<p>What is the period of unique horoscopes? In other words how long does it take before any configuration of the classical planets repeats?</p>

<p>The seven classical "wandering stars" are: Sun, Moon, Saturn, Jupiter, Mars, Venus, and Mercury.</p>

<p>Assume a horoscope is created by dividing the ecliptic into 12 equal regions and then for a particular day noting which region each of the 7 "wandering stars" is occupying relative to the earth. For example, a horoscope could be: Sun in Aries, Moon in Capricorn, Saturn in Taurus, Jupiter in Libra, Mars in Pisces, Venus in Aries, Mercury in Aries.</p>

<p>Since Saturn revolves around the sun once every 29 earth years, Jupiter every 12 years, and Mars 1.88 or so, multiplying together we have 654. So, relative to each, they would seem to repeat their configuration every 654 years.</p>

<p>This is potentially a complicated question which might require a simulation to determine the answer. For example, today (5 December 2016), the following is true for the tropical zodiac:</p>

<p>Sun in Sagittarius<br>
Moon in Aquarius<br>
Mercury in Capricorn<br>
Venus in Capricorn<br>
Mars in Aquarius<br>
Jupiter in Libra<br>
Saturn in Sagittarius<br></p>

<p>So, one instance of this problem would be to determine the next date at which this same configuration will next recur.</p>

CC BY-SA 3.0
2016-12-05T15:12:42.067Z
Least Common Multiple Calculator: http://www.calculatorsoup.com/calculators/math/lcm.php  You'll have to convert the orbital periods from years to something, like seconds, where all the planets orbit in an integer number of units, then convert back when you're done with the calculation.
Wayfaring Stranger
CC BY-SA 3.0
2016-12-05T20:37:54.780Z
@barrycarter Maybe you could describe the process you used as an answer?
Tyler Durden
CC BY-SA 3.0
2016-12-05T21:21:10.120Z
Comments are not for extended discussion; this conversation has been [moved to chat](http://chat.stackexchange.com/rooms/49625/discussion-on-question-by-tyler-durden-period-of-unique-horoscopes).
called2voyage
CC BY-SA 3.0
2016-12-13T22:43:20.787Z
I'm voting to close this question as off-topic because it's about the pseudo-science of astrology
adrianmcmenamin
CC BY-SA 3.0
2016-12-14T15:48:48.830Z
@adrianmcmenamin Please consider discussing whether or not this question should be closed on meta. This question approached closure before and the close votes were retracted after some discussion. Note that there is one comment claiming the question is on-topic with two upvotes. Also, note that questions that are astrology-only with no value to the modern science of astronomy *are* already deemed off topic, so if you create a meta post, ask about this specific case and not astrology in general. We don't want to start a close/reopen war.
called2voyage
CC BY-SA 4.0
2020-12-08T11:55:43.827Z
I’m voting to close this question because astrology != astronomy
peterh
CC BY-SA 4.0
2020-12-08T18:21:49.033Z
@peterh-ReinstateMonica - as discussed in previous years, this question is entirely about astronomy. The terms may be couched in astrology, but this is a purely astronomical question.
Rory Alsop
CC BY-SA 4.0
2020-12-18T03:32:43.097Z
I'm voting to leave this question open. The knee-jerk reaction to anything that suggests an interest in astrology is a disappointingly non-scientific approach. Would a question about whether lead can turn into gold through supernova nucleosynthesis be closed because it smacks of alchemy? Let's base our decision on the *fact* that the question is about a genuine astronomical issue, rather than on the *assumption* that the OP might have a non-scientific interest or motivation.
Chappo Hasn't Forgotten
CC BY-SA 4.0
2024-09-22T00:52:18.023Z
The ratio between any two planets' periods is irrational, so is a meaningful answer possible?
Anton Sherwood
<solar-system>
Period of unique horoscopes?
Tyler Durden
# Period of unique horoscopes?

(Asked by: username_0 on 2016-12-05)

What is the period of unique horoscopes? In other words how long does it take before any configuration of the classical planets repeats?

The seven classical "wandering stars" are: Sun, Moon, Saturn, Jupiter, Mars, Venus, and Mercury.

Assume a horoscope is created by dividing the ecliptic into 12 equal regions and then for a particular day noting which region each of the 7 "wandering stars" is occupying relative to the earth. For example, a horoscope could be: Sun in Aries, Moon in Capricorn, Saturn in Taurus, Jupiter in Libra, Mars in Pisces, Venus in Aries, Mercury in Aries.

Since Saturn revolves around the sun once every 29 earth years, Jupiter every 12 years, and Mars 1.88 or so, multiplying together we have 654. So, relative to each, they would seem to repeat their configuration every 654 years.

This is potentially a complicated question which might require a simulation to determine the answer. For example, today (5 December 2016), the following is true for the tropical zodiac:

Sun in Sagittarius  
Moon in Aquarius  
Mercury in Capricorn  
Venus in Capricorn  
Mars in Aquarius  
Jupiter in Libra  
Saturn in Sagittarius

So, one instance of this problem would be to determine the next date at which this same configuration will next recur.

**Tags:** solar-system
> **Comments:**
> **username_1**: Least Common Multiple Calculator: http://www.calculatorsoup.com/calculators/math/lcm.php  You'll have to convert the orbital periods from years to something, like seconds, where all the planets orbit in an integer number of units, then convert back when you're done with the calculation.  
> **username_0**: @barrycarter Maybe you could describe the process you used as an answer?  
> **username_2**: Comments are not for extended discussion; this conversation has been [moved to chat](http://chat.stackexchange.com/rooms/49625/discussion-on-question-by-tyler-durden-period-of-unique-horoscopes).  
> **username_3**: I'm voting to close this question as off-topic because it's about the pseudo-science of astrology  
> **username_2**: @adrianmcmenamin Please consider discussing whether or not this question should be closed on meta. This question approached closure before and the close votes were retracted after some discussion. Note that there is one comment claiming the question is on-topic with two upvotes. Also, note that questions that are astrology-only with no value to the modern science of astronomy *are* already deemed off topic, so if you create a meta post, ask about this specific case and not astrology in general. We don't want to start a close/reopen war.  
> **username_4**: I’m voting to close this question because astrology != astronomy  
> **username_5**: @peterh-ReinstateMonica - as discussed in previous years, this question is entirely about astronomy. The terms may be couched in astrology, but this is a purely astronomical question.  
> **username_6**: I'm voting to leave this question open. The knee-jerk reaction to anything that suggests an interest in astrology is a disappointingly non-scientific approach. Would a question about whether lead can turn into gold through supernova nucleosynthesis be closed because it smacks of alchemy? Let's base our decision on the *fact* that the question is about a genuine astronomical issue, rather than on the *assumption* that the OP might have a non-scientific interest or motivation.  
> **username_7**: The ratio between any two planets' periods is irrational, so is a meaningful answer possible?  

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