Night Walking

On Wed, 3 Nov 2004 13:35:50 +0000 (UTC), [email hidden] (Chris

Malcolm) said:

The moon rises and sets in (nearly) the same place as the sun.

Not so. I winter, the moon's path mirrors the summer sun's path. Ie.,
it rises in the NE and sets in the NW.

--

Paul

(Watch this space)

Chris Malcolm said:

Phil Cook said:

On Tue, 2 Nov 2004 20:29:40 -0000, Paul Saunders wrote:

Quoted message said:

Quoted message said:

AndyP wrote:

Quoted message said:

Quoted message said:

> Note which side of the hill
> the moon's going to be shining on if there is one.

Quoted message said:

Quoted message said:

It's much like the sun, it rises in the east and sets in the west, it
just does it at different times. Worth familiaring yourself with the
pattern of moonrises and sets.

Quoted message said:

At this time of year in the UK the sun rises somewhat south of east
and sets somewhat to the south of west. The moon rises and sets
opposite the position of the sun's set and rise respectively. So it is
currently rising to the north of east and setting to the north of west
much like the sun does in summer.

In which case how do you explain the phenomenon of the new moon?

The moon rises and sets in (nearly) the same place as the sun. They
both travel within the ecliptic, with the moon having a max deviation
from the sun's track of about 5 degrees.

Damn I thought I had it figured out :-( The position of the moon at
moonrise must be more complicated than I thought.

<fx>grinding noises

The full moon is opposite the sun. So the azimuth of the rising moon
must progress (or is it regress?) from a position co-incident with the
rising sun to a position opposite the setting sun as it waxes from new
to full and back again as it wanes. This will also have an effect on
its elevation at transit, the further north it rises the higher the
maximum elevation.
--
Phil Cook looking north over the park to the "Westminster Gasworks"

Paul said:

On Wed, 3 Nov 2004 13:35:50 +0000 (UTC), [email hidden] (Chris

Malcolm) said:

The moon rises and sets in (nearly) the same place as the sun.

Not so. I winter, the moon's path mirrors the summer sun's path. Ie.,
it rises in the NE and sets in the NW.

That rule is true for the full moon. But it's more complicated than we
thought. See my reply to Chris.
--
Phil Cook looking north over the park to the "Westminster Gasworks"

Phil Cook said:

Paul said:

On Wed, 3 Nov 2004 13:35:50 +0000 (UTC), [email hidden] (Chris

Malcolm) said:

The moon rises and sets in (nearly) the same place as the sun.

Not so. I winter, the moon's path mirrors the summer sun's path. Ie.,
it rises in the NE and sets in the NW.

That rule is true for the full moon. But it's more complicated than we
thought. See my reply to Chris.

Noted, but I'm going by observations, not theory! Maybe I only notice
it when it's full.

--

Paul

(Watch this space)

Paul said:

Phil Cook said:

Paul said:

On Wed, 3 Nov 2004 13:35:50 +0000 (UTC), [email hidden] (Chris
Malcolm) wrote:

>The moon rises and sets in (nearly) the same place as the sun.

Not so. I winter, the moon's path mirrors the summer sun's path. Ie.,
it rises in the NE and sets in the NW.

That rule is true for the full moon. But it's more complicated than we
thought. See my reply to Chris.

Noted, but I'm going by observations, not theory! Maybe I only notice
it when it's full.

See this:

http://curious.astro.cornell.edu/question.php?number=642

--

Paul

(Watch this space)

Paul <[email hidden]> wrote

Quoted message said:

Phil Cook said:

Paul said:

On Wed, 3 Nov 2004 13:35:50 +0000 (UTC), [email hidden] (Chris
Malcolm) wrote:

>The moon rises and sets in (nearly) the same place as the sun.

Not so. I winter, the moon's path mirrors the summer sun's path. Ie.,
it rises in the NE and sets in the NW.

That rule is true for the full moon. But it's more complicated than we
thought. See my reply to Chris.

Noted, but I'm going by observations, not theory! Maybe I only notice
it when it's full.

"Ooowwwwwwwwwwwwwwwwwwwwwwwwwwwwwwllllllllllllll!!!!!!!!!"
--
Gordon

I noticed that Message-ID: <[email hidden]>
from Mike Clark contained the following:

Quoted message said:

As I think has already been pointed out there are genetic differences
that mean that some people have worse night vision than others.

And species differences. My dog has great night vision and can catch
his frisbee at night as easily as in daylight. I just throw then listen
for the 'click' of a clean catch.

It's ok in the park but it would be difficult to take him on a walk in
open countryside unless he was on a lead.
--
Geoff Berrow (put thecat out to email)
It's only Usenet, no one dies.
My opinions, not the committee's, mine.
Simple RFDs http://www.ckdog.co.uk/rfdmaker/

Phil Cook said:

Damn I thought I had it figured out :-( The position of the moon at
moonrise must be more complicated than I thought.

Isn't everything?

Quoted message said:

<fx>grinding noises

The full moon is opposite the sun.

No, it's only opposite when there's an eclipse! We don't get eclipses
every month, so sometimes it's higher than the sun, sometimes lower,
since the orbits don't exactly match. If the orbits happen to cross at
a new moon or full moon, we get an eclipse.

Quoted message said:

So the azimuth of the rising moon
must progress (or is it regress?) from a position co-incident with the
rising sun to a position opposite the setting sun as it waxes from new
to full and back again as it wanes.

Nicely explained by Mr Rooney's link, which was a good basic guide to
the moon's movements, however...

Quoted message said:

This will also have an effect on
its elevation at transit, the further north it rises the higher the
maximum elevation.

Yes, so the moon will nominally reach the highest point in the sky when
the sun is at it's lowest (midwinter) and vice versa.

....but this doesn't allow for variations in the orbital plane, which as
Chris said is no more than 5 degrees. This does mean however that the
height of the moon at transit may be up to +/- 5 degrees different from
what you'd expect if the moon's orbit were in exactly the same plane as
the sun's.

Since I'm at roughly 51.5 degrees north, and the earth's tilt is roughly
23.5 degrees, the maximum height of the sun in the sky here is 62
degrees (90 - 51.5 + 23.5) and the minimum height is 15 degrees (90 -
51.5 -23.5). Presumably therefore the moon could potentially be as high
as 67 degrees or as low as 10 degrees, if I understand this correctly.
This would also affect moonrise and moonset times and azimuths.

Using astronomy software to compare the moon's orbit with the ecliptic
makes this much clearer.

It'll be interesting to compare how the +/-5 degree variations affect
the the new moon to full moon progression. It would be nice if there we
re a simple pattern, a rule of thumb if you like.

Paul
--
http://www.wilderness-wales.co.uk
http://www.wildwales.fsnet.co.uk

Dave Fawthrop said:

Dead easy with a *film* camera, tripod and cable release.

Actually it's a pain in the [censored], especially with reciprocity to screw
things up. And by the time you find out whether your exposures were
correct or not, it's too late to take them again, even if you can
remember what exposures you actually used.

Paul
--
http://www.wilderness-wales.co.uk
http://www.wildwales.fsnet.co.uk

Phil Cook said:

Even easier with a digital camera. Guess the exposure, take a shot,
review the results. If the exposure is wrong adjust and take another.

Exactly, the ideal tool for experimentation, and you don't waste money
experimenting either. And no reciprocity to cause ultra long exposures.

Paul
--
http://www.wilderness-wales.co.uk
http://www.wildwales.fsnet.co.uk

Chris Street said:

What digital camera can cope with a six hour exposure though.....

Most subjects don't need to be exposed for that long, even at night. On
a bright moonlit night, using the moon in the same way you'd use the
sun, relatively short exposures are quite practical.

Paul
--
http://www.wilderness-wales.co.uk
http://www.wildwales.fsnet.co.uk

Paul Saunders said:

Phil Cook said:

Damn I thought I had it figured out :-( The position of the moon at
moonrise must be more complicated than I thought.

Isn't everything?

Quoted message said:

<fx>grinding noises

The full moon is opposite the sun.

No, it's only opposite when there's an eclipse!

Turn off that pedant mode now! When I say opposite I mean roughly.

Quoted message said:

Quoted message said:

This will also have an effect on
its elevation at transit, the further north it rises the higher the
maximum elevation.

Yes, so the moon will nominally reach the highest point in the sky when
the sun is at it's lowest (midwinter) and vice versa.

That only applies to the full moon. Lesser moons will reach a lower
maximum in winter and higher in summer.

Quoted message said:

Using astronomy software to compare the moon's orbit with the ecliptic
makes this much clearer.

Quoted message said:

It would be nice if there we
re a simple pattern, a rule of thumb if you like.

I have a program on my PDA to help me find where it's going to be
rising or setting.

I have an idea go out on the w/e of the next full moon to try some
moonrise sunset shots.
--
Phil Cook looking north over the park to the "Westminster Gasworks"

Phil Cook said:

I have an idea go out on the w/e of the next full moon to try some
moonrise sunset shots.
--

Walking (on topic!) in the evening along a beautiful path through a
clearing in the woods near Silverdale, a few years back, bats flying
around us, swallows not yet gone to roost, I noticed the full moon was
blurred. I mentioned to my kids that my dad had told me that he first
discovered that he needed glasses after seeing 'two moons'. My lad
said, 'I can see two moons!'
'Where?' says I.
He points at the low full moon - 'One there' and turns about and
points at the low sun behind the only cloud in the sky, 'and one
there!'.

--

Paul

(Watch this space)

Paul said:

Phil Cook said:

I have an idea go out on the w/e of the next full moon to try some
moonrise sunset shots.
--

Walking (on topic!) in the evening along a beautiful path through a
clearing in the woods near Silverdale, a few years back, bats flying
around us, swallows not yet gone to roost, I noticed the full moon was
blurred. I mentioned to my kids that my dad had told me that he first
discovered that he needed glasses after seeing 'two moons'. My lad
said, 'I can see two moons!'
'Where?' says I.
He points at the low full moon - 'One there' and turns about and
points at the low sun behind the only cloud in the sky, 'and one
there!'.

Where?

On Wed, 03 Nov 2004 20:55:58 GMT, [email hidden] (Dorian)

Quoted message said:

Paul said:

Phil Cook said:

I have an idea go out on the w/e of the next full moon to try some
moonrise sunset shots.
--

Walking (on topic!) in the evening along a beautiful path through a
clearing in the woods near Silverdale, a few years back, bats flying
around us, swallows not yet gone to roost, I noticed the full moon was
blurred. I mentioned to my kids that my dad had told me that he first
discovered that he needed glasses after seeing 'two moons'. My lad
said, 'I can see two moons!'
'Where?' says I.
He points at the low full moon - 'One there' and turns about and
points at the low sun behind the only cloud in the sky, 'and one
there!'.

Where?

Can't remember offhand.

--

Paul

(Watch this space)

In article <[email hidden]>, u-r-walk@p-t-
cook.freeserve.co.uk says...

Quoted message said:

I have a program on my PDA to help me find where it's going to be
rising or setting.

I just use the one built into my gps.

(see - there's not a thread that can't benefit from a bit of gps-ing)

--
Darren

Paul Saunders <[email hidden]> wrote

Quoted message said:

Chris Street said:

What digital camera can cope with a six hour exposure though.....

Most subjects don't need to be exposed for that long, even at night. On
a bright moonlit night, using the moon in the same way you'd use the
sun, relatively short exposures are quite practical.

You don't need to go out in the dark to get moonlight shots. ;-)
--
Gordon

In article <[email hidden]>, Paul Saunders
<[email hidden]> writes

Quoted message said:

Actually it's a pain in the [censored], especially with reciprocity to screw
things up.

Go on - your dying to tell us. What's reciprocity ?...:-) :-) :-)

DON'T YOU DARE !
--
Bill Grey
http://www.billboy.co.uk

Bitstring <[email hidden]>, from the wonderful
person W. D. Grey <[email hidden]> said

Quoted message said:

In article <[email hidden]>, Paul Saunders
<[email hidden]> writes

Quoted message said:

Actually it's a pain in the [censored], especially with reciprocity to screw
things up.

Go on - your dying to tell us. What's reciprocity ?...:-) :-) :-)

DON'T YOU DARE !

He may not, but I do. It's the problem where doubling the exposure when
the light level haves (which is what you'd normally do) quits working at
very low light levels. You wind up having to quadruple the exposure time
(or worse) instead.

Reciprocity = 1/N (the reciprocal, see) .. except it isn't, at very low
levels, hence reciprocity failure. See, walking is very educational. 8>.

--
GSV Three Minds in a Can
Outgoing Msgs are Turing Tested,and indistinguishable from human typing.

W. D. Grey said:

Go on - your dying to tell us. What's reciprocity ?...:-) :-) :-)

Something we don't have to worry about any more. :-)

Paul
--
http://www.wilderness-wales.co.uk
http://www.wildwales.fsnet.co.uk