How can you tell the difference between a planet and a star in the night sky?

Answer 1

Stars "flicker" while planets reflect a solid 'dot'

Answer 2

The bright ones are most likely planets. Except for Sirius - that's a star. How do you find Sirius? It's really easy. You find what looks to be the brightest star in the sky and see if you can see a big triangle of stars below it. That's Canis Major (the Big Dog) and Sirius is the dog's head, which is why Sirius is also known as the "Dog Star." So, once you've eliminated Sirius, it's easy.

First off, without a telescope you can only see Venus, Mars, Jupiter, and Saturn. Venus is the brightest object you'll see in the early evening or morning sky. Jupiter is the next brightest planet. Jupiter is very white-blue in color and pretty bright. Saturn is harder to spot, it's only really obvious on a dark night away from city lights. You can tell it's Saturn by its yellowish color. Mars at its closet point with Earth is brighter than Saturn and it is obviously orange-red in color.

So, to summarize, just look for the brightest objects in the sky, keeping in mind you could be looking at Sirius and thinking it's Venus, but once you see that same bright star with the same stars under it, you know it can't be Venus. Venus moves. Sirius is so far away, you'd need a 1000 years to see it shift just a little bit in the sky. If you see something even brighter than Sirius, you've found Venus, the brightest thing in the night sky (except for the moon, of course).

Answer 3

The general rule of thumb is that planets don't twinkle. But that is not strictly true in all cases and can't be depended on.

Sometimes you cannot tell just by looking, unless you know your constellations well enough to notice a 'star' out of place. The idea that planets do not twinkle is mostly a myth. Years of direct experience proves this.

Planets can also twinkle like stars.

As a general rule is that the brighter planets, like Mercury to Saturn do not twinkle - much.

But they can twinkle if the atmosphere is warm or windy or the planet is viewed at a low angle near the horizon. I have personally witnessed Mercury, Venus and Jupiter twinkle violently on some summer evenings, regardless of their brilliance. In the telescope, their images had heat waves rippling around the edges. To the naked eye, this appears as twinkling like a star.

The twinkling is cause by atmospheric turbulence and heat waves in the air. In the winter months in cold climates, this effect is much reduced.

In a good telescope, the major planets usually appear as distinct disks of some discernable size rather than an infinitely tiny twinkling point. The exceptions may be things like Pluto, small asteroids or other very distant bodies.

 

Answer 4

Early astronomers were able to tell the difference between planets and stars because planets in our Solar System appear to move in complicated paths across the sky, but stars don't.

That is, if you observe the sky night after night, the stars will all appear in fixed positions with respect to each other. They will rise and set a few minutes earlier each night (an effect that is due to the Earth's motion around the Sun), but otherwise nothing will change. This is why the background stars are sometimes referred to as the "celestial sphere" -- from our point of view, it looks like the stars are "painted" onto a gigantic sphere that surrounds Earth and therefore are unable to move with respect to each other.

Planets, on the other hand, are observed to move in very complicated paths with respect to the background stars, sometimes even appearing to go "against the grain" and reverse their directions. Therefore, they are easily distinguishable from stars if you look at the sky night after night. Although ancient astronomers did not have a correct explanation for this phenomenon, we now know that the complicated motion is just a projection effect -- it is due to the fact that Earth and the other planets are physically moving in orbits around the Sun, so the planets' relative positions as seen from Earth (with respect to the fixed background stars) change as time goes on.

Answer 5

Twinkling or not is an uncertain way to distinguish them -- if the planet is not bright, it may well twinkle. The better way is to put your telecope drive motor to sidereal speed. If you are looking at a star, the image will not move; if it's a planet, it will. Or take the coordinates and use a star chart. I did that once -- saw an object, one evening, that I thought was an aircraft, but it did not move; too far away, I supposed. Next night, saw it again in the same place, so it couldn't be an aircraft, nowhere near the ecliptic, so it couldn't be a planet. I eyeballed angles to it from Polaris and Cassiopeia, and was able to identify it on a star chart.

Answer 6

For Mars, Jupiter and Saturn you can form a "pinhole camera" using your fingers (or poke a hole in a card) hold it close up to your eye and you can see the "disk" of the planet. A star still looks like a point that twinkles. This takes a little practice like on Jupiter when you know it's Jupiter, but I use it quite often.

Another trick (in Northern Hemisphere) is to find Arcturus (one of the brightest stars, third) by following the "arc" of the big dippers handle. If the "star" in question is brighter (or nearly as bright) it's a planet (unless it's been demoted or is Sirius or Canopus).

Answer 7

True, planets don't twinkle. They also follow the celestial equator. With only a few exceptions they tend to be brighter than most stars

Planets are seen high in the East or West and almost overhead most of the time and they easily show their color. Saturn is veyr yellow, Jupiter Yellow White, Mars Reddish, Venus blue white and brighter than anything else except the moon and sun.

Answer 8

Planets don't twinkle, they will also be found along a line we call the ecliptic. This is the line through the sky that all the planets, moon, and sun follow across the sky. This line connects all the Zodiac constilations.

Answer 9

I believe that the way to tell the difference is to look at them and see if the color sparkles or stays constant. A star will sparkle and a planet will not.

Or get a Telescope!

Answer 10

u can't see any planet by your eyes from the earth at night because they don't have enough light.

but there is only one planet which is near earth and i don't remeber its name which u can see it by your eyes. the other things observed in sky are stars