Questions tagged [moon-phases]
For questions about the various phases on the Moon as observed from the Earth, also known as waxing and waning.
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Is this "lunar theorem" known?
About a month ago I concieved the following "lunar theorem":
Whenever the moon is visible at dusk (strictly speaking, to an equatorial observer, if eg. the planet is very large compared to ...
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What does the moon's phases look like from the Equator?
I recently found out that the moon's appearance changes based on one's latitude, and while googling for more information I found conflicting images about what the moon's phases look like from the ...
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How close is a typical New Moon to the Sun in the sky?
In a Solar Eclipse, the Sun, Earth and Moon are exactly colinear (well some area of the Earth where the eclipse is visible), and these are relatively rare.
But in addition, Sun, Earth and Moon are ...
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What phases of a moon orbiting Proxima Centauri b could be seen?
Assuming a moon like Earth's natural satellite would be orbiting the Proxima Centauri b at a similar distance, what moon phases could be seen from the planet's surface at coordinates 0;55?
Adding ...
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The shape of the moon limb/crescent (terminator line)
Given that that n% of the moon is illuminated. I want to (approximately, but more or less correctly) draw the the terminator line on the circle (that represents the ...
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Calculate moon illumination given moon age
trying to compute moon illumination percent from moon day.
To get moon day in pseudo code I do:
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How long before two sidereal months start on the same lunar phase?
I was reading about the difference between the sidereal and synodic month when I started to wonder how many sidereal months need to pass before you get two that start on the same part of the synodic ...
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Metonic cycle observation & display [closed]
I'm unable to locate physical display observatories for the 19 year Metonic cycle. How do I display this information & calendar detail on a concrete floor near the tropic of cancer?
I seek a floor ...
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What kind of effects would two moons have on an earthlike planet?
On Earth our moon has several effects: it generates two high and two low tides a day; it slows down the spin of the planet and stabilizes its wobble, etc.
So, what possible effects could two moons, ...
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New moon rise same spot on horizon as sunrise, almost same time [closed]
I witnessed the new moon rise just ahead of a sunrise at the very same spot on the horizon. How often could I plan on looking for that occurrence again?
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Trying to understand lunar phases
Complete novice here. I'm trying to understand what appears to be two approaches to quantifying lunar phases. Have I got this right?
Named lunar phases can be understood as the Moon's ecliptic ...
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JPL Ephemeris or Skyfield - how to get moon phase percentage (not illumination percentage)
I know how to use JPL's Horizons to get moon illumination percentage but I noticed that even at new moon, the illumination never goes to zero:
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Why doesn't lunar perigee always occur in the same lunar phase?
If the phases of the moon and the moon's perigee are just dependent on the point that the moon is in through it's orbit, why can perigee happen at different phases of the moon?
My thinking is this:
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tool to calculate moonrise/moonset and moon phase for any date for any location
I have googled for such a solution but I have not found anything substantial: I found one website but it was someone's side hobby so my confidence in it is low.
Thankfully, I have discovered ...
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How often does a full moon happen on the weekend?
Wikipedia says that a synodic month has a length 29 d 12 h 44 min and 2.9 s.
I'm interested to find out how often a full moon (but actually, it's the same for any phase) happens during a weekend.
I ...
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Is there a word or short phrase that denotes the apparently moving part of the lunar limb?
Between new moon and full moon, the moon's disc as viewed from the earth is bounded by a semicircular arc on its right and an arc on its left that moves to the right until at full moon it forms the ...
user31481
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what percent of moon must be illuminated to be visible with naked eye and clear sky?
Originally, the new Jewish month was determined by the sighting of the new crescent moon.
There are online calendars that give percentage of moon that is illuminated.
Using the computations from these ...
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How is this picture of the moon possible?
I need help understanding this images I personally took. If the phases of the moon are determined by the position of the earth, moon & sun. Then how is the moon a crescent while it is rising in ...
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looking for a plugin or API for Moon-phases and sky-map
I want to create a website that contains star maps and moon phases like mapiful and thatverynight but couldn't find any helpful APIs or plugins.
Can anyone help?
thanks
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When can Moon occult Venus?
I'm trying to solve this task:
At what age of the Moon (in days after the new moon) is it possible for the Moon to occult Venus?
How I was solving it:
Angular velocity of the Moon is 13.2 degrees ...
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What percentage of the time can we see the moon during the day?
From sun rise to sun set what percentage of the time is the moon visible?
I saw one thing at the top of google saying an average of 6 hours a day but that seems like a weird way to answer it. Would ...
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Is there software that will let me calculate things like lunar phases and the position of bodies in the sky in a custom solar system?
I am constructing a fictional solar system and want to be able to calculate astronomical events and locations, like lunar phases and eclipses, plus the positions of other astronomical bodies in the ...
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How to determine how often a planet's center will be collinear with its moon's?
Expanding on the question: Let's say I have a planet orbiting some star (earth-like, sun-like, for the sake of example). If this planet has two moons, M1 with orbital period of 30 earth-days and M2 ...
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Would people on opposite sides of the earth see different details of the moon, if so are there actual photos demonstrating this?
I am aware of phases and the fact that opposite sides will see the moon flipped relative to the other but what I’m asking specifically is would the almost 8000 mile difference between the two ...
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What are the aspects does the moon differs between cities located on the same latitude?
What are the aspects does the moon (astronomical position and other astronomical aspects) differs between cities located in the same latitude? - For example: Seattle, Munich, Vienna, and Ulaanbaator ...
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Apparent Magnitude of First quarter Moon [closed]
Given
Apparent magnitude of moon is -12.5.
Distance of moon and earth is 384400 km.
Diameter of Moon is 31 arcmin.
Phase of moon is 0.5.
Find the apparent magnitude of first quarter moon.
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Is there a precise definition of "Supermoon"?
Elsewhere online I keep reading that a supermoon is the situation when full moon coincides with moon perigee. But see this plot from wikipedia Lunar Distance entry
The perigee distance varies wildly ...
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How to get the percentage of the Moon illuminated as a function of time?
As the title suggests, I need a way to get the percentage of the Moon's disk which is illuminated as a function of time.
There are simple geometrical expressions for the fraction of a sphere ...
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Moon cycles used for gardening & harvesting
I appreciate that this question may deviate from the standard astronomy questions.
I have recently read an article that suggest that gardeners, farmers & winemakers etc sometime use the moon's ...
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Is it easier to see the young moon when it's closer to the sun?
With the naked eye, would it be easier to see the moon when it's close to the sun, because it might reflect some more light (or not, I'm not sure) or farther from the sun because the sun shines ...
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Moon phase angle
When I look at a visible moon in daylight its phase is shown at an angle. However textbook moon phase diagrams only show the phase vertically. What is it that determines the angle?
The reason I ask ...
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Determining the percentage area of the moon's disk shaded with respect to time
I've looked online and I've found sources such as this paper on a lunar phase simulator as well as this article about lunar phases.
I'd like to be able to model the area of the lunar disk which is ...
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How to map moon phase number + "lunation" to moon phase name?
I am querying an API (weatherbit) which returns a moon phase number which looks like this:
0.9594168
For the 16 days I look at the numbers vary from 0.006 to 0.99.
I have 8 "moon phase" ...
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What are "p" and "r" wrt the moon?
Still learning, thinking - and failing - about the moon.
timeanddate.com has this cute and dynamic moon sketch at e.g. https://www.timeanddate.com/moon/uk/london
They generate this based on three ...
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Mapping illumination to moon phase (font) icon
I use algorithms that give me the moon phase, age and illumination (and more) for a given timestamp and location. I am struggling to map that information to a (font) icon of the Moon Phases font. Each ...
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Historical Lunar Tables and the Associated Error Bound
Consider as an example, AstroPixel's ``Six Millennium Catalog of Phases of the Moon''---
http://astropixels.com/ephemeris/phasescat/phasescat.html
My question is two-fold:
How are these tables which ...
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Ladakh India where the moon (Ramadan moon) is sighted but not in rest of India [duplicate]
Today 22 May 2020 around 3 p.m Ladakh India sighted new moon(Ramadan moon) but not in rest of India.I read many articles acc. To them it is not visible today, then how it was seen from Ladakh... .
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Where is the Moon?
I live in Western Australia and I have not seen the moon for almost a solid week. Last I saw it it was almost full, and the sky has been clearer than ever with all the stars bright and visible yet the ...
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How to calculate moon overhead and underfoot time?
For hunting purposes, some hunters follow the moon phases to hunt accordingly. To give some context, here's some links:
Lunar cycle's effects on hunting: https://www.acurite.com/blog/weather-stations-...
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Is it possible to explain the difference between synodic month and sidereal month by degrees?
Is it possible to explain the difference between synodic and sidereal month by degrees - in the following way?
Just recently I learnt about these two types of months, and I want to see if I can ...
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Simple question about the phases of the Moon
If on March 20 the Moon were located at the position of the sun, how can I determine the phase in September 22, June 22, and December 20?
I drew the orbit and calculated by dividing sidereal days to ...
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Calculating the position angle of the moon (the rolling back and forth)
I have been watching the the NASA Moon Phases Video of the year 2020. Pretty much everything makes sense and I know how to calculate it including the moon phases, declination, azimuth, apogee and ...
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How do I calculate moon phase orientation at any Coordinates given all the necessary data?
I'm having a problem for a couple of days where I'm trying to accurately calculate the phase angle of the moon at any given Coordinates (lon,lat).If I know my current Coordinates, Moon and sun ...
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Jean Meeus - calculating moon rise, transit and set times - help isolating error in logic
I've been working my way through the Jean Meeus Astronomical Algorithms book for a few weeks, to implement some of the key algorithms for a personal project. This task has been a little more complex ...
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How to calculate the moon phase angle?
I need to calculate the exact moon phase angle for each our of a day. I have my position in lat and long and a unix timestamp. At the end i would like to be able to caluculate the moon brightness with ...
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How many Moon's Topocentric Conjunction occurs per lunar month?
It is clear that only one Moon's Geocentric Conjunction occurs per lunar month, what about the Topocentric Conjunction for a given location?
without scale I can imagine many Topocentric Conjunctions ...
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Get a table of Moon phase angle per day
Where can I get a table with the Moon phase angle for each day ?
It's available here for a given day, but I would have to input each day of a year to get a full table.
=== NEW EDIT : 2019-09-18 ===...
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Did NASA/JPL get "waning" and "waxing" backwards in this video?
The NASA JPL video What's Up: September 2019 Skywatching Tips from NASA says (per both the closed captions and audio):
We’re in a several-month period right now when the new Moon falls right around ...
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Relation between phase and magnitude
Given the phase of a planet or satellite, I can find the area illuminated visible to us, if we consider a 2D surface. But how do I find the percentage of illuminated area visible considering it a 3D ...
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Struggling to understand the phases of the moon
Source
Typically this diagram is how the phases of the moon are explained but the issue is this, namely, the phases seen on the right half are not possible. All the phases should appear on the left ...
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