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How you can calculate your Rising Sign (Ascendant)!

WHAT IS THE RISING SIGN

The Rising Sign as the name suggest is defined in astrology as the constellation emerging at east on the horizon at the moment of birth. According to astrology the ascendant is very important in the characterization of an individual and this explains the interest that there has always been around its calculation. In literature and on the internet there is a lot of material about the ascendant, as a starting point you can look at wikipedia:

http://http://en.wikipedia.org/wiki/Ascendant

If you are not interested to the computation way of ascendant but you only want to know yours, you can do it here:

HOW YOU CAN CALCULATE THE RISING SIGN

Often can arise the curiosity to know how to calculate the ascendant, looking on the internet there are several sites that explain how to do it but for one reason or another I have not found any site that explains it in full details and so I decided to write this little tutorial using same case explained step by step.

THE SIDERAL TIME

The purpose of ascendant calculation it's to find the 'Sidereal Time' of the own birth, the sidereal time or 'stars's time' is defined as the time the earth needs to make one complete rotation around the stars and so it's useful to determine where are the stars in a given time, so knowing this figure at the time of the birth of a person it's possible 'to see' which are the rising costellation at east. For further information about sideral time you can look at:

BASIC INFORMATION TO COMPUTE THE RISING SIGN

We can start doing the 'shopping list', in other words look at which are the data we need to cumpute the ascendant calculation, do not be afraid because we will see together how to find most of the necessary informations:

2) There was summer time?

3) Latitude and longitude of the place of birth

4) The Time Zone

5) The tables with the constellations positions or 'houses table'

Ok! Let's start with an analysis of those data:

we need to know latitude and longitude for our calculation because the appearance of the sky changes moving from one point to another and from one hemisphere of the globe to the opposite.

Today know the latitude and longitude of a place is much easier than in the past ... and we have several options:

-use gps antennas, the ones used for navigation systems ... often the navigation software has the ability to display latitude and longitude of the current position

-use google maps ... by default google maps does not give us this information, however, there is a little trick that allows us to obtain it: look for the place that interests you, go to maximum zoom level and centered it on the screen, then copy this command into the address bar (where you just say 'http://maps.google.com/'):

a small window with the valuable information of latitude and longitude will appear.

-use sites that use google maps and automate the research for latitude and longitude as example the excellent:

-use data available on-line. For my site I have gathered the full details of all the Italian country and the coordinates of the major city in the world ... excellent starting points if you decide to follow this way are these sites:

for my site I had to build a database with the timezone of the main cities of the world, even here in web fortunately there is help ... I can suggest you these links:

one last thing about latitude and longitude remember that these quantities are expressed in degrees and minutes (sixtieth of a degree) we'll re-find this information below

you can see that the tables are shown only for latitudes greater than zero and thus for the north hemisphere, if we want to calculate the ascendant for someone born in the sud hemisphere it's enough to consider the table associated with the latitude without the minus sign and the reverse the results.

For my site, of course, I had to store all those informations.

Now that we know something more about ascendant we can move on to real calculation... without wasting time let's start with an example step by step and let's analyze the details of the calculation.

A) EXAMPLE OF CALCULATION OF RISING SIGN FOR HEMISPHERE NORTH - LONGITUDE EAST

SIDERAL TIME = 697

SIDERAL TIME = 697-60=637

SIDERAL TIME = 637-60=577

a calendar year, from the viewpoint of the sidereal time, is divided into 24 hours which means that each day corresponds about 24 * 60/365 = 3.94520547945 minutes and then try to spread these minutes in a single day and see how much correction should be made for Pluto ... it just a simple proportion:

1440:3.94520547945 = 697: x

where 1440 are the minutes in a day (24 * 60) while 697 are the minutes between midnight at the time of the birth of Pluto (the first value we have calculated)

let's solve our proportion and see that x is:

x = (3.94520547945 * 697) / 1440 = 1.90958904

we can approximate our value to 2 minutes and then we can update our sidereal time:

SIDERAL TIME = 577+2=579

where 396 are the 6 hours and 36 minutes of the first of January converted to minutes (6 * 60 +36) in this case we can make a small approximation ... then we can update our sidereal time:

SIDERAL TIME = 579+1110=1689

Pluto was born in Rome, which has longitude 12:29 EAST and latitude 41.54 NORTH; moving towards east time grows, then increase the time considering a correction factor: (need to emphasize a fact, the coordinates are expressed sixtieth of a degree so in order to calculate we could transform the sixtieth in cents but the error is minimal and acceptable for our purposes)

SIDERAL TIME = 1689+4*12.29=1738.16=1738

1738 minutes are more than the minutes in a day which are 1440 (60 * 24) so we have to make a 'module 1440' operation in our case this means simply subtract 1440 minutes:

SIDERAL TIME = 1738-1440=298

transform our sidel time in hours and minutes:

SIDERAL TIME = 4h58m

let's get the tables that are closest to our latitude of birth, in the case of Pluto this one is 41.54N therefore we can take the tables for latitude 40 degrees north, then let's scroll the data until we find the line that interests us:

S.TIME | M.C. | XI | XII | ASCEND | II | III |

... | ... | ... | ... | ... | ... | ... |

04h56m | 15GE16 | 14CN44 | 15LE42 | 17VI14 | 17LI42 | 16SC43 |

05h00m | 16GE11 | 15CN37 | 16LE32 | 18VI01 | 18LI32 | 17SC37 |

05h04m | 17GE07 | 16CN31 | 17LE21 | 18VI49 | 19LI23 | 18SC31 |

... | ... | ... | ... | ... | ... | ... |

17VI14

which means that Pluto has a rising sign in Virgo (Virgin) positioned at 1714'

B) EXAMPLE OF CALCULATION OF RISING SIGN FOR HEMISPHERE SOUTH - LONGITUDE WEST

this time we can go faster:

SIDERAL TIME=23*60+47=1427

SIDERAL TIME=1427

SIDERAL TIME = 1427+300=1727

1440:3.94520547945 = 1427: x

x = (3.94520547945 * 1427) / 1440 = 3.909589 = approximately 4 minutes

SIDERAL TIME=1727+4=1731

3.94520547945 * 396 +35 = 534.82 = 534

SIDERAL TIME=1731+534=2265

SIDERAL TIME = 2265-4*77=1957

SIDERAL TIME = 1957+(12*60)=2677

SIDERAL TIME Mod 1440 = 2677 Mod 1440= 1237 =20h37m

remember that Lima has latitude 12 south and then we can use, with good approximation, the tables of the houses on the latitude 10 North, so take the section that join our data:

S.TIME | M.C. | XI | XII | ASCEND | II | III |

... | ... | ... | ... | ... | ... | ... |

20h32m | 05AQ38 | 04PI56 | 08AR53 | 13TA19 | 13GE23 | 09CN39 |

20h36m | 06AQ37 | 06PI01 | 10AR02 | 14TA23 | 14GE20 | 10CN34 |

20h40m | 07AQ35 | 07PI08 | 11AR12 | 15TA27 | 15GE17 | 11CN29 |

... | ... | ... | ... | ... | ... | ... |

I hope the explanation is clear and simple, and if you liked it, pleas link this site on your blog or your sites! :)