Debunked: The moon is tilting

Astro

Senior Member
I just completed and uploaded episode 2 of the Youtuber's Guide to Astronomy, this time focusing on claims that the moon is tilting abnormally in the sky.

I believe this claim is best handled in a more qualitative fashion, so I'll let the video speak for itself, but I would like to mention that I have a very high resolution (2400x3000) scan of NASA photo 108-KSC-71P-74 courtesy of the public affairs office in case anyone wants it. I also want to give very special thanks to Lee Keith for providing information about his photo as well.
 
but I would like to mention that I have a very high resolution (2400x3000) scan of NASA photo 108-KSC-71P-74 courtesy of the public affairs office in case anyone wants it. I also want to give very special thanks to Lee Keith for providing information about his photo as well.

Can I get that and post it here?
 
Can I get that and post it here?

Sure, here's a link:
[link removed]
You may want to set up a dummy email address to use to get the file so that you don't get spammed. This raw TIFF file is rather large at 6.9 megabytes so this seemed to be the best solution to send it.
 
The waning moon this morning in the east - it's currently rising slightly north of the sun, and the crescent is almost horizontal - the right side (closest to the sun) is perhaps 20 degrees above the left.
I'm halfway down the east coast of Australia (near Byron Bay) about -30 degrees latitude, and we just started autumn.

So if I was standing in the same positive latitude in North America (the same distance from the equator but above it) would the waning moon look the same at sunrise, or is it just for me at the moment?

Edit... while I was staring at the moon I thought I saw a pinprick of light fly into the moon, then I moved my eye to the other side to track it, and saw the same light 'fly out' of it. I thought it was a satellite, but then I noticed similar light spots anywhere I looked at the sky long enough. It was my eyes.
 
The waning moon this morning in the east - it's currently rising slightly north of the sun, and the crescent is almost horizontal - the right side (closest to the sun) is perhaps 20 degrees above the left.
I'm halfway down the east coast of Australia (near Byron Bay) about -30 degrees latitude, and we just started autumn.

So if I was standing in the same positive latitude in North America (the same distance from the equator but above it) would the waning moon look the same at sunrise, or is it just for me at the moment?

No, because you are 60 degrees away from "vertical" relative to North America. The crescent of the moon is a fixed position, but you are leaning over.

View (today) from Australia:



View from the US


And that would be the same from Japan.

"Up" is a bit of an arbitrary concept in space.
 
Last edited:
So your boat moon would be in your autumn?

A boat moon is when the crescent moon coincides with a steep ecliptic. The steepest ecliptics are during winter

The Ecliptic is roughly the plane of the solar system, so the path the sun and the moon take though the sky, although the moon varies from it by five degrees.
 
The waning moon this morning in the east - it's currently rising slightly north of the sun, and the crescent is almost horizontal - the right side (closest to the sun) is perhaps 20 degrees above the left.
I'm halfway down the east coast of Australia (near Byron Bay) about -30 degrees latitude, and we just started autumn.

So if I was standing in the same positive latitude in North America (the same distance from the equator but above it) would the waning moon look the same at sunrise, or is it just for me at the moment?

Edit... while I was staring at the moon I thought I saw a pinprick of light fly into the moon, then I moved my eye to the other side to track it, and saw the same light 'fly out' of it. I thought it was a satellite, but then I noticed similar light spots anywhere I looked at the sky long enough. It was my eyes.

Here's a tool you might find useful:

This spreadsheet will calculate the exact angle of the moon's tilt relative to the horizon for a given time and location (remember to convert date and time to UT and give your latitude as W longitude, or input E longitude as negative). As Mick pointed out, the moon will not look the same from North America or even if you reversed your latitude to positive from negative. The tilt will be angled opposite as seen in his pictures, but not necessarily be tilted to the same degree. From Byron Bay, depending on the time you were watching it this morning, the moon was tilted anywhere from 23 degrees shy of horizontal as it rose to a minimum of less than 10 degrees shy of horizontal (though the latter occurred well after sunrise and would therefore be harder to see). Now at the same time as it was about 20 degrees from horizontal as you described, if you reverse your latitude to positive you will see that it was about 37 degrees shy of horizontal. The degree of the moon's apparent tilt to the horizon is highly location and time-dependent.
 
I use Stellarium, which is free.
http://www.stellarium.org/



You can print up the Date/Time window and location window, then focus on the moon, and just click anywhere on the map to see what the moon look s like at that point from that location.

The apparent tilt of the moon will vary by 180 degrees from the north to south poles of the earth, assuming you can actually see it.
 
Last edited:
Well playing around with it, I can see that the moon is directly above the rising sun and most horizontal closer to the equator - the further north I go the moon moves to the right of the sun and the left horn climbs higher, the further south I go the opposite.

It's elementary stuff I know, but kind of mind-bending all the same, getting a sense of the fact that I'm really living on a large sphere with things going around in regular cycles.
The hard thing is getting sense of the highly relative nature of reference points and shifting your mind around the various ones.
I'll just call where I'm standing the centre of the universe and leave it at that. ;)
 
Well playing around with it, I can see that the moon is directly above the rising sun and most horizontal closer to the equator - the further north I go the moon moves to the right of the sun and the left horn climbs higher, the further south I go the opposite.

And remember it's only changing because you are having to lean more because of gravity. Your actual position change has very little effect.

If you have a Mac, then Cosmographia is a wonderful way of getting sense of perspective on the Solar System and the relative positions of things. $10 though

https://itunes.apple.com/us/app/cosmographia/id451087543?mt=12

Here's the Moon (on the right) with earth to the left of it and the sun in the distance.



Imagine a little guy standing on the poles, and at the equator, looking at the moon.
 
Last edited:
Here's a tool you might find useful:

This spreadsheet will calculate the exact angle of the moon's tilt relative to the horizon for a given time and location (remember to convert date and time to UT and give your latitude as W longitude, or input E longitude as negative).


Is this spreadsheet publically available - I have an photograph I'm analysing, and this would save me a bunch of time
 
It is still publicly available. The link is in the show description: http://dropcanvas.com/0hn26

You need to download it (right click and "save as") and not just open it or otherwise it will open as read only.
Thanks Chew! That is the link to the spreadsheet. It seems like dropcanvas landed on google's "unwanted software" list? Anytime I try to download any of my own spreadsheets from dropcanvas I now get warnings in Firefox. Anyone else have this problem? Anyone can upload anything to dropcanvas so I wonder if people were abusing it and the whole domain got flagged by google.
 
Back
Top