Comment by subroutine | Hacker News Reader

Comment by subroutine | Hacker News Reader

For those who swear they have seen a sky with more than 5k stars, next time you're in those same wilderness and staring up at the sky there might be a way to verify whether you are seeing ~4k or ~40k stars.

Here I've compiled a distilled version of the cited tables...

    Mag    Visual_Device         Stars    Example
    -26    naked eye (daylight)      1    Sun
    -13    naked eye (twilight)      1    full Moon
    -06    naked eye (dusk)          1    cres Moon
    -04    naked eye (metro)         2    Venus
    -02    naked eye (metro)         2    Jupiter
    -01    naked eye (metro)         2    Sirius
    +00    naked eye (city)          8    Vega
    +01    naked eye (suburb)       22    Saturn
    +02    naked eye (suburb)       93    Big Dipper
    +05    naked eye (rural)      2822    Jupiter moons
    +06    binocular (rural)      8768    Uranus
    +08    binocular (wild)      77627    Neptune

If you happen to be in a place/time-of-year to see Uranus (n.b. cool mobile apps exist to help locate celestial bodies), you can probably see at least 4k-5k stars. If you can see Neptune with the naked eye, perhaps you are actually seeing 30k-40k stars.

## Notes ##

Each magnitude is 2.5x brighter than the next:

> Mag+01 is 2.5 times brighter than Mag+02

> Mag+01 is 2.5*2.5 times brighter than Mag+03

Mag Scale: http://www.icq.eps.harvard.edu/MagScale.html

Star Count: http://www.stargazing.net/david/constel/howmanystars.html

If you can see Neptune with the naked eye, you're probably a genetically altered mutant with eyes the size of melons.

Neptune is theoretically a naked eye object, barely, against a perfectly black background. In reality the sky isn't perfectly black, even with no man-made light sources. (See e.g. the Zodiacal Light.) So your chances of seeing +08 objects without binos or a telescope are basically zero.

I lived in a very rural area for a while with limited light sources. On a clear night, the sky was absolutely glorious, and going for night time walks under it was a favourite hobby.

But even on the darkest and clearest nights, with half an hour of dark adaptation, +04/5 was as good as the view ever got without binos.

Agreed. I wouldn't expect anyone would be able to spot Neptune. The comment was basically about proving to yourself that you're not seeing more than ~5k stars.

Those of us with cataract removal surgery can see more stars than most as we've lost the majority of our natural UV filter (it makes seeing the Pleiades a LOT easier.)

The one that really floored me was getting moving out to an area that's dark enough to see the milky way without help after ~11pm.

Very few experiences as humbling as stepping outside and seeing it streak across the sky.

Where do you live that you can't see the milky way? I can see it from my inner-city apartment on a clear night.

It might sound like a crazy question, but are you sure you were seeing the milky way? If you have any streetlights at all on your street, there is no way that you can see it with the naked eye (magnitude +5-+6). If you live in the north, it's more likely that you were seeing the aurora.

Our courtyard faces away from the road; so very little streetlight. And all the building lights go off at ~11pm, so there's no local lights around after that.

It's not bright by any means, but yes it's the milky way. (and I live in Melbourne, Australia; not north in any sense :P) It would be very rare to see Aurora Australis from here; I don't anyone that has seen that in this area without driving out of the city and using a long exposure.

Can see the milky way much better when we drive 2 hours out of the city to the family farm.

Can attest to this. Australian cities aren’t as huge as US cities. Not Melbourne, but when I made a trip to central Australia to Uluru. We slept under the stars in the middle of the desert. It was absolutely gorgeous and you could see the Milky Way very clearly. Probably the brightest sky littered with stars I have ever seen.

Driving even 30-60 minutes outside of most Australian cities will get you very dark skies.

But it's still a world of difference to go out somewhere rural, and preferably high up (eg northern NSW Tablelands) to camp under clear skies.

Even without drugs, spending too long staring out at those enormously bright stars can be a very trippy experience.

You can almost convince yourself that at any moment you could fall off the planet and into those stars.

> And all the building lights go off at ~11pm

By German standards, that is not very "inner city". Street lights are on all night, and I cannot see any but the brightest stars even on a clear night. Jupiter and Saturn are easily visible, Orion's belt, too, but Orion's, eh, "sword" is very hard to see. No trace of the Milky Way at any rate.

When I was in a rural area at night for the first time, I was floored to actually see a bright band spreading across the night sky. I had always thought one needs a telescope + CCD to get a view of that.

Most of the rest of us in suburban areas have streetlights that never go off, plus an incredible number of them point the wrong direction (some or most of their output goes straight to the sky, which defeats the point of the lamp) or have been replaced with LED versions that are far brighter than anyone actually needs. I can't say that I've ever seen the milky way outside of photographs.

Pretty much any metro in the US. Up in Seattle we could hardly see any of the planets, never pleiades.

Generally if I can make out 6+ of the stars in pleiades I've got a good shot of seeing the milky way.

At least we can drive pretty easily to dark skies, the East Coast is one big jumble of light pollution.

I don't think that's possible.

Having grown up in the UK, I was amazed when I first saw the Milky Way in New Zealand. I believe it's more visible in the southern hemisphere. [1]

[1] http://darksitefinder.com/how-to-see-the-milky-way/

  > you can probably see at least 4k-5k stars

8768 is the number of stars of magnitude still visible by naked eye across the whole stelar globe. You can see a half of it at the moment, and near the horizon you will not see the fainter stars because the light has to pass much thicker layer of the atmosphere. So about 3000.

FWIW, a not-quite-full moon can be visible in full daylight (late afternoon in summer) even in a major metro area (I've seen it in NYC). The key is that you can only see it if it's separated from the sun by a large angle.

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