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As far as I understand, since the the 12 zodiac constellations (astrological signs) 'surround' the earth, hence it's possible to see by naked eyes a group of 6 astrological signs (only) simultaneously - from one hemisphere.

Assuming it's correct, my question is how many of the 12 zodiac constellations are possible to see in one single night?

Since the earth moving constantly, it seems that the answer depends on the time and season, but assuming that the day and the night are equal in time (March 21th), what will be the answer? To my logic it should be 12 but I am not sure about it.

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  • $\begingroup$ Your question has a significant point of confusion, as "zodiac constellations" and "astrological signs" are completely different things. On the March equinox, astrology says the Sun leaves "Pisces" and enters "Aries", but if a total eclipse occurred that day and you could see the stars near the Sun, you'd find the Sun is nowhere near Aries! The naked-eye star nearest the Sun would be Omega Psc, which is almost a full 30º from the nearest horn of Aries, Beta Ari (RA 01h55m). $\endgroup$ – Chappo Hasn't Forgotten Monica Apr 14 at 1:18
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Running a simulation in Stellarium, on March 21st, you can just about see Pisces at about 7pm, but it is setting, and at 5am Aquarius is just rising, before being hidden by the sun. The sun is "in Pisces" on the 21st (the astrological houses have not been updated) but it is a pretty big constellation!

This means that you can see, or partly see all the zodiac constellations. Although Pisces and Aquarius are not fully visible, but you can see the other 10 at some point during the night.

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    $\begingroup$ You can't see any astrological signs. They are not visible in the sky at all. You can see the constellations of the zodiac, but that is a quite different thing. Some of the constellations are quite a lot bigger than others, and they aren't evenly spaced. And of course if you include the Snake Handler it makes 13 $\endgroup$ – James K Apr 6 at 23:22
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    $\begingroup$ Its probably worth noting that some of the zodicac constellations are rather small and dim. None of them is as impressive as Orion. $\endgroup$ – James K Apr 6 at 23:24
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    $\begingroup$ @UbiquitousStudent terminology is indeed important : "astrological sign" is about astrology, which this website either doesn't care about or actively opposes, "constellations of the zodiac" is about astronomy. You're welcome here, as long as you talk about stars, history or observation, with falsifiable claims. At least that's the way I understand it. $\endgroup$ – Eric Duminil Apr 7 at 4:26
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    $\begingroup$ @JamesK Scorpius is pretty impressive and can perfectly match Orion's might. Orion reigns in the winter nights, but come summer nothing can rival Scorpius spanning more than a handbreadth along the horizon (certainly not Orion, as he's nowhere to be seen, ha!). Saggitarius next to Scorpius in the warm summer nights is one of my favorite views. $\endgroup$ – walen Apr 7 at 6:47
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    $\begingroup$ @walen may I ask at which latitude you live? I've been lucky enough to see the southern sky a few years ago. Scorpio is dim and low from where I live, and having seen it on all its beauty painfully reminds me that I only see a small part of it now. (49°N for me, BTW) $\endgroup$ – Eric Duminil Apr 7 at 6:54
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Depends on you considered as "see an astrological sign", because the constellations are pretty big and are not always on top of the elliptic or in their 30º spot of it. Scorpius for example is a bit off the ecliptic, so a general calculation on the visibility of the ecliptic might tell you that you see the right longitude (210º), but (most of) Scorpio could be under the horizon.

Another way to state you question, so that is more tractable from an astronomic point of view, is "how many degrees of the ecliptic could I see during a given night at my location"? And the answer is about 300º, meaning that the sun will block about 60º, because it is physically there, against the stellar background and you cannot see through it.

So, you will never be able to see the full 360º at night (the twelve signs) , but, if the night is long enough at your location, you might be able to see up to 300º.

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  • $\begingroup$ Thank you. 1. I've been told in past that the sun blocks one constellation (30 degrees). Is it wrong? 2. Is it possible to see more than 6 astrological signs simultaneously from a landscape view? $\endgroup$ – Reckless Glacier Apr 6 at 21:33
  • $\begingroup$ The 60° is more about the sunlight blocking the view from the night sky, twilight, refraction and all. During a sun eclipse, for example, the sun will not block 60° of the sky. It was meant in the context of your question. And in a perfect location, at any one time, you might get to see up to 180° of the ecliptic (30° for each constellation if you still want to know how many could fit). $\endgroup$ – Eduardo Trápani Apr 6 at 21:48
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You don't clarify whether you must see the whole constellation or perhaps seeing any star of the constellation suffices.

Right now, 07 April 2020, 14:58:21 UTC, at $65^{\mathrm{o}} 38' 55.14'' \mathrm{S}$ $34^{\mathrm{o}} 3' 14.60'' \mathrm{E}$ at least one star from each zodiacal constellation except Aries is barely above the horizon (assuming an idealized spherical Earth and cooperating weather).

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  • $\begingroup$ Is there any reason why you chose this particular location, which, as far as I can tell, is pretty close to Antarctica? $\endgroup$ – Eric Duminil Apr 7 at 15:24
  • $\begingroup$ @EricDuminil : It approximately puts the ecliptic on the horizon. There are other locations that do so. $\endgroup$ – Eric Towers Apr 7 at 15:31
  • $\begingroup$ I'm asking about whole zodiacal constellation. $\endgroup$ – Reckless Glacier Apr 7 at 16:36

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