What is night sky: Definition and 38 Discussions

The night sky is the nighttime appearance of celestial objects like stars, planets, and the Moon, which are visible in a clear sky between sunset and sunrise, when the Sun is below the horizon.
Natural light sources in a night sky include moonlight, starlight, and airglow, depending on location and timing. Aurorae light up the skies above the polar circles. Occasionally, a large coronal mass ejection from the Sun or simply high levels of solar wind may extend the phenomenon toward the Equator.The night sky and studies of it have a historical place in both ancient and modern cultures. In the past, for instance, farmers have used the status of the night sky as a calendar to determine when to plant crops. Many cultures have drawn constellations between stars in the sky, using them in association with legends and mythology about their deities.
The anciently developed belief of astrology is generally based on the belief that relationships between heavenly bodies influence or convey information about events on Earth. The scientific study of celestial objects visible at night takes place in the science of observational astronomy.
The visibility of celestial objects in the night sky is affected by light pollution. The presence of the Moon in the night sky has historically hindered astronomical observation by increasing the amount of ambient brightness. With the advent of artificial light sources, however, light pollution has been a growing problem for viewing the night sky. Optical filters and modifications to light fixtures can help to alleviate this problem, but for optimal views, both professional and amateur astronomers seek locations far from urban skyglow.

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  1. S

    B Night Sky of Alpha Centauri: Sol as a Bright Star

    I finally got around to watching the movie "Avatar", which takes place in the Alpha Centauri system. I was thinking that a great little scene between the 2 main characters (i.e., the paraplegic Earthling and the Centauri woman) would have been looking up at the night sky and seeing Sol as a...
  2. Kwantumnaut

    I A busy and interesting night sky in Mackinaw City

    Hello there, first let me say I hope this is the right section for this topic, and if not please feel free to move it! So a couple days ago I took a trip up to Mackinaw City, Michigan, and saw a few interesting and intriguing things (luckily!) in the sky that night, and was just hoping maybe...
  3. E

    Night sky cooling, cooling by transmission or as 'heat sink'

    Howdy all. Regarding the phenomenon of radiative night sky cooling, where an object (such as a blackbody) on the surface of the planet cools via radiating energy into space: can the cooling be ascribed to the transmittance of the radiation through the atmosphere (as such a clearer night with...
  4. Meruem

    B What is the black that we see in the night sky?

    Summary: Can black means many thing? The black we see in night sky has to mean many things First of all, from point of views of human eyes then the photons can't reach our eyes so it appears black. Secondly, the objects appear smaller as we go farther from that object. So, at some point object...
  5. M

    Stargazing Mysterious Phenomenon Seen in the Night Sky

    There is supposed to be a meteor shower tonight, so I was looking up at the sky, and saw something that at first I thought could be one, but it moved too slowly, so I watched as it danced in a zig zag across the sky, as high as a star, appearing as a star, yet floating slowly enough through the...
  6. P

    B Can someone please identify what I saw? (lights in the night sky)

    I'm the farthest thing in the world from an expert, but I've seen the usual number of pictures and Discovery Channel programs... and I never saw anything like I saw last night (8-1): I'm in San Diego, California. I went outside Tuesday night a little bit after 11 PM, and was casually looking...
  7. J

    Is the Sun's Movement Different in the Southern Night Sky?

    hi. i am from sydney australia. over the xmas holidays i spent some time in tasmania, and had a very memorable night sleeping on a 1300m high mountain with 360° veiws and crystal clear night. i stayed awake all night hoping to see the southern lights but no luck. however i did see something else...
  8. sophiecentaur

    Stargazing The Pleiades: an underrated glory of the night sky

    I was doing my usual untargeted tour of the sky last night and checking the objects I'm now familiar with when I saw a new twinkle down on the NE horizon. The binoculars made it look interesting so I looked at it with my telescope. What a fantastic fairyland of light. No wonder the Pleiades are...
  9. Janus

    Insights How Representative is the Night Sky? - Comments

    Janus submitted a new PF Insights post How Representative is the Night Sky? Continue reading the Original PF Insights Post.
  10. wolf1728

    I Are almost all stars in the night sky brighter than the Sun?

    I was thinking about adding another page to my website concerning the nearest stars, the brightest stars, etc. In a list of the nearest stars, the vast majority are brighter than the Sun. (I looked for stars with an absolute magnitude that was greater than the Sun's (4.85) and had a visual...
  11. sami_m

    The probable trajectory of the ninth planet in night sky?

    What would be the propable trajectory and position of the ninth planet that has been suggested few days ago (20.1.2016 by Konstantin Batygin and Michael E. Brown) ? if i understood correctly, the exact position of the planet is unknown and has not been evaluated. But by looking this article...
  12. T

    Baffled by observation -- 3 lights in the night sky

    Hi! :) This is my first message here. The reason I joined this forum is because there are some knowledgeable people here who might be able to shed some light on an observation that I cannot explain. It happened during the night of July 28, 2013, at around midnight, and it still keeps me...
  13. Yadama

    Mom's New Camera Captures the Night Sky!

    Well today my mother got a pretty nice camera, she's been wanting one for a while and what better way to test it then getting some shots of the moon! This is the best photo she could get, the rest were very shaky and we're probably going to invest in a tripod. I also went out with my cheapy...
  14. Ritzycat

    Exploring the Night Sky with a Telescope in Central USA

    I've had a telescope for a few years. I know pretty basic stuff - and I can easily find planets when they are in the sky (mostly because I know Venus is around sunrise/sunset, and Jupiter & Saturn are non-twinkling bright objects in the sky). I know a few constellations - Cassiopeia, Orion, Ursa...
  15. E

    How much of the night sky one could see from various locations

    I was wondering about how much of the night sky one could see from various locations on the Earth. At anyone time, near sea level, how much is visible? My guess is that much less than half is visible, with the rest being blocked from view by the earth. Is that correct? How small a portion...
  16. Government$

    Night sky and supernova questions

    Here are my two questions: 1) When i look up to a night sky, do i see mostly stars and galaxy's rather then planets? Here is my logic: Since star is many many times more brighter then reflected light of planets i see brightest object and since we are looking form Earth planets and stars...
  17. B

    Stargazing Viewing night sky in the middle of a major city

    Wouldn't do me any good. I live in the middle of a major city, and, the last time I looked at the night sky at my true local astronomical midnight, it looked like God had turned out the lights.
  18. N

    Mysterious Night Sky Object - Help?

    Mysterious Night Sky Object - Help!? Well, I've commented on others' questions on a number of occasions, but something just occurred which has thrown me for a loop, and I could really use an opinion or two. I've been into amateur astronomy for 43 years, and have seen any number of very...
  19. C

    The night sky - Venus (noob Q)

    Venus' synodic period is 583.92 days. Does that mean that Venus is 583.92/2 days the evening star and 583.92/2 days the morning star (with some period in between when it's probably to close to the sun to be visible)? What I want to know is some kind of formula so that I know where and when to...
  20. S

    What *would* the night sky look like if we could see the entire EM spectrum?

    Assuming, of course, that we simply rescaled our color perspectives so that longest wavelengths = red, shortest wavelengths = violet. Are there any such pictures?
  21. I

    Interested in looking at the night sky

    Hey guys. I want to get started in looking at the night sky from my roof etc etc. I was thinking of getting Celestron SkyMaster Giant 15x70 Binoculars with a tripod as a starting tool which is only about $70-80. I don't want to buy a $4,000 telescope without knowing what I'm looking for lol...
  22. 1

    What's Out There? The Emotions of Stargazing

    When I look into space, I can't make it out, but I am looking at so much. It depresses me to that I may never know what's out there, that all of the questions I have may never be answered. Does anyone else feel this way?
  23. M

    New 3D model of solar system and night sky

    Hi, for all of you we´ve made new user-friendly interactive 3D model of solar system and night sky with real-time planet´s positions. http://www.solarsystemscope.com/ (requires flash) Application in a simple way helps students and laymen to understand the movements of the planets and...
  24. P

    Exploring the Night Sky with a Small Telescope in Missouri

    So I just got my dads old telescope out, cleaned it, and installed new motors and cleaned the primary and secondary mirrors, and it's ready for use! It's a reflector with a 4-3/8" primary mirror, and I wonder: what can I see with this thing (besides the moon, obviously)? I know this is a super...
  25. T

    How can I tell if the night sky is observable from here?

    Firstly, sorry if this is a stupid question but I was just wondering if there's a way I can tell if the night sky is observable where I'm living, Dubai. I really want to get a telescope but it'll be a waste if I can't even use it here. Where I live, I wouldn't say that there's too much...
  26. J

    Explore the Night Sky with Google Sky

    http://www.google.com/sky/#latitude=-11.802834233547672&longitude=20.91796875&zoom=6&Spitzer=0.00&ChandraXO=0.00&Galex=0.00&IRAS=0.00&WMAP=0.00&Cassini=0.00&slide=2&mI=1&oI=0" as the title indicates what is that thing near moon?
  27. S

    Are those shooting stars or satellites in the night sky?

    One summer night in 2005 I was out on my roof with a couple of my friends, and the sky was perfectly clear. We could see thousands of stars, it was amazing. We were in the countryside far away from any city lights. Well, the entire night we were just star gazing and every 5 minutes we...
  28. glondor

    Mystery Lights Seen in Night Sky: What Are They?

    Do you think this is an effect of the night scopes? or is there some other phenominon going on here. I give the video 100% credability, as it seems several observers see the same thing... what are they seeing. Seems the brightest is over the biggest city.
  29. B

    Night Sky Cooler: Can Hot Water Cool?

    I have a basic question regarding black body cooling. Suppose a person at sea level on a clear night, were to use a hot water solar panel which is a good black body, and contain it in a box in a vacuum with a 'window' that was very good at transmission of long wave ir 'looking' only at the sky...
  30. wolram

    UK's Night Sky: Is It Becoming Clearer?

    The night sky in my area does seem clearer of late, even with the multi giga watt street/road lights shining bright many stars can be seen, is this true across the uk?
  31. C

    Constellations in the Night Sky

    Im living in India, and I've just got a telescope, what constellations could I see? And how do I go about checking them out?
  32. M

    Exploring the Night Sky: Learn about Constellations

    I want to learn about the night sky and the data about constilation so when I look at the sky I could figure out which star belongs to (x) constilation and its relative position with others... Is there any link which can help me out? Thanks for your help
  33. A

    Glimpsing a Mysterious Whizzing Object in the Night Sky

    i saw summin last night it whoosshed past, i was just looking out the window at the stars it was a really clear night and then i saw it i don't kno what it was a comet? or a rock or something falling to earth. but it made me feel better, i was feeling upset before. around quarter to 9.
  34. turbo

    Average luminosity of night sky vs frequency

    Average luminosity of night sky vs frequency... What is the average luminosity of the night sky in all observable wavelengths, from the shortest down to the longest? Are there estimations/approximations anywhere of average luminosity plotted against wavelength? Are there links to papers that...
  35. S

    Night Sky Watching: The International Space Station

    I woke up at 4:30 PST (San Diego) and couldn't go back to sleep so I decided to take my telescope out and finally check out Saturn, the Orion Nebula, and Mars again. They looked awesome through the 8" telescope and I wish I was able to take pictures. Then around 5:30 I saw a really bright object...
  36. A

    Strange sight in the night sky

    Not quite sure where this post should go so I'm putting it here. My wife and I were walking the dog the other night and looking toward scorpio we saw a flash of light and then a very broad "vapor trail" like a glowing stripe crossed upwards across the sky. We walked on further and about five...
  37. S

    What's there to see in the night sky at this time of year?

    Saturn sets before it gets dark and Jupiter right after. I've already seen the cluster in Hercules and the Andromeda galaxy. What else can I look for? Light pollution in my area is moderate, but nothing horrible. I'm using an 8" Meade Starfinder. Thanks!