31 Dec 08 APOD video: The Sky in Motion

[Indigo_Sunrise]

Am I the only one that cannot see it?

Hopefully it's just a bug that'll get worked out.....



And Happy New Year to all, a little early!

[bystander]

http://apod.nasa.gov/apod/ap081231.html

If you click on the APOD link, This 4-minute, time-lapse video, it will take you to the video.

Happy New Year to all.

[Indigo_Sunrise]

Thanks, bystander. That's what I ended up doing. And it's a very interesting video!
I was just wondering why it had never 'loaded' on my screen. Probably some setting or other.....
Oh well.

*off to ring in the new year*

[bystander]

I'm not sure what setting that would be. It never loaded for me, either.

[Indigo_Sunrise]

That was going to be my next question, to any/everyone: has anybody been able to view the video right from the APOD page itself? Perhaps Mr. Nemiroff or Mr. Bonnell were able to?

[neufer]

That was going to be my next question, to any/everyone: has anybody been able to view the video right from the APOD page itself? Perhaps Mr. Nemiroff or Mr. Bonnell were able to?

It worked OK for me.

It came with a play/pause button at the bottom of the picture and it took a little time to load.
...............................................
I'm assuming the stars flicker because the image is sample compressed.
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For more "flickering stars" see:
http://www.planetary.org/blog/article/00001789/

There used to be a guy who was convinced that such effects as observed with earth pointed cameras were real and meant that earth was constantly bombarded by small meteorites.

[bystander]

It came with a play/pause button at the bottom of the picture and it took a little time to load.

It now works for me, also. It didn't last night or this morning.

I'm assuming the stars flicker because the image is sample compressed.

I assume the stars flicker because of sample compression as well as atmospheric conditions and atmospheric distortion.

[rigelan]

I'll third that. Works fine for me.

[neufer]

I'm assuming the stars flicker because the image is sample compressed.

I assume the stars flicker because of sample compression as well as atmospheric conditions and atmospheric distortion.

They don't flicker in:
http://www.theskyinmotion.com/index.htm ... otion.html

[neufer]

I'm assuming the stars flicker because the image is sample compressed.

I assume the stars flicker because of sample compression as well as atmospheric conditions and atmospheric distortion.

Eyes are small optical detectors sensitive to rapid movement; in contrast, these
particular recording devices here probably do not detect flickering atmospheric distortion.
------------------------------------------------
Why Stars Twinkle
............................................
. Twinkle, twinkle, little bat!
. How I wonder what you're at!
. Up above the world you fly,
. Like a teatray in the sky.
----------------------------------------------

Twinkle Twinkle Little Star
Week of August 23, 1999
http://www.badastronomy.com/bitesize/twinkle.html

<<It's semi-common knowledge that stars twinkle and planets don't. By semi-common, I mean that a lot of folks know that, but I also mean it isn't strictly true.

Stars twinkle because we see them from the bottom of a sea of air. Little cells of air, which are about ten centimeters across and located many kilometers high, move across our vision as we watch the sky. These small bundles of air act like little lenses, bending light as it passes through them. This bending, called refraction, is familiar to anyone who drives on a hot day: hot air just above the road surface bends light more than the cooler air slightly above it. That's why you can sometimes see that shimmery veil of what looks like water on the road; it's really the air bending the light above it. Sometimes you can even see cars reflected in the road!

Anyway, these parcels of air up high in the atmosphere travel to and fro, bending the light from a star in more or less random directions. Stars are big, but they are so far away that they appear to be very small, much smaller to our eyes than each of these air bundles. So when the light gets bent, the apparent movement of the star is larger than the size of the star in the sky, and we see the star shifting around. Our eye can't really detect that motion, because it's too small. What we see is the light from the star flickering. That's why stars twinkle!

So why don't planets twinkle? It's because planets are bigger. Well, really, they're smaller than stars, but they are so much closer they appear bigger to us. They are much bigger in apparent size than the air bundles, so the smearing out of their light is much less relative to the size of the planet itself. Since the image doesn't jump around, they don't appear to twinkle.

There's always an exception though. In very turbulent air, even planets can appear to twinkle. The air is moving so rapidly and so randomly that even something as large as a planet can twinkle.

This effect also plays with a star's color. Blue and green light get bent more than orange and red, so sometimes in very turbulent seeing a star's colors will rapidly change. This usually happens when the star is low on the horizon (so there's more air for it to pass through). The brighter the star, the easier it is to see; Sirius, the brightest nighttime star, is often seen changing from green to red to orange and back, very rapidly. I've seen it myself and it's quite lovely. If you're not prepared for it it's quite surprising; many people report a UFO when they see it! If they're driving, the star appears to follow them too, just like any distant object appears to follow you while you're driving (it's due to parallax). So if a friend says they saw a bright UFO, low to the ground, rapidly changing color and following them gently point out that most likely it wasn't a spaceship, but it was almost certainly extraterrestrial!>>

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. Jules Verne: _Journey to the centre of the earth_
. Chapter 14 "The Real Journey Commences"
[English Hardwigg Translation]
.
<<Presently, after lying quietly for some minutes, I opened my eyes
. and looked upwards [through a vertical 5600 ft volcanic shaft].
. As I did so I made out a brilliant little dot,
. at the extremity of this long, gigantic telescope.
. It was a star WITHOUT SCINTILLATING rays.
. According to my calculation,
. it must be Beta in the constellation of the Little Bear.>>
-------------------------------------------------------------
<<Beta Ursae Minoris (Kochab Arabic الكوكب al-kawkab "the star") is the second brightest star in the bowl of the "Little Dipper," the constellation Ursa Minor. The star is an orange giant and is 126.4 ± 2.5 light years from Earth. It is 130 times more luminous than the Sun. Kochab has a surface temperature of approximately 4,000 K. Kochab and its neighbor Pherkad are sometimes referred to as the "Guardians of the Pole". They served as twin pole stars, Earth's North pole stars, from 1500 B.C. until 500 A.D. Neither star was as proximitous to the pole as Polaris is now.>>
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http://solos.users.netlink.co.uk/solforum.html

<<In 1993 Robert [Bauval] was able to show that the northern
shaft of the Queen's Chamber [of the Great Pyramid] was also
important as it pointed towards a star called Kochab in the Little
Bear constellation. From all of this data we were able to put
forward a convincing case that far from being abandoned,
the Queen's Chamber was used for rebirth rituals and
in particular the "Opening of the Mouth Ceremony".>>
-----------------------------------------------------------------
. James Joyce's _Ulysses_ p. 564
.
What spectacle confronted them when they, first the host, then the
guest, emerged silently, doubly dark, from obscurity by a passage
from the rere of the house into the penumbra of the garden?

The heaventree of stars hung with humid nightblue fruit.

With what meditations did Bloom accompany his demonstration
to his companion of various constellations?

Meditation of evolution increasingly vaster: of the moon invisible in
incipent lunation, approaching perigee: of the infinite lattiginous
scintillating uncondensed milky way, discernible by daylight by an
observer placed at the lower end of a cylindrical vertical shaft 5000 ft
deep sunk from the surface towards the centre of the earth: of Sirius
(alpha in Canis Major) 10 lightyears (57,000,000,000,000 miles) distant
and in volume 900 times the dimension of our planet: of Arcturus: of the
precession of equinoxes: of Orion with belt and sextuple sun theta and
nebula in which 100 of our solar systems could be contained: of moribund
and of nascent new stars such as Nova in 1901: of our system plunging
towards the constellation of Hercules: of the parallax or parallactic
drift of socalled fixed stars, in reality evermoving from immeasurably
remote eons to infinitely remote futures in comparison with which the
years, threescore and ten, of allotted human life formed a parenthesis
of infinitesimal brevity.
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[apodman]

Just to illustrate the variety of experience available in the world today:

The video on the APOD page worked for me, but there was no stop button.

The video on the linked page worked for me, but the sound twinkled.