Calculating Ascendant using Munkasey's formula

[arca]

Hi all,

I'm new to this group and so far it's the only place where I've found
info related to calculating the Ascendant using mathematical formulas.

I have the formula for calculating the Ascendant from An Astrological
House Formulary by Michael P. Munkasey, mentioned in another realted
thread:

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

I want to calculate the Ascendant for the Equal House System used by
vedic Astrology. My problem is, the formula calculates the ARCCOT of
x. The ARCCOT will always be in a range of 90 degrees. So how can my
Ascendant ever go around the 360 degrees if it's in a range of 90?

I have already confirmed this by applying the formula to a real-case
scenario. I use the same data several times, only increasing one hour
to the time of birth each time. The answer goes up to 275 degrees and
then jumps to 90 degrees from one hour to the next. And it never
really gets the answer right, comparing with the actual ascendant.

Do I have to do some kind of conversion after using the formula? I
think it may have to do with quadrants but I'm not sure....

Any leads would be very appreciated. I can't use tables or lists of
ascendants to calculate this, I need to use the data given to me by
the JPL Novas 3.0 software.

Thanks,

Alicia

[arca]

Post by arca
Hi all,
I have the formula for calculating the Ascendant from An Astrological
House Formulary by Michael P. Munkasey, mentioned in another realted
ASC = ARCCOT (- ( (TAN f x SIN e) + (SIN RAMC x COS e) ) ÷ COS RAMC)
I want to calculate the Ascendant for the Equal House System used by
vedic Astrology.  My problem is, the formula calculates the ARCCOT of
x.  The ARCCOT will always be in a range of 90 degrees.  So how can my
Ascendant ever go around the 360 degrees if it's in a range of 90?
Do I have to do some kind of conversion after using the formula?  I
think it may have to do with quadrants but I'm not sure....

I answered my own question. Turns out I need to check if the
resulting ASC is less tha zero. If it is, add PI. And, if COS(RAMC) is
less than 0, add PI.

so:

ASC = ARCCOT (- ( (TAN f x SIN e) + (SIN RAMC x COS e) ) ÷ COS RAMC)
IF(ASC <0)
ASC += PI
IF(COS(RAMC) <0)
ASC += PI

This is assuming that we're using programamtical functions that use
radians for calculation. The radians to degrees conversion is done
after this modification. Also, the answer is tropical, not sidereal.

I wonder why Munkasey doesn't mention this in his Formulary. It is
very confusing as it is. Hope it helps someone else out there.

[t***@gmail.com]

IF(ASC <0)
ASC += PI
IF(COS(RAMC) <0)
ASC += PI

I wonder why Munkasey doesn't mention this in his Formulary. It is
very confusing as it is. Hope it helps someone else out there.
===

Hi Alicia ... thank you for these 2 hints!
Munkasey's formula is realy confusing in this point.