answer
53 views

How come moon's difference in thickness between sides does not create an unbalance on its mass?

I've just found out that moon's dark side is 30 miles thicker then the closer side to the Earth. So I'm wondering about moon's mass. How come it's still balanced? Supposing the far side is indeed ...
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1answer
98 views

Changes of the velocity of the Moon due to impacts from other objects?

Has the moon’s velocity changed since ‘shortly’ after it’s formation due to impacts? Wouldn't it be likely that a significant collision would have occurred over such a long period of time? It ...
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5answers
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Why is moon light not the same color as sunlight?

The light from the moon is light being reflected from the sun. The sun, in space, is white. But on Earth, when the light is filtered through an atmosphere, the light appears yellow. So then, why is ...
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2answers
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Why moon sighted only in Kerala but not in rest of India?

I know for most of you the question may look silly, but Kerala is a state in India where the moon (Ramadan moon) will be sighted but not in rest of India. I was reading the news article where I got a ...
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4answers
330 views

Is it practical to build a giant telescope in Moon? (Considering the fact that the atmosphere of moon is very rare)

China's FAST (Five-hundred-meter Aperture Spherical radio Telescope) is the largest radio telescope in the world.(This is huge!!!) As we all know Space Telescopes are better than Earth-Based ...
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1answer
86 views

Solid-body tides on the Moon

There are various good models for solid-body tides on the Earth. Are there any recommendations for tides on the Moon?
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4answers
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Hypothetically, would we be able to see the moon from Saturn's North Pole?

Hypothetically speaking, if Saturn had a solid surface that we could stand on, would we be able to see our Moon from the North Pole of Saturn? Would the rings of Saturn obstruct the view?
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1answer
107 views

Is there a significant temperature difference on the moon from apogee to perigee or vice-versa?

Do those few thousand kilometers of difference going around the earth significantly affect the amount of thermal energy the moon receives from the sun to warm up its surface? Also, are there more ...
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3answers
106 views

Why is the color of the moon so similar to the clouds?

Why the moon looks like the cloud-structure on the blue sky among the clouds?
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1answer
40 views

Ancient greeks know about leap day? [closed]

I'm reading about Antikythera machine and its functions. So I read about solar cycle and moon cycle and how they used 19 solar years to compare with 235 lunar cycles. So this is my question: They ...
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1answer
203 views

How much do starlight and artificial light illuminate the Moon?

The Moon receives most of its light from the Sun, either directly through sunlight or indirectly through Earthshine. However, there are many other dimmer sources of illumination. Starlight. This is ...
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3answers
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Is the moon's revolution speed increasing or decreasing

I've come across multiple answers to this question. So, the moon is moving away from the Earth a couple of centimeters per year and the Earth's rotation is slowing down. Here it says the moon's ...
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0answers
79 views

How fast was the Earth spinning directly after the Moon formed?

I understand the Moon was perhaps five Earth radii away when it first formed (assuming it was formed by a giant impact of a Mars-sized body), and Earth has since transferred its rotational energy into ...
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1answer
145 views

Implementation of formulae for Meeus for the Moon

With Astronomical Algorithms by J. Meeus (1998) I have obtained the relevant illuminated fraction of the disk and position angle. But they're numbers (all Greek to me!) I know, Meeus explains that ...
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1answer
134 views

Place on Moon that always lit?

Is there a place on Moon (sure it's near north or south pole) that is always lit by sun? It's to install solar panels if I will choose to make rancho there :) What diameter of Moon Polar circle? How ...
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1answer
92 views

Axial wobble or binary star system

Is our solar system affected by a body unobserved as of yet that causes our solar system to curve through space in an orbit? Is this idea outlandish or us there any evidence to support it? Consider ...
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1answer
132 views

How to calculate the position to be to see ISS passing in front of the moon or the sun?

I would like to know how to calculate the time/date of the ISS passing in front of the moon (between the observer and the moon) or the sun, or to calculate the position in which the observer have to ...
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2answers
149 views

How can Earth-Sun Lagrange points L1 & L2 even be semi stable considering the moon?

I know that the Earth-Sun Lagrange L1, L2, and L3 points are not considered stable over longer periods, especially when compared to L4 and L5... But, with the moon orbiting the Earth in the general ...
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1answer
294 views

Moon inclination

The Moon is inclined to the ecliptic 5.15 degrees, and the equator of the Earth tilts 23.44 degrees. Since the Moon's ascending node to the ecliptic rotates, the Moon's inclination to the Earth's ...
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1answer
2k views

What is the distance of the Earth's orbit around the Moon?

I realize the Earth and the Moon both orbit around their shared center of mass, and that in the case of the Earth and Moon this center is "inside" the Earth. However, I'm looking for an approach to ...
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2answers
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Are red moons possible without eclipses or smoke from fires?

This morning I was on the bus and as I looked out of the window I saw that the moon was larger than usual and red. I live in eastern Norway and it was about -20ºF / 30ºC outside. There's no forest ...
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1answer
228 views

Why are tides high only on a full moon day?

As far as I've known, sea tides are higher on a Full moon day. And that is due to the "gravitational pull" of the moon. But we know that moon is visible because of reflection of sun's rays. So, even ...
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1answer
61 views

When will the next 'Super Blue Blood Moon' occur?

I missed the sight yesterday (1 feb 2018) because I live right in the region where the sight was not visible. So when will the next Super Blue Blood Moon occur?
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2k views

How does the Moon look like from different latitudes of the Earth?

I have heard, that on the northern hemisphere, you can estimate a direction of south if you imagine a line going through the tips of the border between illuminated and shadowed part of the Moon, and ...
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3answers
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Why is the Earth-Moon distance not the same at each perigee/apogee?

I wonder why the Earth-Moon distance is not the same at each perigee/apogee. Isn't the Moon's orbit a fixed ellipse with Earth at one of the foci? If it is so, shouldn't the distance at perigee/apogee ...
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1answer
243 views

How large could a second moon of Earth be?

Question in the title. Let's say that I have a lot of garbage- mined-out asteroids, spent nuclear fuel, satellite debris, and just general trash. Also safe ways to get these into Earth orbit. Instead ...
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What does Ptolemy mean by “a line drawn from the centre of the earth through the centre of the moon to a point on the ecliptic”

This is from a translation of Ptolemy's Almagest Hence it necessarily follows that the straight line draw n from the centre of the earth (which is the centre of the ecliptic) through the centre of ...