Skip to main content

Questions tagged [naked-eye]

Questions about observations performed without the aid of any optical instrument.

Filter by
Sorted by
Tagged with
3 votes
0 answers
83 views

Low Latitude Aurora

It's been in the news recently that the aurora was visible in Europe at much lower latitudes than usual, ie, not just in Scandinavia but as far south as the Adriatic. Sadly, I didn't find out about it ...
ScienceSnake's user avatar
  • 1,048
1 vote
1 answer
112 views

Ancient adjudication of the new moon from witness testimony

The ancient method of certifying the new moon in the Land of Israel in ancient times is described in Mishnah Rosh Hashanah 2:6. Witnesses would come to Jerusalem and testify before the Sanhedrin that ...
wberry's user avatar
  • 349
4 votes
2 answers
203 views

Are there naked eye binary stars with periods less than 100,000 years?

An optical double is two stars which appear very close together because they chance to be lined up as seen from Earth but are actually tens, hundreds or thousands of light years apart in space. A real ...
M. A. Golding's user avatar
1 vote
1 answer
233 views

How close can Venus be to the sun in the sky and still be visible to the naked eye?

Assuming no artificial light, what is the minimum number of degrees apart would the sun and Venus have to be during the beginning of civilian twilight for the planet to be visible to the naked eye to ...
Bob516's user avatar
  • 1,489
2 votes
0 answers
901 views

What does it look like to view an annular solar eclipse with the naked eye?

How does the experience of an annular solar eclipse compare to a total solar eclipse? In particular, what does it look like to take a glimpse of an annular solar eclipse with the naked eye? How dark ...
Jack Daus's user avatar
6 votes
2 answers
428 views

A what distance could we see the Sun?

How far away can we see the Sun with the naked eye? How far with an amateur telescope? And with the James Webb telescope? In my own calculations the Sun would appear magnitude 6 at 56 ly, magnitude 8 (...
HugoF's user avatar
  • 186
7 votes
1 answer
2k views

Is Uranus the farthest object in Solar System that you can see with naked eyes?

The following text is from this article: The fact is, even at its brightest, Uranus is still quite faint. It’s barely perceptible as a dim speck of light to the unaided eye, even under dark skies. At ...
Nilay Ghosh's user avatar
  • 4,733
1 vote
2 answers
369 views

How many planets can be seen by the naked eye? [closed]

I can see Venus and Mars, what about the others?
abc's user avatar
  • 145
3 votes
1 answer
113 views

What objects in the night sky have the narrowest range of visible light

What objects visible to the naked eye at night have the narrowest spectrum of visible light reaching the earth. Put another way, Which objects are most visible as a specific color or colors rather ...
Schquestoning's user avatar
1 vote
0 answers
77 views

How do stellar magnitude and integrated magnitudes compare, perceptually?

(P.S. this is naked eyed) Magnitudes are easily defined for point-like objects i.e. stars. However, for extended objects, the "magnitudes" quoted are actually integrated magnitudes. For ...
Cheng's user avatar
  • 342
7 votes
0 answers
166 views

Angular resolution of naked eye at night; type of vision used

It appears that most sources quote the angular resolution of the eye as 1', regardless of day and night. For instance, Naked eye Seconds of Arc and the Unaided Eye However, the following websites give ...
Cheng's user avatar
  • 342
4 votes
0 answers
70 views

If you could get up close to them, what nebulae would be the most visually impressive to your naked eye?

Pop cult sci-fi movies like to show nebulae as they appear in photographs, but to a live, real-time viewer: these dazzling, snazzy and amazing backdrops to spaceship flying in front of them in real-...
The_Sympathizer's user avatar
2 votes
2 answers
242 views

What would be the highest possible naked-eye apparent magnitude?

What would be the highest possible magnitude $m$ of some star that could be viewed with a naked-eye? I am acquainted with this question, but mine is about the ideal conditions. In order to achieve ...
User123's user avatar
  • 2,879
3 votes
2 answers
325 views

Back when the CMB was predominantly in the visible spectrum, would it have been visible to the naked eye?

The CMB is a near-perfect black-body spectrum, and assuming this has been true since the de-coupling, we should have been able to see the glow. In fact, at a certain point, it should have been almost ...
zucculent's user avatar
  • 1,758
6 votes
2 answers
507 views

Can Jupiter's rings be seen with the naked eye by an astronaut nearby? How difficult would it be?

Maybe a basic question, apologies. I understand that there would be different answers depending on how far is "nearby", depending on how inclined our orbit is, and what is our alignment with ...
we'll see's user avatar
  • 325
5 votes
2 answers
268 views

Can Mercury be seen from the 60th parallel north on Earth? Shetland, Faroe, Norway, St Petersburg, Alaska

I'm originally from a city in Spain which is 40 degrees north, and I used to watch Mercury (naked eye and telescope) every time I had the opportunity, that is, when Mercury was at maximum elongation ...
we'll see's user avatar
  • 325
6 votes
2 answers
387 views

What percentage of meteors are visible to the naked eye?

I read on a box of Lucky Charms that there are nearly a million shooting stars every day. My initial reaction was, "that's obviously false." However, upon further research I discovered that &...
T Hummus's user avatar
  • 163
1 vote
0 answers
45 views

What magnitude stars are visible during a quarter moon, during nautical twilight?

Assuming I'm looking for stars at least 50° from the quarter moon, is there any way to determine what magnitude stars would be visible to the naked eye, in a sky without light pollution, during ...
Bob516's user avatar
  • 1,489
13 votes
1 answer
689 views

Will Asteroid (2021 LD6) be visible to the naked eye?

There's a lot of hoopla online about asteroid 2021 LD6's close approach to Earth. Will be close enough and large enough to be seen with the naked eye? PS: More on the object: MPC or JPL
Rob Adams's user avatar
  • 133
3 votes
1 answer
327 views

Is it safe to look at an annular eclipse during sunrise? [duplicate]

I'm lucky enough to be where an annular eclipse will happen at the same time as sunrise. Usually, it's dangerous to look at an eclipse directly. However, the sun appears much less bright at sunrise. ...
Half's user avatar
  • 41
1 vote
1 answer
66 views

Is it easier to see the young moon when it's closer to the sun?

With the naked eye, would it be easier to see the moon when it's close to the sun, because it might reflect some more light (or not, I'm not sure) or farther from the sun because the sun shines ...
mesrefoglu's user avatar
5 votes
1 answer
368 views

Naked-eye limiting magnitude: mismatch between Wikipedia, online converter and Shaefer's formula

I'm trying to make sense of the difference between the reference Sky Quality Meter (SQM) readings given in the Wikipedia article on Bortle scale, online converters like [1] that are based on Shaefer's ...
Ruslan's user avatar
  • 967
35 votes
3 answers
6k views

Can Pluto be seen with the naked eye from Neptune when Pluto and Neptune are closest?

When Neptune and Pluto are closest, about 100 million mi (160 million km) from each other, would an observer on Neptune (or rather on one of its moons, since Neptune is gaseous) be able to see Pluto, ...
Plutos Loyer's user avatar
4 votes
3 answers
437 views

Starlight: are the rays that we see here on Earth parallel?

Are the rays of light emitted from stars that are perceived by an eye here on Earth parallel? Do they travel in a straight line from the star to the eye, never crossing, and equidistant? Do they ...
user avatar
3 votes
1 answer
131 views

Would a naked eye supernova become a disc in a matter of days?

Stars are points of light even in telescopes- if they go supernova, their diameter does expand, but given the distance of even nearby stars, they would still be points of light, I suppose? I am asking ...
yippy_yay's user avatar
  • 275
5 votes
2 answers
3k views

Two luminous points disappearing in the sky

I saw a few days ago two luminous points in the sky, which were quite close (about 1-2 degree of separation between them) and not apparently moving (or to slow to be noticed with the naked eye). The ...
Lexi Jones's user avatar
14 votes
3 answers
33k views

Will just a glimpse (less than a second) of sun during partial solar eclipse damage eyes?

This question arose when I thought that on Normal Days, at least I have observed bright sun while going outside, going to office, in park etc. for less than a second. It happens almost daily. Not ...
Vikas's user avatar
  • 341
1 vote
0 answers
97 views

When and why was zero right ascension defined to be at the vernal equinox?

When (and why) was zero right ascension defined to be at the vernal equinox? Who established or defined this standard?
pr1268's user avatar
  • 183
3 votes
3 answers
113 views

Can we see asteroid 1998 OR2 with unaided eye?

Will I be able to see the asteroid 1998 OR2 with the naked eye on April 29? If so, where can I find more information on when and where I'll be able to see it?
rbhat's user avatar
  • 401
9 votes
1 answer
584 views

Will the nebula of Betelgeuse be visible to the naked eye? How bright, how large, how soon, for how long?

When Betelgeuse goes core collapse supernova it will leave a supernova remnant. Will it become visible to the naked eye? If so, in what time frame will it be visible. Will it be star like from the ...
LocalFluff's user avatar
  • 11.4k
3 votes
0 answers
61 views

Would Martian sunrise/sunset look the same at the Thaumasia Plateau as the rovers' photographs?

If observing the sunrise or sunset, with the naked eye, from the Thaumasia Plateau (app. 260°, -10°), 6 kilometers above Mars elevation zero, would it have the same blue hue as the images of the ...
Bob516's user avatar
  • 1,489
7 votes
2 answers
240 views

Are meteors visible on Mars?

If a person were standing on the surface of Mars, under ideal viewing conditions for seeing a meteor: no clouds, the sun has long set, would a meteor be visible to the naked eye considering how thin ...
Bob516's user avatar
  • 1,489
2 votes
1 answer
149 views

Seeing a star near zenith around sunset

I'm recalling while taking a university astronomy class the professor brought a few of us up to the observatory, around sunset. He showed us a star near zenith with the telescope. After we left the ...
Bob516's user avatar
  • 1,489
5 votes
1 answer
246 views

What is the apparent magnitude of the faintest stars visible during a full moon?

Assuming the viewer is far from any light pollution, it is a cloudless night, and humidity is very low. What is the faintest apparent magnitude of stars visible to the naked eye during a full moon (...
Bob516's user avatar
  • 1,489
6 votes
1 answer
266 views

Assuming no light pollution, was "2C. 1406" ever visible to the naked eye?

Joseph Needham, in his Science and Civilisation in China Vol. III, claimed that there was an ancient record of a nova about three thousand years ago. As a result of private correspondences with a "Dr ...
dROOOze's user avatar
  • 163
0 votes
1 answer
70 views

Lunar eclipse above the atmosphere

Would a lunar eclipse seen from low (or even high) Earth orbit look different to the naked eye than it does from the surface of the Earth? The only image I could find taken from orbit was the photo ...
Bob516's user avatar
  • 1,489
3 votes
1 answer
323 views

Could Ganymede's aurora be seen with the naked eye?

If one was orbiting in the Jovian system, as depicted in this artist conception, could the aurora be seen unassisted? Hubblesite-Illustration Credit: NASA, ESA, and G. Bacon (STScI)
Bob516's user avatar
  • 1,489
2 votes
2 answers
208 views

Would the solar corona be visible from the distance of the outer planets?

If the photosphere was blocked, before the sun rises on an airless moon in the outer solar system, would either the inner or outer corona be visible to the naked eye?
Bob516's user avatar
  • 1,489
2 votes
2 answers
1k views

What fraction of starlight, seen from Earth, is actually reflected light?

Thanks to reflected starlight, many planets and comets in the Solar System have been visible to humans since long before the development of modern astronomy. Some of the starlight from outside the ...
StarlightDown's user avatar
2 votes
2 answers
212 views

What is "class 4 light pollution" and could I estimate my own area's class visually?

This question currently asks I am living in the northern hemisphere in Greece and in class 4 area (light pollution scale).Is it possible to see the Andromeda galaxy with a naked eye? I'd never ...
uhoh's user avatar
  • 30.7k
5 votes
2 answers
2k views

Is it possible to view the Andromeda galaxy with the naked eye in Greece?

I am living in the northern hemisphere in Greece and in class 4 area (light pollution scale). Is it possible to see the Andromeda galaxy with a naked eye?
Jmk's user avatar
  • 51
3 votes
3 answers
759 views

Why is the color of the moon so similar to the clouds?

Why the moon looks like the cloud-structure on the blue sky among the clouds?
Przemek Zubowicz's user avatar
33 votes
2 answers
15k views

Did I see Pluto with my naked eye?

Early this morning going out on the balcony, I looked up on a star chart app to verify it was Jupiter I was seeing. Then I noticed the alignment of Mars, Saturn, and Pluto on the app. Never being able ...
Jason P Sallinger's user avatar
6 votes
2 answers
840 views

Mars night sky -- Phobos and Deimos?

I'm having a debate about how bright Martian nights would be, in terms of both the sky itself and ground illumination. This answer seems to indicate that the stars would be only dimly visible, and ...
Skatche's user avatar
  • 163
85 votes
2 answers
19k views

Could the dinosaurs have seen the asteroid that killed them?

Wikipedia says the Chicxulub impactor is thought to have been a 10-15 km diameter object. Would it have been visible to a (human*) naked eye before impact? And if so, would it have appeared like a ...
Robert's user avatar
  • 955
1 vote
3 answers
283 views

Will we be able to see our galaxy if we travel far enough?

Will we be able to see our galaxy if we travel far enough? When we leave earth far enough, we'll be able to see Earth from distant, is it same with the galaxy? if we travel far enough, will we see the ...
Abhiyan Sapkota's user avatar
29 votes
2 answers
28k views

Why is it okay to watch a sunset but not an eclipse?

People watch sunsets all the time. You don't see people using special "sunset glasses". Yet with an eclipse, warnings are posted everywhere not to view it without special glasses. Why is this?
End Antisemitic Hate's user avatar
4 votes
2 answers
5k views

Is it safe to view a solar eclipse with eyeglasses along with eclipse glasses?

In an article on Ars Technica about safely viewing a solar eclipse, they say this: First, what not to do: Don’t view the eclipse with your naked eye or unfiltered telescopes, binoculars, sunglasses ...
Thunderforge's user avatar
0 votes
1 answer
113 views

What was this red deep sky object? [closed]

I was looking through sky yesterday and saw something red in sky (naked eye ) like nebula or something then tried using stellarium and mobile observatory apps to find out what it was, But couldnt find ...
Nemexia's user avatar
  • 101
1 vote
1 answer
159 views

Why isn't our local interstellar space colorised?

Looking at answers to this question, people seem pretty convinced that human naked eye should be able to see the colour of ionised gas/dust cloud when they are inside an emission nebula. And we know ...
bitinn's user avatar
  • 111