Tonights unusual Moon

[Orion_the_Hunter]

Hi, I'm a bit puzzled by tonights Moon. I have attached a sketch to explain what I mean:

Normally from here it looks like the picture on the left, this evening it looked more like the one on the right (ie more like a 'smile' than a backwards 'C'.)

The Moon was low in the sky and also had a bit of Earthshine even though the sky was dark.

My location is 43N 3E.

Surely the Moon should only look like the pic on the right if I was suddenly transported to somewhere nearer to the Equator???

Did you have this effect in the UK too?

What would cause this?

Sorry I couldn't get an actual photo, I didn't have a camera nearby.

Thanks.

ps I have also posted this elsewhere on the forum but I thought I'd get more response here.

[barkis]

The Old moon in the new moons arms.

The saying that describes the earthlit part of the moon, cradled in the early new moon crescent.

The moon appears to rotate as it moves across the sky.The crescent will seem to turn clockwise as the earth rotates from west to east. It is caused by our viepoint from a curved surface. The Earth.

The same effect occurs with the constellations.

If you observe Orion rising in the East, he will be lying on his right side. As the earth rotates, he will gradually straighten up, until when on your local meridien, he will stand upright. As the night progresses, he will lean to the right, and disappear in the western horizon, lying on his left side.

Ron.

[laser_jock99]

Could be to do with the angle of the ecliptic in relation to the horizon? Can vary enormously with the time of year, even looking in the same direction.

[Pete Presland]

The Old moon in the new moons arms.

The saying that describes the earthlit part of the moon, cradled in the early new moon crescent.

Ron.

what a great saying, never heard that before

[BinocularSky]

Could be to do with the angle of the ecliptic in relation to the horizon?

Yes, that is exactly right. At the time of waxing crescent moonset, the ecliptic is at a very steep angle to the horizon at this time of year. You have a similar situation with waning crescent moonrise in late July-late August. At the moment, the Moon is quite far north of the ecliptic, so it is slightly higher in the sky than it would be if it was on the ecliptic; this makes the "chalice" effect slightly more noticeable.

[661-pete]

Yes, knowing the seasonal changes in the angle of the ecliptic is very important, especially for evening and morning planetary observations. Especially with Mercury, by far and away the hardest of the bright planets to observe. The general rule is: look for Mercury in the early evening in the Spring, and in the early morning in the Autumn*. These are the times when the ecliptic is most steeply inclined to the horizon.

Certainly I have never seen Mercury in the opposite extreme conditions: i.e. in the evening in Autumn, or in the morning in Spring.

At present we are still closer to the winter solstice than we are to the Spring equinox, but the ecliptic orientation is still favourable. The altitude of the Moon is also enhanced by its orbit taking it some way north of the ecliptic at present.

*Obviously you also need to check ephemerides, and pick a date when Mercury is at a greatest Eastern elongation (for evening observation) and a greatest Western elongation (for mornings). Also, these 'rules' apply equally to the Southern Hemisphere, although of course the dates are different!