why is there several distances quoted to the same star. Take Deneb, iv'e seen 1200Ly to 3600Ly.?
553690
The only direct way to measure a star's distance is by its parallax, but the accuracy of parallax get worse that farther away the star is, and at a distance of 1200 or more light years it is pretty bad. Recently the Hipparcos satellite was able to measure the parallax of thousands of stars to a precision never before obtained. You may be seeing distances from earlier measurements and the new Hipparcos data disagree by quite a bit for stars over a hundred or two light years away.
1010059
Farther than they really are? FARTHER?\n\nI just can't imagine the distance that they actually are away. Can you really "see" a dstance of several lightyears? And that is just the distance to our "next neighbours".\n\nIf you can estimate that distance with your bare eye I'll promise you a brilliant career in astrophysics!
16428
If your question is based on what you can see as well as are actually above us and that you are a young person with pupils that will dilate to ~ 7mm tops AND you are observing from a dark dark site with steady seeing conditions (very little "twinkling" of the observed stars)...I think around 15,000 "bright" (we won't get into "limiting magnitude" as that is a large variable) stars is a safe guess. However, technically due to the fact that the as you look towards the constellation Sagittarius in the summer from the N. hemisphere you are looking towards the center of the Milky Way (our galaxy name). That  splash of "cloud" is the combined light of (as C. Sagan would say) "billions and billions" of stars.\nThat latest estimation of our sister galaxy Andromeda is upwards of 300 billion stars alone (it's number of orbiting stars that are influenced and follow it's spin has just recently been upped quite a bit). The current estimate for the Milky Way is 250 billion...however it has also recently been re-classified as a "barred spiral" and no longer a pinwheel shape like "whirlpool spiral". So...who knows a re-estimation of it's star number content may change.\nIn general most galaxies average out to have between 200 - 300 billion stars.\n\nNow...if we take all the assumptions mentioned above (about your eyes, seeing conditions etc) and we add to the number 15,000 of bright individually distinguishable stars in the Milky Way and the number of stars represented by the glow of the Milky Way and the number of stars in the Andromeda galaxy (which a kids good eyes should be able to see ...no sweat) well then the number you can see goes...WAY UP... Carl Sagans answer is an understatement.
117556
didnt you just freaking ask this question like 5 minutes ago??? you can see the same planets in any location, as long as it is dark enough, due to their distance from earth.
16063
If you go out to the desert or a remote area, away from the city & look into the sky on a clear night, you will see many stars & planets in the sky. If you look into the sky using night vision goggles, you will be absolutly amazed to see over a million times the stars & planets in the same sky. You will see so many "Shooting Stars" you wont know which one to watch. With that in mind, knowing that many stars are out there, & thoses are just the ones you can see, the numbers are in favor of YES. Space is just too vast, there are too many other stars & planets (Billions...Trillions, or more) to think that we are the ONLY ones here. Remember, space goes on......forever.... there is no known "end".
329379
Greetings,\n\nYou will sometimes see pictures of stars with points, reference to the link below.  The gentleman who took the picture placed string in a cross-hair pattern over the objective (the opposite end from the eyepiece) to make the points of the stars.  When he was asked why he does this Mr. Russel stated that he just like the way it looked.\n\nThe points on stars in most photographs are generally derived from either slight overexposure or the telescope being out of collimation slightly.\n\n-matt
307862
If you look at the sky on a clear night, away from city lights and polluted air, you'll see a milky band of light right across the sky, the Milky Way, our galaxy.   With a small telescope you'll see the milkiness is made of individual stars.You're looking at the plane of ourgalaxy.   If you look away from this band of light you're looking out into intergalactic space away from the thickness of our galaxy so you don't see so many stars.   If you look in the direction of the constellation Sagittarius, you'll see the Milky Way seems to get wider and brighter.   This is the centre of the galaxy.   So the galaxy is shaped like two dinner plates facing each other, circular, and fatter at the centre than at the edges.   The centre is bright because stars are packed closer together there than way out here.   We know that we're about 30 000 light years from the centre, the diameter of the galawy is about 100 000 light years and the thickness at the centre is about 3000 light years because a particular type of star called a Cepheid variable gets brighter and dimmer with a period that depends on how bright it is.   So we know how bright it really is.   By measuring how bright it appears, we can work out haw far away it is.   So by looking at Cepheids in different parts of the galaxy we can work out its measurements.   And if we look at other galaxies outside our own, many of them are the same shape; fat in the centre, thin at the edges, with spiral arms curving out from the centre, like cloud bands in a hurricane.
857141
Apparent magnitude -- 1.3\nDistance -- 35 light years
777997
I don't know, but I am now very curious as to where this question comes from. I mean, why those particular angles? And what angles are they anyway? Right ascension expressed in degrees instead of hours? Celestial latitude? And why the extreme precision, specified to within 1/10,000 of an arc second?\n\nAnyway, here is a good web site for showing the sky at any time you like. Now all you have to do is try different times until that alignment appears. What a chore!
333277
We've been measureing this quantity for a number of years, and we are getting better results all the time.  The best news is that the different techniques we have been using all agree that the distance is about 26,000 light years.
333419
Dubhe is 124 light years away from us.\nAlkaid is 100\nPhecda is 84\nAlioth is 81\nMegrez is 81\nMerak is 79\nMizar is 78\nDivide by 3.26 to get parsecs.
434313
Mathematically it makes sense based on the number of star systems.\nWe may have been visited throughout human history. Check out the link below...
1048072
There's a relative way to interpret your question as well.  \nWhen you look at the stars, you're seeing them because of the light that travels from them to you.  It takes time for the light to reach you.  So, you're not seeing the stars as they are "now".  You're seeing them as they were in the past.  They may not even be there any longer.  They may have gone nova or even supernova (if big enough), but the information of that event traveling at the speed of light hasn't reached us yet.  Just  remember it's all relative.  So, depeneding on which oberserver you ask and how you define certain terms...just how many stars that you can see are really there?
441685
Thats one of the funniest questions I've ever heard, and definately a first.\n\nRatio...lol \n\nEven if someone could give you an accurate number it would be too large a number on the star side to even begin to comprehend, and too small a number on the freckle side to even be able to comprehend.  No one knows the exact number of stars, or even galaxies that contain them.
203643
The red shift depends on the relative speeds of the source and the detector. It is simply an example of the Doppler shift, which occurs in light whenever there are such differences in velocities.\n\nIt is not true that everything a certain distance away will be moving at the same speed. On top of the expansion of space, there is the peculiar motion of the object itself. So, for example, the Andromeda spiral galaxy is actually moving *closer* to us (i.e. has a blue shift)! The point is that it is close enough that the velocity of expansion is overwhelmed by the particular velocity of that Galaxy. In fact, one of the hard things about estimating Hubble's constant is exactly trying to deal with these peculiar motions.\n\nSo, it is the velocity that determines the red shift, not the distance alone. As you go further out, the velocity of expansion is larger and so the peculiar motions aren't as relevant.
655459
You don't really need the Star's speed, only it's spectral class. The spectral classes are O, B, A, F, G, K and M, with O being the brightest and M the dimmest. If you know how bright the star is intrinsically from it's spectral class, then you can calculate how far away it is from it's apparent brightness in the sky. But this method if fraught with difficulties. Red giants and white dwarfs are off the main sequence of stars. That means that a red star may be much brighter that it's spectral type would indicate and a white dwarf is much dimmer than it's spectral class would indicate. Also, there may be interstellar dust and gas between you and the star that makes it look dimmer that it would through clear space. But if you are careful, all these factors can be taken into account and you can get an approximate distance.\n\nFor the distance to a remote galaxy that is too far away for individual stars to be seen, the red shift of the overall glow of the galaxy can be measured and used to determine the galaxies radial velocity, or the speed at which it is moving away from you. Multiplying that by the Hubble constant gives you an approximate distance.\n\nIf you want a really accurate distance to a star, the only sure way is by measuring it's parallax. But this can only be done for comparatively nearby stars. The Hipparcos satellite measured thousands of stellar parallaxes to a precision not obtainable from the ground, and the catalog is freely available online.
1017333
No, because the speed of light is constant and the distance to stars can be accurately calculated by measuring the time it takes their light to reach us.