Different orientations of the Moon

A lot of people have been posting photos of the recent full moon on Flickr,
and we're beginning to notice something that's hard for us amateurs to
explain. It's simply that the moon appears at different orientations on
different nights, even when photographed from the same location.

Obviously it will look different if you move further south, and we're not
surprised when we see photos taken in Australia, but for example, my partner
took this photo - http://www.flickr.com/photos/oricmuso/3185316729/ - on
January 9th this year. I took this one -
http://www.flickr.com/photos/oricmuso/3185316729/ on January 1st 2007 in
exactly the same location, and this one
http://www.flickr.com/photos/allybeag/345249495/ just 3 days later on the
4th. I'd have expected them all to be oriented the same way. Notice, also,
the comments under the first photo, showing moons photographed in Romania
and Japan.

I've been looking at the moon all my life, but never noticed until now how
it seems to be oriented differently from day to day. I'm sure there's a
straightforward explanation for this, but I can't figure it out. (I don't
think it's anything to do with the way the camera was held, though certainly
only some of the pics used a tripod.) Can anyone with a bit more
astronomical education behind them help, please?

Thanks.

ally

"a l l y" wrote in message
...
A lot of people have been posting photos of the recent full moon on Flickr,
and we're beginning to notice something that's hard for us amateurs to
explain. It's simply that the moon appears at different orientations on
different nights, even when photographed from the same location.

Obviously it will look different if you move further south, and we're not
surprised when we see photos taken in Australia, but for example, my
partner took this photo -
http://www.flickr.com/photos/oricmuso/3185316729/ - on January 9th this
year. I took this one - http://www.flickr.com/photos/oricmuso/3185316729/
on January 1st 2007 in exactly the same location, and this one
http://www.flickr.com/photos/allybeag/345249495/ just 3 days later on the
4th. I'd have expected them all to be oriented the same way. Notice, also,
the comments under the first photo, showing moons photographed in Romania
and Japan.

I've been looking at the moon all my life, but never noticed until now how
it seems to be oriented differently from day to day. I'm sure there's a
straightforward explanation for this, but I can't figure it out. (I don't
think it's anything to do with the way the camera was held, though
certainly only some of the pics used a tripod.) Can anyone with a bit more
astronomical education behind them help, please?


As well as the location on Earth, it'll depend when you took the photo
during the night (unless you are using an equatorial mount on a tripod). .
If you use Mare Crisium as a guide, this is the upper-right-most feature on
the photo taken on 1/1/2007 and this is on the eastern hemisphere of the
moon, not too far above the moon's equator (about 17 degrees).

The moon rises with its eastern edge appearing first (pointing upwards), and
through the night it rotates clockwise so that when it sets the eastern edge
is downwards. Thus the Mare Crisium will be on the upper side of the FULL
moon in the early evening, at the right hand side of the FULL moon at
midnight and on the lower edge as the FULL moon sets in the morning.
Assuming the camera has the bottom of the frame roughly parallel to the
horizon, the image will appear rotated depending on when it was taken.

If you check the timing of the photographs you'll see that some of the
images were taken after midnight and others were taken about 6 hours earlier
in the evening. Compare the timing and the orientation and you should see
how the orientation* varies.

The word 'Orientation' itself comes from the action of determining the
direction of the East.

Wasn't it a l l y who wrote:
A lot of people have been posting photos of the recent full moon on Flickr,
and we're beginning to notice something that's hard for us amateurs to
explain. It's simply that the moon appears at different orientations on
different nights, even when photographed from the same location.

Obviously it will look different if you move further south, and we're not
surprised when we see photos taken in Australia, but for example, my partner
took this photo - http://www.flickr.com/photos/oricmuso/3185316729/ - on
January 9th this year. I took this one -
http://www.flickr.com/photos/oricmuso/3185316729/ on January 1st 2007 in
exactly the same location, and this one
http://www.flickr.com/photos/allybeag/345249495/ just 3 days later on the
4th. I'd have expected them all to be oriented the same way. Notice, also,
the comments under the first photo, showing moons photographed in Romania
and Japan.

I've been looking at the moon all my life, but never noticed until now how
it seems to be oriented differently from day to day. I'm sure there's a
straightforward explanation for this, but I can't figure it out. (I don't
think it's anything to do with the way the camera was held, though certainly
only some of the pics used a tripod.) Can anyone with a bit more
astronomical education behind them help, please?

One way to understand what's going on is to imagine that the Moon is
glued to the celestial sphere. As the sky does this:
http://www.robertreeves.com/star_tra...06_9pm-6am.jpg
the Moon goes round with it, changing not only position but orientation.

Of course, it's your camera that's actually revolving, because you've
mounted it on a revolving Earth

--
Mike Williams
Gentleman of Leisure

In uk.sci.astronomy message , Sun, 11
Jan 2009 23:16:39, a l l y posted:

A lot of people have been posting photos of the recent full moon on Flickr,
and we're beginning to notice something that's hard for us amateurs to
explain. It's simply that the moon appears at different orientations on
different nights, even when photographed from the same location.


To tell from its appearance whether the Moon is waxing or waning,
observe whether it looks more like a "C", with horns to the right, or
like a "D", with horns to the left. Ignore the terminator, the line on
the Moon between light and dark; concentrate on the illuminated part of
the circular edge of the visible Moon. Now remember, firstly, that C is
for Crescendo and D is for Diminuendo; and, secondly, that in the
Northern part of the world, it is in fact the other way round.

Reference : Bernard Wicksteed, "It's Fun Finding Out" p.159 foot; book
pub. The Daily Express (London) 1947; will have been in the newspaper
c.1946.


If a crescent Moon is seen in the evening after sunset, it will be
waxing : between New Moon and First Quarter. If it is seen in the
morning before sunrise, waning : between Last Quarter and New Moon.


The line perpendicular to the middle of the terminator points along the
path of the Moon's travel, approximately, since the angle between the
orbital planes of the Earth and the Moon is only about five degrees.
The line of the intersection of the orbits rotates with a period of
about 18.6 years; therefore, the Moon's apparent path varies
significantly from year to year.

--
(c) John Stockton, nr London, UK. Turnpike v6.05.
Web URL:http://www.merlyn.demon.co.uk/ - w. FAQish topics, links, acronyms
PAS EXE etc : URL:http://www.merlyn.demon.co.uk/programs/ - see 00index.htm
Dates - miscdate.htm moredate.htm js-dates.htm pas-time.htm critdate.htm etc.

a l l y wrote:


I've been looking at the moon all my life, but never noticed until now how
it seems to be oriented differently from day to day. I'm sure there's a
straightforward explanation for this, but I can't figure it out. (I don't
think it's anything to do with the way the camera was held, though
certainly only some of the pics used a tripod.) Can anyone with a bit more
astronomical education behind them help, please?

It's not just the moon that seem to be wobbling, it's the whole sky.
You can check the angle between a line through two known stars and the
horizon hour by hour and you'll notice this.
But of course, it's wobbling only relative to your horizon.

Most planetarium software can simulate this quite nicely.

"OG" wrote in message
...

"a l l y" wrote in message


As well as the location on Earth, it'll depend when you took the photo
during the night (unless you are using an equatorial mount on a tripod).
. If you use Mare Crisium as a guide, this is the upper-right-most feature
on the photo taken on 1/1/2007 and this is on the eastern hemisphere of
the moon, not too far above the moon's equator (about 17 degrees).

The moon rises with its eastern edge appearing first (pointing upwards),
and through the night it rotates clockwise so that when it sets the
eastern edge is downwards. Thus the Mare Crisium will be on the upper side
of the FULL moon in the early evening, at the right hand side of the FULL
moon at midnight and on the lower edge as the FULL moon sets in the
morning. Assuming the camera has the bottom of the frame roughly parallel
to the horizon, the image will appear rotated depending on when it was
taken.

If you check the timing of the photographs you'll see that some of the
images were taken after midnight and others were taken about 6 hours
earlier in the evening. Compare the timing and the orientation and you
should see how the orientation* varies.

Thanks. That makes perfect sense and makes me wonder why I didn't think of
it myself!

ally

"Mike Williams" wrote in message
...
One way to understand what's going on is to imagine that the Moon is glued
to the celestial sphere. As the sky does this:
http://www.robertreeves.com/star_tra...06_9pm-6am.jpg
the Moon goes round with it, changing not only position but orientation.

Of course, it's your camera that's actually revolving, because you've
mounted it on a revolving Earth

Oh, that's a good way of visualising it. Thank you.

ally

In article id,
Dr J R Stockton wrote:

If a crescent Moon is seen in the evening after sunset, it will be
waxing : between New Moon and First Quarter. If it is seen in the
morning before sunrise, waning : between Last Quarter and New Moon.

It may be easier to remember simply that the moon "falls behind" the
sun as it progresses through the month. At new moon, it is in
(roughly) the same place as the sun; a little later - when it is
waxing - it is still in the sky after the sun sets. At the end of the
month - when it's waning - the sun is about to "lap" it, so the moon
rises ahead of the sun in the morning.

-- Richard
--
Please remember to mention me / in tapes you leave behind.

On or about 2009-01-12,
Dr J R Stockton illuminated us with:


To tell from its appearance whether the Moon is waxing or waning,
observe whether it looks more like a "C", with horns to the right, or
like a "D", with horns to the left. Ignore the terminator, the line on
the Moon between light and dark; concentrate on the illuminated part of
the circular edge of the visible Moon. Now remember, firstly, that C is
for Crescendo and D is for Diminuendo; and, secondly, that in the
Northern part of the world, it is in fact the other way round.

The version I remember, not sure where it's from I'm afraid, is: "If
it would make a capital G, it's not Growing, if it would make a
capital D it's not Diminishing"

--
Mark
Real email address |
is mark at | Why does the sun lighten our hair, but darken our skin?
ayliffe dot org |

Mark Ayliffe wrote:

On or about 2009-01-12,
Dr J R Stockton illuminated us with:


To tell from its appearance whether the Moon is waxing or waning,
observe whether it looks more like a "C", with horns to the right, or
like a "D", with horns to the left. Ignore the terminator, the line on
the Moon between light and dark; concentrate on the illuminated part of
the circular edge of the visible Moon. Now remember, firstly, that C is
for Crescendo and D is for Diminuendo; and, secondly, that in the
Northern part of the world, it is in fact the other way round.

The version I remember, not sure where it's from I'm afraid, is: "If
it would make a capital G, it's not Growing, if it would make a
capital D it's not Diminishing"


I learned as a boy that if the moon looked like a "," (that is a comma),
it's "coming" in the meaning 'coming to be full'. If not a comma 'look
alike' it's 'going'. Works in the northern parts of our world.