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> City lights are annoying here, but
> that picture looks like what I grew up seeing.
I have never, ever, in my entire life, seen anything that remotely
approximates this, except on TV and in posters. Every time I see
something like this in films it looks like over the top CG, because real
skies never, ever look like this.
It's quite impressive driving home, actually. By the time you reach
Weedon, you can already tell where MK is because one entire side of the
sky is bright orange. (I have no idea how far it is from Weedon to MK,
but it's surely more than 10 miles.)
If you approach from the south, there's high ground that way. As you
come down the hill, you can see the entire city laid out before you. It
looks utterly huge. It seems to extend from one horizon to the other.
(Obviously an effect of the terrain and it's slope.) And the entire
thing is glowing.
I don't know about you, but when I look up at the orange horizon when
I'm more than 10 miles away, I wonder what the HELL the council's
electricity bill must be, and how much of the light we're paying for is
leaking uselessly into the sky rather than illuminating the streets...
Surely there's some more-efficient way to do this?
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scott wrote:
>> You can also buy telescope tripods that will use a small motor to turn
>> the telescope in counterpoint so the stars appear stationary. I
>> imagine the same would work for a camera, and then it would be the
>> ground that's blury.
>
> That was my point, I know how to keep the stars sharp or to keep the
> ground sharp, but how to get both in the same photo?
Really, really friggin' BIG lenses, as a guess...
Apparently bigger lenses capture more light and generate better images.
Seen any telescopes recently? Big, aren't they? ;-)
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> I'm not sure you'd see a point source. You need enough surface that the
> likelihood of multiple photons reaching your eye in a short interval is
> positive.
If the point source was emitting photons at the same rate as a star though,
I don't think you'd be able to tell the difference between the star and such
a point source.
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Invisible wrote:
> I have never, ever, in my entire life, seen anything that remotely
> approximates this, except on TV and in posters.
Like that line in Madagascar, when they're still in the New York Zoo.
"Oh, look, the star is out!"
"Whoops, nope, just a helicopter."
--
Darren New, San Diego CA, USA (PST)
Human nature dictates that toothpaste tubes spend
much longer being almost empty than almost full.
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Invisible wrote:
> I doubt your eyes can see single photons anyway...
Somewhere between 5 and 10 over the course of 100 ms, for humans.
> Well, the books seem to claim that it *is* caused by waves,
Those books are wrong. It's the same *math* as waves, but it isn't waves.
> babble some nonesense about a "quantum superposition of states" to make
> up for the fact that this explanation makes no sense at all.
It's only nonsense if you don't know what it means.
--
Darren New, San Diego CA, USA (PST)
Human nature dictates that toothpaste tubes spend
much longer being almost empty than almost full.
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>> babble some nonesense about a "quantum superposition of states" to
>> make up for the fact that this explanation makes no sense at all.
>
> It's only nonsense if you don't know what it means.
"And the waves interact to generate these interference patterns."
"OK, so why do I still get the exact same patterns if there's only one
photon there?"
"Um... right, OK... that's because there are these extra versions of the
photon, that all exist at the same time. They generate the interference
pattern. Oh, but you can't measure them, see? Because as soon as you
look at them, they stop existing, right?"
"Dude... WTF?"
--
http://blog.orphi.me.uk/
http://www.zazzle.com/MathematicalOrchid*
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Invisible <voi### [at] dev null> wrote:
> > City lights are annoying here, but
> > that picture looks like what I grew up seeing.
>
> I have never, ever, in my entire life, seen anything that remotely
> approximates this, except on TV and in posters. Every time I see
> something like this in films it looks like over the top CG, because real
> skies never, ever look like this.
Skies look like this in most places in the world (clouds and moon permitting, of
course!), considering how relatively sparse human population centres are. Just
think of all that ocean, too!
You can definitely see skies like this in many locations in the UK. You'll see
good skies within 50 miles of MK. But you do need to make the trip!
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Sabrina Kilian <ski### [at] vtedu> wrote:
> Bill Pragnell wrote:
> > Any expert photographers here want to comment?
>
> Servo motors work wonders, when you can gear them correctly.
>
> There are several tripod heads designed to track correctly against the
> spin of the earth, allowing for long exposures. Anything that works for
> for automatic telescopes can do the same work for a camera.
Yah... as Scott said, if it was done with a tracking mount then it must be a
composite, because both sky and ground are in focus.
I must try some sky photography sometime, though. :)
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scott wrote:
>> You can also buy telescope tripods that will use a small motor to turn
>> the telescope in counterpoint so the stars appear stationary. I
>> imagine the same would work for a camera, and then it would be the
>> ground that's blury.
>
> That was my point, I know how to keep the stars sharp or to keep the
> ground sharp, but how to get both in the same photo?
>
>
With a camera, the trees are going to move relatively little if you are
tracking stars relatively high in the sky. And that little bit they move
will be hidden by the stars that take up the field of view where the
tree was before.
Tracking a star at the horizon would be more difficult. I would have to
think of a good trick there that doesn't involve just cropping or
zooming in on only stars.
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Invisible wrote:
> I doubt your eyes can see single photons anyway...
If the photon hits a rod cell in the eye, then yes. Whether the brain
would process this over the photon flux of your surroundings would be up
for question. In total darkness, I think you would see it.
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