14th December 2012 Go Outsie and Look at the Mon=on!

The vast majority of moon phase calendars have no idea where you are or when you are observing the Moon and are thus unable to show you whether it will appear upright or tilted.

EVERYTHING in the sky including the Moon is subject to a trick of perspective known as field rotation. Basically, in the Northern hemisphere they appear to undergo a clockwise rotation while up in the sky. When you see the Moon rise and are looking East it appears to be rotated to the left. It appears upright when high in the sky and you are looking South and when it sets it appears rotated to the right and you are looking West. The amount of apparent rotation varies based on the observer's latitude and time of year as the Moon and Sun's orbits vary.

How do we know they aren't real rotations? First, the North pole of the Moon always still points to the North. Second, YOU are the one turning. Third, when you see it setting, appearing to be rotated to the right and you are looking West, someone on the other side of the world AT THE SAME TIME can see it rising and appear to be rotated to the left. If it was a real rotation then both observers would see it rotated the same direction at the same time. They do not.

Because the amount of tilt is not the same for ever observer. A static chart has no idea what your location is or when you are observing.

Tonight I took another shot of the moony and this time it cme out a little better.

It was on maximum zoom, so you don't have a frame of reference, but I was stoop up with the camera line at the horizon....

[link to postimage.org]

The moon is still in the west, far above the horizon, and you can see the entire outline.

Today the colour is brighter than yesterday. now check the moon phase calender and compare...

[link to postimage.org]

Although theabove link says that the phases are approximations, I do not think they would be off by a whole 90 degrees.

Also if this is a Cheshire or Wet Moon, then why has it not been factored into the calender?

Worked OK yesterday but no matter, above is the moon as I see it

Hey Weasel, can you get a pic from where you are so we can see just how much of a difference there is between your country and mine?

Because AGAIN the calendar does not know where you are or when you are looking. if you were to observe the Moon a few hours earlier then it would appear upright. If you were to observe even earlier than that when it rose it would appear with the lit side up. the further North you are the less apparent tilt you would see. If you were in the Southern hemisphere you would see the apparent tilt in the other direction. If you observe through a telescope which is polar aligned then it would always be upright.

Cloudy and raining righ now in Indianapolis. Even if it wasn't I don't have a good camera that wouldn't show it extremely overexposed. Stellarium should be able to show you the difference though.

So you are saying that if I go out at the same hour every night, I should always see a wet moon during the new moon phase?

....and the fact that it is very near right now is due to perigee as of the 14th, which I understant, but what I would like to confirm is that you will never see a wet moon based on you're location?

No. If you go out at the same hour every night the moon will be progressively higher in the sky. It sets about 50 minutes later each day. The apparent tilt is greatest when near setting. Plus, as it progresses through its phases its orbit also takes it further North and South (it goes from full North to full South each month) and its relationship to the Sun will change. If you look at the crescent about the same time each month through the winter months you'll see similar tilts and you can see tilts on other phases other times of the year. The closer you are to the equator the more you'll see an apparent tilt. But again this is because YOU are turning. When you see it upright you are looking South. When you see it tilted and setting you are looking West.

It all depends on your latitude, time of observation, and time of year. I'm at about 40 degrees latitude and it was very tilted last night. I've seen it before and I'll see it again. The further North you get the less apparent tilt you'll see. Perigee doesn't have much to do with it.

Well thanks for clearing the doubts, live long and prosper!