Sky at night.

[dww]

What I would like to know is, when I look at the sky, the plough (great bear big dipper etc), when it is above my head it takes up about one tenth of the sky, horizon to horizon. But when it moves round to the north, the same star cluster now takes up three quarters of the sky (horizon to horizon), and when it comes back above me it is back to its normal size again, cannot think why. Can anybody explain why this happens?.

[shorty82]

I'm no astronomy expert but I'm thinking probably some kind of magnification effect of the atmosphere or something along those lines.

[Guest]

The same effect as the sun or moon looking larger in the mornings and evenings Al

[Stilettoscot]

Refraction of the atmoshpere on the horizons...

[Bubba136]

What I would like to know is, when I look at the sky, the plough (great bear big dipper etc), when it is above my head it takes up about one tenth of the sky, horizon to horizon. But when it moves round to the north, the same star cluster now takes up three quarters of the sky (horizon to horizon), and when it comes back above me it is back to its normal size again, cannot think why. Can anybody explain why this happens?.

The differences in the sizes of the constellation can be attributed to:

1) the time you enter the pub.

2) the time you go outside and take your first wizz

3) the time you leave the pub to go home

(simple formula: The size of the constellation is directly proportional to the amount of liquid intake at your favorite pub times the intensity of the buzz from the liquid. ) :lmao:

[jmc]

I'm no astronomy expert but I'm thinking probably some kind of magnification effect of the atmosphere or something along those lines.

That's exactly what's going on.

The same effect as the sun or moon looking larger in the mornings and evenings

Al

Right on that point too.

Refraction of the atmosphere on the horizons...

Yes, caused by the curvature of the Earth and its atmosphere. The air, as it is wrapped around the Earth, acts like a giant magnifying glass when whatever you are looking at is low on the horizon.

[thedesigner]

The differences in the sizes of the constellation can be attributed to:

1) the time you enter the pub.

2) the time you go outside and take your first wizz

3) the time you leave the pub to go home

(simple formula: The size of the constellation is directly proportional to the amount of liquid intake at your favorite pub times the intensity of the buzz from the liquid. )

especially if you fall over on the way home, then the stars will be right in front of your eyes....

[radiodave]

Sorry to disappoint, but there's no magnification or atmospheric effect going on. It's an illusion. We perceive it as bigger, and it's all psychological. Don't believe me? Use your finger, index card, or something you can sight the moon with to figure the diameter. Then compare it when it's up high or down low. Same size, trust me! There's plenty of info on the "moon illusion". Here's one good article I found.

http://www.lhup.edu/~dsimanek/3d/moonillu.htm

[roniheels]

The differences in the sizes of the constellation can be attributed to:

1) the time you enter the pub.

2) the time you go outside and take your first wizz

3) the time you leave the pub to go home

(simple formula: The size of the constellation is directly proportional to the amount of liquid intake at your favorite pub times the intensity of the buzz from the liquid. )

especially if you fall over on the way home, then the stars will be right in front of your eyes....

Now these are the scientific explanations that I understand.

[Guy N. Heels]

Sorry to disappoint, but there's no magnification or atmospheric effect going on. It's an illusion. We perceive it as bigger, and it's all psychological. Don't believe me? Use your finger, index card, or something you can sight the moon with to figure the diameter. Then compare it when it's up high or down low. Same size, trust me! There's plenty of info on the "moon illusion". Here's one good article I found.

http://www.lhup.edu/~dsimanek/3d/moonillu.htm

Thanks for that useful post, Radiodave. I can distinctly recall one night when my family and I were driving home and the Big Dipper was right out in front of me. Indeed, it seemed to fill up my entire windshield (windscreen for you Brits). I mean this was absolutely the most spectacular thing I had ever seen in the night sky, or so I thought. Well I was finally overcome with it and so I stopped my van so that the entire family could get out and stretch their legs and take a look at this thing. Trouble was that after we all dismounted and took a good look directly at the night sky, well things suddenly didn't seem to be quite what I first saw through the windshield. The Big Dipper was still right where it should have been, but gazing at it directly made it seem much smaller. So go figure.

[traceyloveshoes]

I'm very much into astronomy and I can't say that I noticed the big dipper (URSA Major) get any bigger or smaller. Somtimes on it's side or upside down but I've never noticed much difference in the size but hey I'm not the most observant of people. Side note if you look at Orion then the star top left of the constellation is called beetleguese and it has an orange glow. This is because it is one of the most massive stars that we have found, a red giant, and it is expected to go supernova in the not too distant future (in the scheme of things). Also if you look at the star in the middle of of what would be Orions sword, this is not actually a star but the Andromeda Galaxy our closest neighbour and also it's on a collision course with the Milky Way. Just some info I thought you might find intersesting! =)

[yozz]

Hate to disappoint you, but the Andromeda galaxy is in the Andromeda constellation. It is a rather vague spot that really doesn't mimic a star. The nebula you refer to is the Orion nebula, which isn't a galaxy but an enormous gas cloud inside our own galaxy. There are many pretty pictures of it, but they are all taken with big telescopes. With a little amateur telescope you can just see a vague spot. Ursa major, of which the big dipper is part, is really a large constellation. The big dipper is just the tail part. It is in its best position when indeed it is low, when the bear is with its feet down. Y.

[traceyloveshoes]

It appears that astronmy sucks worse than my spelling thanks yozz!

[HappyFeat]

The basic reason is the Earth's rotation. Objects appear larger when close to the horizon (rising and setting.) Its very similar to why the sun and moon appear larger when near the horizon, but less pronounced when higher in the sky. As mentioned above, Ursa Major is a large constellation that is very near the pole star, Polaris. Polaris is the center of rotation for the entire night sky and is at the tip of the handle of the asterism the little dipper. The two front stars of the ladle of the Big Dipper point toward it and the Big Dipper rotates around it. When the Big Dipper rises, it will be near the horizon and appear large. But as the evening progresses, the Earth rotates and the Big Dipper rises higher in the sky, this appaering smaller. One of my favorite bits of trivia about the Big Dipper is that the "star" in the next to last star in the handle is actually five stars. Because of the great distance they epear as one star to the naked eye. You can see them easily with a small telecsope. On a side note, I hope everybody was able to look at the full moon the last couple of nights. It is the closest the moon has been to the earth during its full phase in 15 years...

[Guy N. Heels]

The basic reason is the Earth's rotation. Objects appear larger when close to the horizon (rising and setting.) Its very similar to why the sun and moon appear larger when near the horizon, but less pronounced when higher in the sky.

As mentioned above, Ursa Major is a large constellation that is very near the pole star, Polaris. Polaris is the center of rotation for the entire night sky and is at the tip of the handle of the asterism the little dipper. The two front stars of the ladle of the Big Dipper point toward it and the Big Dipper rotates around it. When the Big Dipper rises, it will be near the horizon and appear large. But as the evening progresses, the Earth rotates and the Big Dipper rises higher in the sky, this appaering smaller.

One of my favorite bits of trivia about the Big Dipper is that the "star" in the next to last star in the handle is actually five stars. Because of the great distance they epear as one star to the naked eye. You can see them easily with a small telecsope.

On a side note, I hope everybody was able to look at the full moon the last couple of nights. It is the closest the moon has been to the earth during its full phase in 15 years...

One more bit of trivia - actually minutia - due to a phenomonon called precession the "pole star", which at the moment is Polaris, actually changes every thousand years or so, and in time to come Polaris will no longer be our "pole star". However, it is precisely this same tiny bit of wobble that cause our "pole star" to shift that also causes the stars to wobble a tiny bit in relation to Polaris. So while our stars seem to rotate around Polaris - they really do not. The true center of rotation is off just a tiny bit.

To the average person all of this discussion has no meaning whatsoever. It's only when you consider us as "Spaceship Earth" that you begin to realize that we're actually going somewhere and therefore we need precise navigational tools like atomic clocks to help tell us what's going on.

[Bubba136]

It's only when you consider us as "Spaceship Earth" that you begin to realize that we're actually going somewhere and therefore we need precise navigational tools like atomic clocks to help tell us what's going on.

As if we can do anything about it.

(like a colony of aunts living on a giant log that's floating down the big river with the aunts believing they're in charge! )

[HappyFeat]

One more bit of trivia - actually minutia - due to a phenomonon called precession the "pole star", which at the moment is Polaris, actually changes every thousand years or so, and in time to come Polaris will no longer be our "pole star". However, it is precisely this same tiny bit of wobble that cause our "pole star" to shift that also causes the stars to wobble a tiny bit in relation to Polaris. So while our stars seem to rotate around Polaris - they really do not. The true center of rotation is off just a tiny bit.

To the average person all of this discussion has no meaning whatsoever. It's only when you consider us as "Spaceship Earth" that you begin to realize that we're actually going somewhere and therefore we need precise navigational tools like atomic clocks to help tell us what's going on.

That reminds me of another bit of trivia...that we are in constant motion in many different ways...

1) The movement of the tectonic plates

2) The rotation of the earth around the sun

3) The earth revolving on its axis

4) The pression of the Earth's axis

5) The solar system revolving around the core of the Milky Way

6) The outward expansion of the universe

If you ever feel like you are being pulled in too many directions...its because you are...but remember time and movement stop in only one place in the known universe- the line at the DMV.

[Guy N. Heels]

That reminds me of another bit of trivia...that we are in constant motion in many different ways...

If you ever feel like you are being pulled in too many directions...its because you are...but remember time and movement stop in only one place in the known universe- the line at the DMV.

WRONG! Obviously, you've never seen Washington, DC rush hour traffic. Why do they call it rush hour???

[Stilettoscot]

GNH, Yes, I have seen it, and it's almost half as bad as Boston's. At least DC has a grid-like street design...Boston?? Not so much...LOL

[HappyFeat]

WRONG! Obviously, you've never seen Washington, DC rush hour traffic. Why do they call it rush hour???

You got me there! I have seen it...almost as slow as the legislative process in DC. That's why I have a Metro card...

GNH,

Yes, I have seen it, and it's almost half as bad as Boston's. At least DC has a grid-like street design...Boston?? Not so much...LOL

As for Boston, anything that's called the "Big Dig" frightens me a little...

Interestingly I just heard an interesting bit of trivia and would love for any astronomy buffs to comment...On a clear night there are only about 2,000 stars visible to the naked eye...would love to know if that's accurate.

[dww]

All I say is Tom Tom, but what has this to do with the sky at night.

[yozz]

Interestingly I just heard an interesting bit of trivia and would love for any astronomy buffs to comment...On a clear night there are only about 2,000 stars visible to the naked eye...would love to know if that's accurate.

This depends on a few factors.

1: where you are (city, mountains)

2: whether there is a full moon.

3: how good your eyes are.

Under ideal conditions for all three cases the number may be more than 5000.

In the center of NY you should be pleased with a few dozen.

When it is really dark and it is overhead you can see the milkyway as a band

across the sky. That is very impressive. I have seen this only once as I am

a city person (with a few good star atlasses though).

Y.

[Bubba136]

Speaking of things astronomical: Has anyone else come across the article in the AmericanThinker.com about the loss of daylight in the northern hemisphere? Someone wrote a "Letter to the Editor" that really adds some food for thought:

"Dear editor: "I don't know if anyone else has noticed, but I have detected a new crisis that I have named 'the daylight change crisis.' I first noticed it sometime around the end of June this year. I started paying attention and created computer models and sure enough I was right! We are losing daylight at an astonishing rate. Each day we are losing approximately 2 minutes of daylight and my computer models predict total darkness by next July. I have been able to detect this phenomenon around the entire Northern Hemisphere. And here is the scary part: the day light appears to be leaking to the Southern Hemisphere. I thought I should bring it to the attention of great scientists like Al Gore so he can help solve this new crisis."

As we didn't already have enough to worry about:w00t2:

[jmc]

Speaking of things astronomical: Has anyone else come across the article in the AmericanThinker.com about the loss of daylight in the northern hemisphere? Someone wrote a "Letter to the Editor" that really adds some food for thought:

"Dear editor: "I don't know if anyone else has noticed, but I have detected a new crisis that I have named 'the daylight change crisis.' I first noticed it sometime around the end of June this year. I started paying attention and created computer models and sure enough I was right! We are losing daylight at an astonishing rate. Each day we are losing approximately 2 minutes of daylight and my computer models predict total darkness by next July. I have been able to detect this phenomenon around the entire Northern Hemisphere. And here is the scary part: the day light appears to be leaking to the Southern Hemisphere. I thought I should bring it to the attention of great scientists like Al Gore so he can help solve this new crisis."

As we didn't already have enough to worry about:w00t2:

Some completely anecdotal historical references seem to indicate that this has happened before, once or twice (or maybe thousands of times, the records are a little sketchy). There seems to be a cyclical phenomemon involved, with a period of roughly 365.25 days. Some disputed texts actually mention a gain in daylight hours, apparently only during certain times of the year. More research is clearly needed -- perhaps a Federal grant?

[HappyFeat]

My first question is how does his computer model work? Flawed methodologies lead to flawed results.

[Stilettoscot]

Everyone knows that phenominon is due to all the cows farting in KY, IN, and IL (not to mention eastern IA). Their farts are giving the Planet a "fever" as Mr Gore would say. Duh.

[Guy N. Heels]

Some completely anecdotal historical references seem to indicate that this has happened before, once or twice (or maybe thousands of times, the records are a little sketchy). There seems to be a cyclical phenomemon involved, with a period of roughly 365.25 days. Some disputed texts actually mention a gain in daylight hours, apparently only during certain times of the year. More research is clearly needed -- perhaps a Federal grant?

Absolutely! We need a federal grant that will fund the construction of an observation platform, either on or near Jupiter so that we can study this phenomenon and develop a course of action; or at least some recommendations. But who would sponsor such a bill?

[jmc]

My first question is how does his computer model work? Flawed methodologies lead to flawed results.

Hmmmm, seems I recall the computer science people had a saying to that effect.

Oh yeah, "Garbage In, Garbage Out".

That goes back at least to the Fortran days, if not before!

[Guy N. Heels]

Hmmmm, seems I recall the computer science people had a saying to that effect.

Oh yeah, "Garbage In, Garbage Out".

That goes back at least to the Fortran days, if not before!

Wasn't that an operation like RAFB? The command was GIGO and what you got out... Oh shucks, you get the picture.

[thedesigner]

I remember the time when I saw the stars really clearly. It was a long time ago, when the fair came to town, a cold and frosty night. The moon was full and shining, the stars were glowing, the constellation was glittering back at me. There I was, singing Starman to myself... I was so busy looking at the big dipper, I walked straight into a lamp post. The stars all came out that night....