Problem calculating Ascendant using the suggested formula

Discussion:

(too old to reply)

Arpit Tambi

2008-09-21 12:58:43 UTC

Hi all

I am a new member to this group. I found this group while searching
the math of astrology.

Basically my curiosity to know 'how astrology works' took me here. I
am trying to calculate a simple birth chart so that I can understand
what happens in the background.

I've been able to successfully calculate the MidHeaven(MC) but am
totally clueless to the Ascendant calculations.

I'm interested in calculating the birth chart for a person born
midnight GMT, 6 December 1970. So the following details are obtained -

Local Sidereal Time - 4 hours 57 min
RAMC = 74.25
Inclination = 23.44
Latitude at GMT = 51.5

MC = 74.68 (Hence Gemini)

how to calculate Ascendant?
I tried this formula (read this in the great article An Astrological
House Formulary by Michael P. Munkasey and the same formula has been
used in Astrolog Software)

ASC = ARCCOT (- ( (TAN f x SIN e) + (SIN RAMC x COS e) ) ÷ COS RAMC)

its not possible to get ARCCOT directly in MS Excel, also all values
have to be in Radians not degrees so I used following instead -

temp = - ( (TAN f x SIN e) + (SIN RAMC x COS e) ) ÷ COS RAMC
ASC(in radians) = ARCTAN(1/temp)

Here, f = latitude = 0.898844565 (in radians)
e = Inclination = 0.409105177 (in radians)
RAMC = 1.29590697 (in radians)

So putting values into the formula
temp = -( (TAN.89 x SIN .41) + (SIN1.296 x COS .41) ) ÷ COS 1.30
temp = -5.095479952
Asc = -0.193789483

So Ascendant in Degrees = -11.1

Now add 360 degree = Ascendant = 348.9 (hence, Pisces)

but the Ascendant should be VIRGO

Please help me with this, I am clueless, what's the mistake I am
doing ?

in the Astrolog Software they have this extra line -
DegreeFromRadian(Asc)+is.rSid
but I have no idea what is.rSid is. Please suggest me a way through
this...

Thanks
Arpit

Arpit Tambi

2008-09-21 19:35:08 UTC

Permalink

Problem solved :

I was making a terrible mistake in conversions of inverse
trigonometric functions. So if anyone wishes to calculate ascendant on
MS Excel, use the following conversion -

arccot(x) = pi() + arctan(1/x), where x<0

so,

temp = - ( (TAN f x SIN e) + (SIN RAMC x COS e) ) ÷ COS RAMC
ASC(in radians) = pi() + ARCTAN(1/temp)

But now I'm facing another problem -
In this article http://www.chrismitchell.bristolastrology.net/ascendant_calculation.html
by Chris Mitchell, its mentioned that the if it's a Southern latitude,
swap the signs round

But when I use above formula it automatically gives me the correct
ascendant and I don't need to swap the opposite signs. So is it normal
or am I making a calculation mistake again? Please help.

Post by Arpit Tambi
Hi all
I am a new member to this group. I found this group while searching
the math of astrology.
Basically my curiosity to know 'how astrology works' took me here. I
am trying to calculate a simple birth chart so that I can understand
what happens in the background.
I've been able to successfully calculate the MidHeaven(MC) but am
totally clueless to the Ascendant calculations.
I'm interested in calculating the birth chart for a person born
midnight GMT, 6 December 1970. So the following details are obtained -
Local Sidereal Time - 4 hours 57 min
RAMC = 74.25
Inclination = 23.44
Latitude at GMT = 51.5
MC = 74.68 (Hence Gemini)
how to calculate Ascendant?
I tried this formula (read this in the great article An Astrological
House Formulary by Michael P. Munkasey and the same formula has been
used in Astrolog Software)
ASC = ARCCOT (- ( (TAN f x SIN e) + (SIN RAMC x COS e) ) ÷ COS RAMC)
its not possible to get ARCCOT directly in MS Excel, also all values
have to be in Radians not degrees so I used following instead -
temp = - ( (TAN f x SIN e) + (SIN RAMC x COS e) ) ÷ COS RAMC
ASC(in radians) = ARCTAN(1/temp)
Here, f = latitude = 0.898844565 (in radians)
e = Inclination = 0.409105177 (in radians)
RAMC = 1.29590697 (in radians)
So putting values into the formula
temp = -( (TAN.89 x SIN .41) + (SIN1.296 x COS .41) ) ÷ COS 1.30
temp = -5.095479952
Asc = -0.193789483
So Ascendant in Degrees = -11.1
Now add 360 degree = Ascendant = 348.9 (hence, Pisces)
but the Ascendant should be VIRGO
Please help me with this, I am clueless, what's the mistake I am
doing ?
in the Astrolog Software they have this extra line -
DegreeFromRadian(Asc)+is.rSid
but I have no idea what is.rSid is. Please suggest me a way through
this...
Thanks
Arpit

d***@gmail.com

2013-11-26 14:21:10 UTC

Permalink

Hello,

I am a quit curious about all these calculation, as now a day trying to understand the calculation on which all the predictions are based, As per the formula given can you let me know what is RAMC and how it can be calculated ???

d***@gmail.com

2013-12-06 11:42:25 UTC

Permalink

Hello,

I am very curious about all the calculation done by mathematics for the prediction of a person, i am trying to find how all this work so while serching find this post, and its seems that this is something i was searching for... as per the given formula, can u let me know what is RAMC and how it can be calculated

Thank you

======================================= MODERATOR'S COMMENT:
Normally repetition of posts within a month are not allowed, but as this is obviously a clarification of the earlier post, it is now allowed.

unknown

2013-12-18 00:26:18 UTC

Permalink

It stands for Right Ascension of the Midheaven (Medium Coeli) - that is, the
position of the Midheaven in celestial longitude, which differs very
slightly from its position in the Zodiac (i.e. ecliptic).

From what I found when I did a Web search, it seems to be another way of

expressing the sidereal time, but I don't know how "4 hours 57 minutes" is
translated into "74.25 degrees". I'm afraid I've never really done these
calculations myself.

Can anyone do better?
--
A. B.

My e-mail address is zen177395 at zendotcodotuk, though I don't check that
account very often.
Post unto others as you would have them post unto you.

Hello,
I am very curious about all the calculation done by mathematics for the
prediction of a person, i am trying to find how all this work so while
serching find this post, and its seems that this is something i was
searching for... as per the given formula, can u let me know what is RAMC
and how it can be calculated
Thank you

Normally repetition of posts within a month are not allowed, but as this
is obviously a clarification of the earlier post, it is now allowed.

Todd Carnes

2014-01-13 03:36:04 UTC

Permalink

Post by unknown

From what I found when I did a Web search, it seems to be another way of

expressing the sidereal time, but I don't know how "4 hours 57 minutes" is
translated into "74.25 degrees". I'm afraid I've never really done these
calculations myself.
Can anyone do better?

To convert from hours to degrees all you do is multiply decimal hours by 15 degrees/hour.

So, for you example...

4 hours 57 minutes = 4 hours + 57/60 hour = 4.95 hours

4.95 hours * 15 degrees/hour = 74.25 degrees

Todd

a***@gmail.com

2014-05-09 06:36:06 UTC

Permalink

As per South and 12 ... The ascendant in the South Hemisphere is the same as in the North IF you add 12 hours (mod 24) to the time and 180 degrees (mod 360) to the RA. Enables you to use tables (or calculate) data for one hemisphere for the other. FYI

hawdogblue

2014-06-24 08:40:27 UTC

Permalink

Post by Arpit Tambi
Hi all
I am a new member to this group. I found this group while searching
the math of astrology.
Basically my curiosity to know 'how astrology works' took me here. I
am trying to calculate a simple birth chart so that I can understand
what happens in the background.
I've been able to successfully calculate the MidHeaven(MC) but am
totally clueless to the Ascendant calculations.
I'm interested in calculating the birth chart for a person born
midnight GMT, 6 December 1970. So the following details are obtained -
Local Sidereal Time - 4 hours 57 min
RAMC = 74.25
Inclination = 23.44
Latitude at GMT = 51.5
MC = 74.68 (Hence Gemini)
how to calculate Ascendant?
I tried this formula (read this in the great article An Astrological
House Formulary by Michael P. Munkasey and the same formula has been
used in Astrolog Software)
ASC = ARCCOT (- ( (TAN f x SIN e) + (SIN RAMC x COS e) ) Ã· COS RAMC)
its not possible to get ARCCOT directly in MS Excel, also all values
have to be in Radians not degrees so I used following instead -
temp = - ( (TAN f x SIN e) + (SIN RAMC x COS e) ) Ã· COS RAMC
ASC(in radians) = ARCTAN(1/temp)
Here, f = latitude = 0.898844565 (in radians)
e = Inclination = 0.409105177 (in radians)
RAMC = 1.29590697 (in radians)
So putting values into the formula
temp = -( (TAN.89 x SIN .41) + (SIN1.296 x COS .41) ) Ã· COS 1.30
temp = -5.095479952
Asc = -0.193789483
So Ascendant in Degrees = -11.1
Now add 360 degree = Ascendant = 348.9 (hence, Pisces)
but the Ascendant should be VIRGO
Please help me with this, I am clueless, what's the mistake I am
doing ?
in the Astrolog Software they have this extra line -
DegreeFromRadian(Asc)+is.rSid
but I have no idea what is.rSid is. Please suggest me a way through
this...
Thanks
Arpit

So putting values into the formula

Post by Arpit Tambi
temp = -( (TAN.89 x SIN .41) + (SIN1.296 x COS .41) ) ï¿œ COS 1.30
temp = -5.095479952
Asc = -0.193789483
So Ascendant in Degrees = -11.1
Now add 360 degree = Ascendant = 348.9 (hence, Pisces) (Actually correct if you add 180 deg it comes to 168 54? 18 Virgo within minutes) I don't understand how you got -5.095479952 from above.Do I just multiply .89 x .41 and add to 1.296 x .41 etc.? I see that ARCCOT of -5.095 = .193789483 radians = -11.1 degrees .But I cannot arrive at -5.0954 Could you please explain this? Thank You Harold

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