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Ascendant Calculation
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gothic5



Joined: 09 Jun 2014
Posts: 20

Posted: Sun Jun 29, 2014 7:01 am    Post subject: Ascendant Calculation Reply with quote

I have been having a hard time getting the trig example right from Michael Munkasey's book (page 430) for ascendant calculation.

ASC = ARCCOT (- ( (TAN f x SIN e) + (SIN RAMC x COS e) ) COS RAMC At first the minus sign before the TAN threw me off,but I was told to multiply Tan Latt x Sin Obl and then change to a negative number. I did this ,then proceeded to add this negative number to the second product and divide by Cos Ramc .I calculated -.3413+.7873=.4459/-.5134=-.0674 After calculating ARCCOT for -.0674 I got -86 deg 8min 38 sec. My Ascendant is 24 27 Libra and no multiple of 90 deg added to -86 8 38 gives me this.I tried this with other charts and also got it wrong.I know it is a lot of numbers and words but just curious in case someone can point out my error in the calculation.Thank You- Harold
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Ursa Major



Joined: 28 Jul 2010
Posts: 24
Location: Limburg

Posted: Sun Jun 29, 2014 6:19 pm    Post subject: Re: Ascendant Calculation Reply with quote

gothic5 wrote:
I have been having a hard time getting the trig example right from Michael Munkasey's book (page 430) for ascendant calculation.

ASC = ARCCOT (- ( (TAN f x SIN e) + (SIN RAMC x COS e) ) COS RAMC At first the minus sign before the TAN threw me off,but I was told to multiply Tan Latt x Sin Obl and then change to a negative number. I did this ,then proceeded to add this negative number to the second product and divide by Cos Ramc .I calculated -.3413+.7873=.4459/-.5134=-.0674 After calculating ARCCOT for -.0674 I got -86 deg 8min 38 sec. My Ascendant is 24 27 Libra and no multiple of 90 deg added to -86 8 38 gives me this.I tried this with other charts and also got it wrong.I know it is a lot of numbers and words but just curious in case someone can point out my error in the calculation.Thank You- Harold


Are you sure formula is correct ?

Is it not

Asc= arccot( (cos( RAMC+90) - tan(e) * tan( f ) ) * cos(e) / sin( RAMC+90) )


Last edited by Ursa Major on Tue Jul 01, 2014 8:12 am; edited 1 time in total
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gothic5



Joined: 09 Jun 2014
Posts: 20

Posted: Tue Jul 01, 2014 3:50 am    Post subject: ascendant calculation Reply with quote

Asc= arccot( (cos( RAMC+90) - tan(e) * tan( f ) ) * cos(e) / sin( RAMC+90) ) Thank You for your reply-I have been trying to get my asc. (24 27 Libra ) without much luck.But with above formula I got 204 07 33(24 07 Libra) RAMC +90 =210 53 32 OBL 23 26 34 LATT 40n38- I wasn't sure if -1.2917 was right for -.85813 minus .43362 (approx) which I Multiplied by TAN LATT (.858113329) and got -1.108476442. I then divided COS OBL by SIN RAMC +90 .917457854/-.513424766 and got .404033088 which I multiplied by -1.108476442 and got -.447861159.ARCCOT -.447861159 =-65 52 28 + 270 =204 07 33 24 07 LIBRA.I used an online ARCCOT calculator since I don't know how to with mine.It only has 4 decimal-Maybe this affects answer.Sorry about all the decimals I was using exact calculator #'s If you can make sense of this post I would appreciate any comments-Thanks again-Harold
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Ursa Major



Joined: 28 Jul 2010
Posts: 24
Location: Limburg

Posted: Tue Jul 01, 2014 7:59 am    Post subject: Reply with quote

Beneath the correct calculation

RAMC 120 53 32 = 120,8922222222
RAMC + 90 = 210,8922222222
cos(ramc+90) = -0,8581346099
sin(ramc+90) = -0,5134247669

E 23 26 34 = 23,4427777778
cos(e) = 0,9174578541
tan(e) = 0,4336253548

Latitude 40 38 = 40,6333333333
tan( lat ) = 0,8581133296

numerator is = -1,1286881273 see the formula (cos( RAMC+90) - tan(e) * tan( lat ) ) * cos( e )
denominator is = -0,5134247669 see the formula sin( RAMC+90)

Gives = 2,1983515406
arccot = 65,5398622654
if you subtract this from 270 you got:
204,4601377346
is equal to 24 Libra 27' 41

You have first to multiply tan(lat) with tan(e) !!!!
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gothic5



Joined: 09 Jun 2014
Posts: 20

Posted: Wed Jul 02, 2014 5:04 am    Post subject: Ascendant Calculation Reply with quote

I would like to Thank You for taking the time to explain this.I did not understand the order to follow but after you explained step 1 I was able to get my correct Ascendant.Could you suggest a book that I could use? I bought Michael Munkasey's book Astrological Thesaurus really to calculate Placidus and also other Systems which use projection to the Great Circles.But it looks like I ran into trouble from the word go at Ascendant Calculation.I am glad I got it now-I spent many hours with Munkasey's formula and also tried to do one in the Michelsens Table of Houses.I heard there might have been some errors in some editions of Munkasey's book. Harold
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cintia.machado



Joined: 29 Jun 2014
Posts: 3
Location: Brazil

Posted: Wed Jul 02, 2014 5:13 pm    Post subject: Reply with quote

Is it possible to know one's ascendant without having the time of birth?
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james_m



Joined: 05 Dec 2011
Posts: 2684
Location: vancouver island

Posted: Wed Jul 02, 2014 7:04 pm    Post subject: Reply with quote

cintia - interesting question. welcome to skyscript!

some might be inclined to answer in the affirmative regarding the sign, but getting the degree of the sign - that is highly unlikely.. so, i am making a distinction between the sign and the degree of the sign.. hopefully you know what the distinction is!

i have heard a higher number of births happen around sunrise, then other times of the day.. i can't remember if someone has corrected me on this or not here in the past.. it might or might not be true..

the way i have gone about this is trying to imagine the possibilities of a particular sign rising when i don't know the time of birth. it hinges on my understanding of how the sign rising would behave in connection with the data for the date in question.. it would have to be modified if there was a planet in that particular sign as well and i would keep an open mind as to whether i could actually do this accurately by sign only as well! it is essentially chart rectification that you are asking about!

i was thinking about this recently with a new friend i had developed who knew the day and year he was born, but not the time of day he was born.. he is born on oct 31 1946.. what i first do is a day chart for noon.. that gives me the planet locations. the moon can vary up to 14 degrees over the course of a day so a noon position can mean the moon is up to 7 degrees out from the noon time. this will help clarify what the moon sign is for the most part, or might help guide you in a particular direction..

since i have noticed an undue number of university professors with gemini accentuated in the music world, i have concluded rightly or wrongly there is a high possibility of my friend having gemini rising. this is due a combo of observations on him and specifically how i interact with him..

so in answer to your question, i think it is possible to isolate the sign, but not the degree, unless you have a lot of data to work with on the person - important dates of events in their life and etc, and even then it is challenging and speculative work.. this falls under the area of rectification work in astrology.. cheers james
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cintia.machado



Joined: 29 Jun 2014
Posts: 3
Location: Brazil

Posted: Thu Jul 03, 2014 4:29 pm    Post subject: Reply with quote

Hi, James

Thanks for the answer!

I'm trying to find my mother's rising (it would be great if I knew at least the sign). I hadn't thought about the variation in the degrees of the moon. Maybe it would change the chart I got for her - a simplified one at astro.com (there is an "unknown time" option). It could change the aspects. But it gives a general picture, a starting point.

I hope your guess about your gemini rising friend is right, who knows...
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james_m



Joined: 05 Dec 2011
Posts: 2684
Location: vancouver island

Posted: Thu Jul 03, 2014 5:51 pm    Post subject: Reply with quote

hi cintia,

this is no scientific study on my part, but often family members share a number of astro signatures in common. if you have the specific data on other family members, it can help guide you sometimes.. for example - my dad - sun in scorpio - both my brother and i have scorpio rising(ascendant) . my mom -sun in cancer and my sister has cancer rising.. maybe it is just a coincidence.. i believe my mom had scorpio rising as well, but i am going on an approx time for her, so maybe that is part of it too.. this might give you more to consider. perhaps others here will offer some insight that could help guide you. reading general descriptions on what a particular rising sign means, or physical traits of a particular rising sign has never really appealed to me as a means of doing this for a number of reasons. mostly i think the appearance is strongly modified by planets aspecting the ascendant, and of course physical appearance has a strong association with the rising sign/ascendant in astrology.
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cintia.machado



Joined: 29 Jun 2014
Posts: 3
Location: Brazil

Posted: Fri Jul 04, 2014 7:14 pm    Post subject: Reply with quote

That's true! My father is a Leo, and I have a Leo ascendant. Both my mom and my brother have Aquarius moon, and my moon squares Uranus. My baby has an Aquarius ascendant. My mom is a Scorpio and my sister has the Moon in Scorpio.

It must be very interesting to study family patterns...
(Looking at our sibling's sun and moon, for example, and finding out how each one sees a specific and different facet of the same parents).

Thanks for the insight!
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gothic5



Joined: 09 Jun 2014
Posts: 20

Posted: Fri Dec 12, 2014 4:45 am    Post subject: Question of Lattitude Reply with quote

Just another question about above subject.I recently read David McCanns article about getting Regiomantus cusps from Placidus tables.He says to subtract 6 hours from Local Sidereal Time of chart.Ascendant at equator for this LST is MC of chart.I tried applying formula Asc= arccot( (cos( RAMC+90) - tan(e) * tan( f ) ) * cos(e) / sin( RAMC+90) ) Is this possible at equator with lattitude 0?
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gothic5



Joined: 09 Jun 2014
Posts: 20

Posted: Fri Dec 12, 2014 9:28 pm    Post subject: Ascendant Calculation Reply with quote

I was able to get 28 45 Cancer as ascendant with LST 30 53 30 using a calculator and interpolating with table of houses.I tried also with formula Asc= arccot( (cos( RAMC+90) - tan(e) * tan( f ) ) * cos(e) / sin( RAMC+90) ) but left out the Lattitude.Is it possible to calculate by using Asc= arccot( (cos( RAMC+90) - tan(e) ) * cos(e) / sin( RAMC+90) )?
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Ursa Major



Joined: 28 Jul 2010
Posts: 24
Location: Limburg

Posted: Mon Dec 15, 2014 6:42 pm    Post subject: Re: Ascendant Calculation Reply with quote

gothic5 wrote:
I was able to get 28 45 Cancer as ascendant with LST 30 53 30 using a calculator and interpolating with table of houses.I tried also with formula Asc= arccot( (cos( RAMC+90) - tan(e) * tan( f ) ) * cos(e) / sin( RAMC+90) ) but left out the Lattitude.Is it possible to calculate by using Asc= arccot( (cos( RAMC+90) - tan(e) ) * cos(e) / sin( RAMC+90) )?


No

The original formula is:

Asc = arccot( ( cos( RAMC + 90 ) - tan(e) * tan( f ) ) * cos( e ) / sin( RAMC + 90 ) )


If the latitude ( = f ) is 0.0... and only then, then you can use the formula :

Asc = arccot( ( cos( RAMC + 90 ) ) * cos( e ) / sin( RAMC + 90 ) )

If you multiplied something with a value 0.0 . the result will be always 0!
So that part of the formula you can omit.

Greetings from the Netherlands,


Last edited by Ursa Major on Thu Dec 18, 2014 12:12 pm; edited 2 times in total
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Ursa Major



Joined: 28 Jul 2010
Posts: 24
Location: Limburg

Posted: Mon Dec 15, 2014 6:48 pm    Post subject: Re: Question of Lattitude Reply with quote

gothic5 wrote:
Just another question about above subject.I recently read David McCanns article about getting Regiomantus cusps from Placidus tables.He says to subtract 6 hours from Local Sidereal Time of chart.Ascendant at equator for this LST is MC of chart.I tried applying formula Asc= arccot( (cos( RAMC+90) - tan(e) * tan( f ) ) * cos(e) / sin( RAMC+90) ) Is this possible at equator with lattitude 0?



Yes. It is possible.
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gothic5



Joined: 09 Jun 2014
Posts: 20

Posted: Thu Dec 18, 2014 3:28 am    Post subject: Ascendant Calculation Reply with quote

Thanks again for the reply.My interest in calculating points on the chart (asc mc house cusps for different systems) came from trying to understand how the concepts applied to the Great Circles.I spend a lot of time on my astronomy program which provides a good insight although the view seems to be one on the Earth toward the outer region.In reading astrological books or texts that explain chart calculation the diagrams show a view toward Earth from outside.Either way it is not always clear to me how projection of a particular circle(ecliptic,equator or other) onto another results in the point of a cusp.But I noodle around with different ideas-like putting planets at the cusp points and seeing how they change with different house systems while observing their astronomical points.Ascendant Calculation (and MC) usually are pretty clear (ecliptic & horizon) but I know some systems like Morinus can use another point for the first house cusp.Best wishes from cyberspace HS
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