Welcome to the Equator!! Everywhere on Earth !! USA-UK-Canada

reply to post by CherubBaby


Hi there CherubBaby,

no i am not asking you to time stamp every photo you have posted , it was in relation to the photo you posted at the start of the thread,
and i also said `could you please put a time stamp on any future moon photos`
i just feel it would help

snoopyuk

reply to post by Soylent Green Is People


Hi Soylent. I wanted to ask a straight question. Would you say that a boat moon is normal 12 months out of the year in las vegas ( 35th) parelell? Every month of the year? Yes or no.

reply to post by CherubBaby


Hey Cherub...I thought I would answer your question because no one else has. No...I would have to say that it's not normal. For me, even one month is not normal because Vegas is a long long ways from the equator. Don't be put off by people who just ascribe this to mid-latitude blues. An equatorial moon is a startling sight for us in the mid-latitudes. And month after month of it...more often than not...trippy.

Originally posted by CherubBaby
reply to post by Soylent Green Is People

 

Hi Soylent. I wanted to ask a straight question. Would you say that a boat moon is normal 12 months out of the year in las vegas (35th) parelell? Every month of the year? Yes or no.

Sorry Cherub - I didn't see your question until now.

It depends how at what tilt a person would consider calling it a "boat moon", but basically it will look very tilted for 3 or 4 months around winter, not nearly as tilted for 3 or 4 months around summer, and somewhere in between during the other months around the fall and spring. However, it will always appear at least a little tilted. It can never look completely vertical from Las Vegas. That just doesn't make any sense, if you consider the orbit of the Moon and the fact that people in Las Vegas are basically viewing the Moon while they are standing tilted on the side of the Earth.

To explain why I say the people in Las Vegas (and most of the people in North America) are "standing tilted and sideways" on the Earth, here is a basic graphic below. This graphic is not exact, because it doesn't take into account the normal 23° tilt of the earth. However, for clarity purposes, we can ignore that for now.

This first image is the typical "North UP" view of the Earth and Moon we all have in our heads, and what we always see in books and on TV. Note the person standing in (about) Las Vegas. That person is standing basically sideways on the earth, therefore his eyes and point-of-view will be tilted sideways:


If we rotate everything around so that person in Las Vegas is now appearing to be level (no longer looking to be standing sideways) we can see the Moon the way THAT person sees the moon -- through his eyes and from his point-of-view. The Moon on the horizon will appear tilted from the point-of-view of that person, because the person himself is tilted:



When we take into account the 23° tilt of the Earth, the Moon will appear higher in the sky in the winter, so A LARGER PORTION of the Moon's path across the night sky is able to be seen in the winter months as opposed to the summer months. Therefore, nighttime Moon at moonrise and moonset will look more tilted in the winter months (because we see a greater portion of its nighttime path).

But (from Las Vegas) the Moon when viewed near the horizon will never have a terminator line that looks completely horizontal, nor will it have one that looks completely vertical. There will always be some tilt.

So to answer your question -- it will always appear "somewhat" tilted on the horizon, but will appear more boat-like in the winter and less boat-like in the summer (and in between otherwise).

Originally posted by luxordelphi
reply to post by CherubBaby

 

Hey Cherub..I thought I would answer your question because no one else has. No...I would have to say that it's not normal. For me, even one month is not normal because Vegas is a long long ways from the equator. Don't be put off by people who just ascribe this to mid-latitude blues. An equatorial moon is a startling sight for us in the mid-latitudes. And month after month of it...more often than not..trippy.

Luxordelphi --

I've explained before why it isn't only the equator that can see a heavily-tilted Moon.

Here is a graphic showing the equator, AND showing the normal 23° tilt of the Earth



In the winter, Earth's equator is actually tilted 23° toward the south -- so at that time, the equator IS NOT aligned with the ecliptic plane, which is more-or-less the point directly beneath the Moon. So in the winter, people at the equator are NOT seeing a completely horizontal boat moon.

The part of the earth that is aligned with the Moon and the ecliptic plane in the winter is actually 23° NORTH of the equator -- in places such as Mexico. So in the Winter, people 23° away from the equator (like parts of Mexico) are the ones seeing the completely horizontal boat moon. NOT the equator.

In fact, Las Vegas being at 36° (13° away from 23° latitude) will see MORE of a boat-looking moon than the people at the equator. In the winter, Las Vegas (being 13° away from the 23° latitude line) should see a moon that is 13° away from being horizontal, while people at the equator (being 23° away from the 23° latitude line) would see a moon 23° away from being horizontal -- although the tilt would be in opposite directions, because Las Vegas is North of the 23° latitude and the equator is south of the 23° latitude.

Something like the OP's picture from November:

Here's what the moon looked like 5 days before and 5 days after the new moon, when it was 5° above the horizon, as viewed from Las Vegas, covering the time period of December 10, 2010 to February 26, 2012:

reply to post by Soylent Green Is People


Soylent: the moon doesn't have a winter path. The moon is not seasonal, it is monthly. It has an 18 year cycle wherein it has reapeated all of it's configurations and gone to the extremes of those configurations and then begins again.

www.umass.edu...

Where to find the Moon in the sky on any given day depends on 3 things: (1) the phase of the Moon on that day (2) where the Sun is in the sky (3) where the Moon is in its 18.6 year cycle

Originally posted by luxordelphi
reply to post by Soylent Green Is People

 

Soylent: the moon doesn't have a winter path. The moon is not seasonal, it is monthly. It has an 18 year cycle wherein it has reapeated all of it's configurations and gone to the extremes of those configurations and then begins again.

www.umass.edu...

Where to find the Moon in the sky on any given day depends on 3 things: (1) the phase of the Moon on that day (2) where the Sun is in the sky (3) where the Moon is in its 18.6 year cycle

Of course the Moon takes different paths across the night sky depending on the season, All you have to do is watch to the Moon to know that.

Due to the tilt of the earth, the Moon is higher in the night sky in the winter than it is in the summer. It is similar to (but opposite) the Sun, which has a path that is higher in the sky in the Summer than it is in the Winter.

Here's a graphic (similar to the one in my post above, but revised slightly) that helps show what I mean:



In the graphic above, the northern hemisphere in the winter is tilted farther south on the night side of the planet, so it is therefore more directly under the Moon; therefore the Moon will in turn appear more overhead in the sky (just like the Summer sun takes a higher path in the daytime sky).

Conversely, in the Summer, the Northern Hemisphere is tiled more to the north on the night side of the planet, and is thus NOT directly under the Moon --- so the nighttime Moon will appear to be lower in the night sky -- with a path staying more toward the South rather than overhead.

Different seasons, different paths.

People have known since ancient times that the path of the Sun and Moon appear higher or lower in the sky depending on the season. Ancient observatories such as Stonehenge work on the basic fact that the Sun will be in a specific part of the sky on the solstice -- a different place in the sky than the other days of the year.

If you don't know that the tilt of the Earth causes the Sun and the Moon takes a different path across our sky depending on the season, then perhaps you should research the subject a bit more.

I ran out of edit time on the above post before I could add this clarification:

Due to the the phases of the moon being in the sky at different times of the month, the seasonal changes in the path of the Moon is not as straightforward as the seasonal changes in the path of the Sun, but those season path changes still happen.

The changes in the path of the Sun occurs constantly and is most noticeable season by season. The cycle of the Sun's path throug hthe sky takes one year to repeat itself. However, the time between the phases of the Moon occurring on the same day of the month is the "Metonic cycle" (the cycle you referred to in your post, but did not name). This cycle takes 19 years to repeat itself (not 18, as you said) but the path of the Moon in the sky is costantly changing (like the Sun) and is also very noticeable season to season. Just because this cycle takes 19 years to repeat itself does NOT mean that the Moon doesn't change its path during that time.

You seem to be misrepresenting or misunderstanding what the Moon's Metonic cycle is. The 19 year Metonic cycle does NOT mean that it takes 19 years for the Moon's path to change.

reply to post by Soylent Green Is People

Of course the Moon takes different paths across the night sky depending on the season, All you have to do is watch to the Moon to know that.

The moon is not seasonal - it does not have a yearly cycle. It has a monthly cycle and an 18.6 year cycle and perhaps longer cycles - these are the two I am familiar with. The sun is seasonal and has a yearly cycle.

www.umass.edu...

As Earth revolves around the Sun with a tilted axis of rotation, Earth's axis always points toward the same direction in space. We know this to be true because Polaris, the North Star, never appears to rise or set, and is always seen in the same place in the sky from hour to hour and night to night as viewed from a particular location.

Like a pendulum, the sunrise direction changes from NE @ summer solstice to SE @ winter solstice, and back to NE, completing one full swing back and forth, or one full cycle, each year. Also like a pendulum, there is a stopping or 'standstill' at the extremes, or solstices. In fact, the word solstice means 'standstill of the Sun'.

The Moon orbits, or revolves, around Earth and completes one revolution in 29.5 days. This is the same length of time that it takes the Moon to complete one cycle of phases. Because of the shorter period of revolution for the Moon around the Earth, compared to the revolution of the Earth around the Sun, the Moon completes between 12 and 13 cycles of lunar phases in 1 year.

The pattern in the Moon's movements is more complex than the Sun's for several reasons: (1) The Moon completes one orbit around us in a much shorter time than 1 year (in 29.5 days or about a month, in fact, in contrast to our orbit around the Sun with a period of 365.25 days).

Because of the rapid orbit of the Moon around us in a plane which is close to the plane in which we always see the Sun, THE MOON DOES IN A MONTH WHAT THE SUN DOES IN A YEAR, in terms of the changing rising and setting direction along the horizon.

That is, the moonrise and moonset directions change like a pendulum, swinging back and forth along the horizon and completing one full swing each month. The Sun's pendulum-like swing continues much slower, with the Sun completing one full swing each year.

Furthermore, the outer extremes of the Moon's monthly range of rising and setting are not fixed, but change slightly from year to year with an 18.6-year cycle.

Another example of the difference between a monthly cycle and a yearly cycle can be taken from a culture that uses a lunar calendar rather than solar. Ramadhaan is a special month for Muslims. Its' date is set by a lunar, not solar, calendar and is different every year when placed within the context of a solar calendar. It is the sighting of the first faint crescent after new moon that signals its' advent.

www.islamweb.net...

The Caliphs and governors of the Muslim states were not too arrogant to accompany judges and ascend high places in order to sight the crescent of Ramadhaan.

During the reign of Sultan Muhammed Al-Naasir ibn Qalaawoon, Ramadhaan came in winter and the sky was completely overcast and cloudy.

Last year in 2011, Ramadhaan was in August because a lunar calendar is not seasonal so this holy month for Muslims is not a winter or summer observance.

www.islamicity.com...

But this year, the calendar has thrown a wrinkle into the date business. It will be the first time in a decade that Ramadan starts before the harvest season in September. The holy month follows the lunar calendar and moves forward each year about 10 days.

The time between the phases of the Moon occurring on the same day of the month is the Metonic cycle (the 19 [not18] year cycle you referred to in your post, but did not name). Just because this cycle takes 19 years to complete does NOT mean that the Moon doesn't change its path during that time.

The phases of the moon do not happen on the same day of the month because months, the way we use them, are based on a solar calendar - a yearly cycle. The moon has no yearly cycle - it has a monthly cycle which does not follow the solar months. The 18.6 year cycle is a cycle of changing variance extremes for the moon - it is not seasonal. It describes the variance in the moon's position which is monthly and describes the build up to greatest variance and the slow down to least variance in this 18.6 year cycle.

(see next post for continuation)

reply to post by Soylent Green Is People


(continued from previous post)

From the first link:

This means that the most northerly and the most southerly rising and setting of the Moon occur every month at the peak of the 18.6 year cycle.

The Moon's 18.6-year cycle peaks in 2006 and 2024-25 (and every 18.6 years thereafter), with observable consequences extending for at least 3 years around the peak year(s).

For the years 2005-2007, and also 2023-2026, EACH MONTH the Moon will rise and set more northerly and ~2 weeks later more southerly than the solar extremes. Also, EACH MONTH the Moon will transit higher in the sky than the summer Sun and ~2 weeks later lower than the winter Sun. This is the MAJOR LUNAR STANDSTILL.

9.3 years after a major standstill, the monthly range of moonrise and moonset shrinks. What we see is that each month the Moon will rise and set LESS northerly and ~2 weeks later LESS southerly than the solar extremes.

reply to post by luxordelphi


lux, you have some good information there, unfortunately you forgot to think it through in regards to the moon's orbit and the Earth as far as what that information is telling you.

It says that the moon goes through its cycle 12-13 times over the time that the sun goes through its changes in path through the sky (a year). Think about that...if the moon follows the same path as the sun through the sky (within 5 degrees of course)...and the Earth is always tilted towards Polaris which causes the orientation of the Earth's tilt to cause it to lean towards the sun or away from it depending on season (and actually the cause of those seasons)...the moon's orbit around the Earth is not oriented with the tilt imparted to the Earth and stays roughly with the ecliptic plane...the plane that the Earth orbits the sun.

So that means that every cycle the moon is in what would be the same as 'summer' path of the sun, which as everyone knows takes the sun pretty much directly overhead in the mid-latitudes DURING THE DAY. However, Day and Night are tied in with the sun...the moon is most visible...at Night...so that means that almost half of its orbit goes by during the day. So if it's summer...the 'summer' path of the sun and the moon through the sky can only occur during the day...During the winter, the 'winter' path of the sun and moon can only occur during the day...because the sun and moon mostly share the same path through the sky. This also means the opposite is true...during the summer, the moon follows the 'winter' path through the sky when it is on the Night Side of the Earth because the Earth is tilted towards the sun...and in the winter, the moon follows the 'summer' path when it's on the Night Side because the Earth is tilted away from the sun. This is also exactly why we have our seasons in the first place and why the length of day and night change throughout the year.

That means that whichever is in its summer path, on the side of the Earth that it is tilted towards...is going to be close to almost directly overhead in the mid latitudes, regardless of day or night. Their actual paths through the solar system doesn't change, but our perspective of them does...the phases of the moon and its position in the sky AT NIGHT are determined by our orbit around the sun and our axial tilt, so regardless of the moon's orbit around the Earth being much shorter than one year...the changes in its phase orientation to an observer are specifically locked to the Earth and sun's one year period.

If the moon happens to be near the horizon from your vantage point when it happens to be going through the 'summer' path through the sky, it will be the closest to a boat moon at that time IF IT IS ALSO NIGHT - because it requires the sun to be below the horizon for the moon to be a crescent in the first place. Again, this should be painfully obvious as to why it can be observed during the winter because the sun is not obscuring the sky and also because the sun is the cause for what part of the moon is lit up from our perspective. It's kinda hard to have a crescent moon pointed down towards the horizon during the middle of the day since that kinda requires the sun to be below that horizon...which is obviously only going to happen at night. The moon is only going to be going through the sun's 'summer' path through the sky at night during the winter.

The moon is only readily visible during the night, so the only time that it gets a chance for its path to line up close to directly overhead (the summer path) AT NIGHT is when the sun is in its winter path.

So while the moon may have a roughly monthly cycle...our day/night cycle is still tied to the sun and therefore the visibility of its phase orientation (because that's how the sun lights it up) is still only going to be visible at night and thusly lock the visible changes to the same cycle as the Earth going around the sun. The moon orbits the Earth, yes, but the plane of its rotation is on the Ecliptic...just like pretty much every other major body in the solar system, including the Earth...we are just viewing it from a changing perspective because the Earth doesn't sit perpendicular to the ecliptic, but is instead tilted by 23 degrees.

And seriously Cherub...how many topics about this do you really have to make before you actually listen? Do we really have to wait until summer for you to realize you don't know what you're talking about and what you're seeing is perfectly normal?

Edit - or are you just going to regale us with photos from the southern hemisphere during the northern summer and ignore the fact that they are proving what we've been telling you in several threads now?

I had a co-worker not that long ago that didn't know that the seasons were tied to the Earth's axial tilt...he had been taught that it was all tied to our orbit and that was it...is that why this is hard to understand? Did your teachers fail you as well?

reply to post by Dashdragon

So that means that every cycle the moon is in what would be the same as 'summer' path of the sun, which as everyone knows takes the sun pretty much directly overhead in the mid-latitudes DURING THE DAY.

The sun is directly overhead at the equator on the equinoxes and travels as far north and south as the Tropic of Cancer and the Tropic of Capricorn where it is directly overhead on the solstices. It is never directly overhead in mid-latitudes unless, as now, something fundamental has changed.

geography.about.com...

On the equator, the sun is directly overhead at noon on the two equinoxes - near March and September 21.

The Tropic of Cancer and the Tropic of Capricorn each lie at 23.5 degrees latitude. The Tropic of Cancer is located at 23.5° North of the equator and runs through Mexico, the Bahamas, Egypt, Saudi Arabia, India, and southern China. The Tropic of Capricorn lies at 23.5° South of the equator and runs through Australia, Chile, southern Brazil (Brazil is the only country that passes through both the equator and a tropic), and northern South Africa.

The tropics are the two lines where the sun is directly overhead at noon on the two solstices - near June and December 21.

...during the summer, the moon follows the 'winter' path through the sky when it is on the Night Side of the Earth because the Earth is tilted towards the sun

The moon has no winter path. It is not seasonal/yearly. It is monthly and has an 18.6 year cycle wherein its' variances go to extremes both greatest and least. A calendar based on lunar cycles does not follow a solar calendar. They diverge, if started at the same moment, by greater and greater amounts.

so regardless of the moon's orbit around the Earth being much shorter than one year

The moon's orbit around the earth is not 'much shorter than one year.' The moon's orbit around the earth is 29.5 days. The earth's orbit around the sun is 365 plus/minus days. There is not a comparison here.

www.umass.edu...

From day to day, the Earth revolves, or orbits, around the Sun in a plane which we call the ECLIPTIC, completing one orbit around the Sun in a time we call the YEAR.

The Moon orbits, or revolves, around Earth and completes one revolution in 29.5 days.

If the moon happens to be near the horizon from your vantage point when it happens to be going through the 'summer' path through the sky, it will be the closest to a boat moon at that time IF IT IS ALSO NIGHT

The moon has no summer path. It is not seasonal or yearly. It is monthly and 18.6 years to complet its' equivalent of the solstices and equinoxes.

because it requires the sun to be below the horizon for the moon to be a crescent in the first place.

The phases of the moon are the same all over the world. The reason the crescent is not visible until it's visible is because the moon is too close to the sun to see it. It doesn't mean it's not happening and some, with better eyesight, are able to spot the waxing crescent before others.

museumvictoria.com.au...

The phases of the Moon are the same all around the world.

The moon is only readily visible during the night

The moon is visible during the day every month.

www.physics.ucla.edu...

Even many adults do not realize that the moon is often visible in the daytime. The moon is visible sometime during the day for most of the month, except near new moon, and right at full moon.

Originally posted by luxordelphi
The moon has no winter path.

solarsystem.nasa.gov...

starchild.gsfc.nasa.gov...

Uh-oh. My links have "nasa" in them. *Gasp* Burn the witches!

reply to post by ColAngus

Uh-oh. My links have "nasa" in them. *Gasp* Burn the witches!

The winter/summer moon path drawing (the same in both your links) is also repeated in two Cornell links, one of which:

curious.astro.cornell.edu...

has this to say:

the Moon seen in the Southern hemisphere is upside down when compared to that seen in the Northern hemisphere. This means that if the concave part of the crescent points "left" in North, it will point "right" in the South. Since the transition from a "left" pointing crescent to a "right" pointing one must be smooth, we require that the Moon be a "boat" instead of a crescent at the equator.

and this:

The Moon's path (and thus appearance in the sky) will depend on the season.

The moon's path is not seasonal because the lunar month, upon which a lunar calendar is based, does not coincide with the solar based months of our calendar. The dates slip away from each other over time. Full moon does not fall on the same date every month. The APPEARANCE (whether it shows up or not) of the moon in certain latitudes is dependant on the seasons but not by virtue of the moon's path.

www2.gi.alaska.edu...

Has it crossed your mind that the moon has been exceptionally noticeable this winter? It has, and there's a reason for it. We're at the peak of an 18.6 year cycle during which the moon's course rhythmically rises and drops in the sky.

During the winter of 1986, we are passing through a period when the moon is at one extreme in its precession cycle. The full moon is now higher in the sky than it will be at any other time during the next 18.6 years.

Above a certain latitude, the full moon will just skim the northern horizon and never set. This means that the motion of the full moon this winter is similar to that of the sun in the summer. At high latitudes like Alaska, the winter full moon rises very high into the sky and practically never sets. In the summer the opposite is true, and the full moon practically never rises.

We're all familiar with the Arctic Circle, above which the sun never rises during the winter months and never sets during the summer. Few of us stop to consider that a similar situation prevails for the moon. However, the lunar Arctic Circle is not fixed like the solar Arctic Circle, but changes its latitude with pendulum-like regularity over the years.

The lunar Arctic Circle is now near its southernmost position, so the full moon never sets for most Alaskans. It swings down in the north (like the midnight sun), but never sets for observers living north of, say, Wasilla.

In about another nine years, or half of the moon's precession period, you won't be able to see the full moon for a full 24 hours from anyplace south of the latitude of Barrow.

But the latitude parameters fluctuate and are set not seasonaly but in an 18.6 year cycle which is a path of the moon just as the lunar month is a path. This path does not depend upon a yearly cycle because the year belongs to the sun and the moon has its' own path.

And here someone has done the math on the extreme variance of the 18.6 year cycle for the limits of lunar visibility in the arctic.

www.xefer.com...

The lunar inclination is approximately, 5° 8′. So, given the tilt of the Earth’s axis, 23° 26′, this puts the lunar Arctic Circle at 90 – (23° 26′ + 5° 8′) or 61° 28′. Given the right circumstances the Moon would thus be visible due north at that latitude; any further south and it would dip below the horizon.

So, while the limit of the lunar Arctic Circle is 61° 28′, it only reaches that latitude once every 18.6 years.

reply to post by luxordelphi


lux...you toss around too much information about this in order for you to be this willfully ignorant of how all this works.

The only reason why my previous post was as long as it was, was to purposely try and overly explain the seasonal changes to the position of the moon in the NIGHT sky. Yes of course the moon is visible during the day at times, but you cannot get your boat moon during the day because by the very definition of the phase orientation of the moon to call it a 'boat' moon, requires that the crescent be pointed towards the horizon, which can only happen if the sun is below the horizon and if the sun is below the horizon, that's sort of why night happens, now isn't it.

And seriously...with all the touting of Cherub's pictures in Las Vegas of the boat moon as if they were 'perfect' boats, when it's off by about 15 degrees (exactly as everyone has been telling you it should be for months now), then I can refer to the summer path of the sun at that latitude as being directly overhead by the same generalization. You can't get nit picky with one person's description and completely fudge the details on the info you're trying to use to support your argument at the same time. Unless you two are just purposely in this to mess with people and are just trolls of course.

I mean, I said that the moon's orbit is indeed way less than a year with it completing 12-13 cycles per year...how is that different than what you said? Oh that's right, you're trying to twist the truth to your own agenda. Let's do some simple math for you...365 (we'll leave out the .24 on there, so don't even think about jumping on that) divided by 12 is 30.41, and 365 divided by 13 is 28.07. Hmmm that looks pretty darn close to averaging to the actual orbital period of the moon around the Earth now doesn't it? So how was I incorrect? Oh yes...you're simply cherry picking things to troll with.

Even my kids know that you mostly (that's MOSTLY...not only) see the moon at night because the sun is too bright and either washes it out, or the lit-up side of the moon is not oriented enough towards us.

How many times do people need to draw you little diagrams of the Earth, moon, and sun for you to understand how this all works? It doesn't require a degree in astrophysics to understand the seasonal - aka yearly - changes in the sun and moon's positions in the sky. Yes the moon orbits the Earth on a cycle slightly less than a typical month, but I'd love to see an explanation as to how what part of the sky that is visible at night, and thereby what part of the moon's orbit around the Earth that's visible at night, is not tied in with the Earth's yearly orbit around the sun.

It's not just the matter of the moon's orbit around us that determines these things...but what part of the universe is on the opposite side of the Earth from the sun...aka the Earth's night side..that determines what part of the moon's orbital period is visible at night on Earth. Since this changes on a yearly cycle that should be fairly simple to see that the moon's position and our perspective of it at night has a lot to do with where the sun is in relation to the Earth, which changes on a yearly cycle.

The Earth is tilted towards a roughly fixed point in space (which is regulated largely by the moon's orbit around the Earth..which is further proof that all is well). This point has the Earth tilted at roughly 23 degrees in relation to its orbit around the sun.



The moon does not follow the Earth's tilt, but is instead lined up with the ecliptic (which means it does not orbit around the Earth's equator...to reiterate that for the billionth time) with a 5 degree variation that is on your other almost 19 year cycle you keep mentioning.

There is more than enough proof to show that these things have been like this for a long time, and with what I've seen of the posts from you and Cherub and how you try to slide from one point to another just to keep the multiple threads alive I really think you are more than aware of this. I'm even willing to say that you probably knew this before any of these threads and all of these explanations from those of us fool enough to indulge you.

On top of everything there's also the simple fact that if the moon's orbit around the Earth did suddenly just go crazy, in the period that Cherub has been making these troll threads that you have been helping escalate, there would be no denying the tidal waves and earthquakes that would have already long since devastated large parts of the globe.

Originally posted by luxordelphi
The moon's path is not seasonal because the lunar month, upon which a lunar calendar is based, does not coincide with the solar based months of our calendar. The dates slip away from each other over time. Full moon does not fall on the same date every month. The APPEARANCE (whether it shows up or not) of the moon in certain latitudes is dependant on the seasons but not by virtue of the moon's path.

Yes. This is obviously true. One lunar cycle (say full moon to full moon) does not perfectly coincide with the calendar months, but rather is about 29 days. So a full moon never occurs the same day each month, or the same day of a particular month year to year. Although, as you said, the dates that a given moon phase will occur will repeat itself in an 19 year cycle (i.e., the dates of the moon phases in 2012 coincide with the dates of the moon phases in 1993, and in 2031. For example, there was a full moon on February 7 in 1993 and in 2012, There will also be a full moon on February 7, 2031 -- 19 year intervals.)

That's all well and good, and I never said I disagreed with that.

However, that still doesn't negate the fact that in general, the nighttime path of the Moon will look higher or lower in the sky depending on the season. That 18.6 year cycle may affect the exact path of the nighttime moon, but that doesn't mean the path still does not change seasonally.

The Information you posted does not contradict what I said. The bottom line is this:

Due to the tilt of the Earth, any particular phase of the moon occurring within a couple of weeks of the winter solstice will take a different path across the nighttime sky than that same phase of the moon occurring within a couple of weeks of the summer solstice.

For example, the first full moon after the Summer solstice this coming year (full moon occurring on July 3rd, which is 13 days after the solstice) will be much lower in the sky than the first full moon after the winter solstice (full moon occurring Dec. 28, which is 7 days after the solstice). Different seasons; different paths across the Earth's sky for the Moon.

The stuff you posted about the 18.6 year cycle, or the location on Earth of the lunar arctic circle does NOT contradict this. The location of the Moon in the night sky may vary slightly over this 18.6 year cycle, but the location of the Moon as seen from earth will still change seasonally, even considering the 18.6 year cycle.



EDIT TO ADD:
After I read what you said, I think you may be misunderstanding what I am saying. I noticed you said this:

The APPEARANCE (whether it shows up or not) of the moon in certain latitudes is dependant on the seasons but not by virtue of the moon's path.

Perhaps there is some confusion about what I mean when I say the "Moon's path". I'm talking about the path the Moon takes across the Earth's sky as it appears to an observer on the Earth. Perhaps you think I am talking about the orbit of the Moon in space? Well, I'm not. I'm talking about what the Moon's path in the Earth's sky looks like from Earth. THAT'S what changes seasonally.

Luxordelphi --

I made another graphic showing how the seasonal difference in relative tilts of the Earth will cause the perspective of the Moon to look different from a given point on Earth.

Based on the image below, how can you say that a given phase of Moon (a full moon, for example) will not look to be in a different part of the sky in winter when compared to summer, based on the difference in perspective of the person observing it?:



EDIT TO ADD:
This graphic is simplified for clarity purposes and does not show the 5° inclination of the Moon's orbit (as stated in the post below by nataylor), which as luxordelphi pointed out, changes over an 18.6 year cycle. However, the seasonal difference in the location of the moon as seen from the perspective of a person on Earth caused by the tilt of the Earth is greater than this 5° inclination and the 18.6 year cycle. Therefore for clarity purposes, this graphic ignores it.

Including it would just make the image too busy and confusing. The graphic as it is drawn now gets across the general idea of what I'm saying.

Originally posted by luxordelphi
The moon's path is not seasonal because the lunar month, upon which a lunar calendar is based, does not coincide with the solar based months of our calendar.

The moon's path is, of course, generally seasonal. Since the inclination of the moon's orbit to the ecliptic is about 5°, the moon will never be more than 5° from the path of the ecliptic. And since the ecliptic moves with the seasons, so will the moon's path. Yes, there is an ~18 year cycle were the moon goes from 5° above the ecliptic to 5° below the ecliptic back to 5° above the ecliptic. But that total change of 10° is small compared to the seasonal movement of the ecliptic, which is almost 47°.

In other words, viewed from Las Vegas, on the summer solstice, the moon will be somewhere between ~72° and ~82° at its highest point in the sky. On the winter solstice, it will be somewhere between ~25° and ~35° at its highest point in the sky. Where it is in those ranges depends on where the moon is in its ~18 year cycle. But as you can see, even at its highest possible point on the winter solstice, it will still be far below the lowest possible point on the summer solstice. Thus, the moon's path is indeed seasonal.

reply to post by nataylor


Which we must keep in mind that the season path of the moon is moreso the seasonal orientation of the night side of the Earth. The moon is simply following the same path it does throughout the rest of the year, but as the Earth's position in its orbit causes our view of the night sky to shift it puts a different part of the moon's orbit on the night side of the planet.

reply to post by Dashdragon

The only reason why my previous post was as long as it was, was to purposely try and overly explain the seasonal changes to the position of the moon in the NIGHT sky.

The moon is not seasonal - it is lunar monthly and 18.6 years.

www.skyscript.co.uk...

The lunar year, that is twelve lunations, takes 354 days to complete, whilst the solar year over-runs by about a further 11 days to give 365 days.

Trying to fit lunations into a solar year and make the moon seasonal based on the seasons of a solar year doesn't make any sense because the moon has its' own cycles as we have discussed.

Yes of course the moon is visible during the day at times, but you cannot get your boat moon during the day because by the very definition of the phase orientation of the moon to call it a 'boat' moon, requires that the crescent be pointed towards the horizon, which can only happen if the sun is below the horizon and if the sun is below the horizon, that's sort of why night happens

The thin waxing crescent is out during the day. In its' first few days it is difficult to see because it is close to the sun. It is normally observable first at twilight when the sun has set and when there is enough separation between the sun and the moon to make it visible. Twilights and their different grades and qualities are discussed in Naval manuals and Islam has quite a few more subtleties and grades to twilight than the Navy and they each have their own definitions. Twilight and its' qualities and grades is also subject to latitude as far as duration and quality of light.

www.usno.navy.mil...

www.al-islam.org...

The waxing crescent becomes easily visible during the day as it increases in light, however, the angle of tilt constituting the boat moon (horned moon, smile moon, Cheshire moon, equatorial moon, smiley face moon etc.) needs a horizon to determine. When the waxing crescent is high in the sky there is no way, by naked eye observation alone to tell whether or not it is a boat moon. I don't know if this is what you were trying to say or not because your posts are confused.

And seriously...with all the touting of Cherub's pictures in Las Vegas of the boat moon as if they were 'perfect' boats, when it's off by about 15 degrees

It's not off by 15 degrees but is and continues to be a perfect boat month after month. The photos in this thread and in the other thread - The moon is upside down tonight in Las Vegas - show perfect boats from varied latitudes, none of them on the equator nor even close to it.

Let's do some simple math for you...365 (we'll leave out the .24 on there, so don't even think about jumping on that) divided by 12 is 30.41, and 365 divided by 13 is 28.07. Hmmm that looks pretty darn close

I'd stay away from the math if I were you. It's a difference of 11 days. There is no comparison between a lunar cycle and a solar cycle except in 3 body computations. The moon is not seasonal in the sense that the sun is.

Even my kids know that you mostly (that's MOSTLY...not only) see the moon at night because the sun is too bright and either washes it out, or the lit-up side of the moon is not oriented enough towards us.

Here's for the kids:

www.planetary.org...

Having said that, I do want to explain why this is a button of mine, why I am bothered by incorrect representations of lunar phases even in silly children's books.

Children are natural scientists. They are constantly learning through observation, seeing things out there in the world and constructing an understanding of how everything works. The Moon is something that they notice; "Moon" was one of my older daughter Anahita's earliest words (something I've written about before). Typically, when my kids notice the Moon, it's bright daylight, because we're not often out after dark. From babyhood Anahita and Sanaya learned by assembling the evidence they've seen with their own eyes that the Moon is there in the day and there at night too, but it's in different places and appears different shapes on different days.

Anahita knew this, yet somewhere in her third year she learned from book after book that the Moon is a nighttime object, the complement to the Sun, the yin to the Sun's yang, rising in any of its possible phases when the Sun sets. This, of course, is wrong, and directly contradicts the evidence she's seen with her own eyes, but it's what she was taught, so it's what she learned.

(continued next post)