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Sidreal Time (ST) Conversion Question

1 by TerpBKS
Okay, so now I'm pulling out my hair already, LOL!

As noted in my other post, I'm using Parkers' Astrology to start out my studies in Astrology. However, I'm stumped! For those of you who may have the book, I'm on page 99.

My birthdate is Jan. 5, 1987, and the longitute and latitude of my birthplace is 37? 16' N, 81? 13' W. So according to the book my GMT is 15:23. The chart given states that my ST=6.57. After adding the extra minute it becomes 6.58.

The book uses an example in which they use the information with the ST midnight time, and that threw me for a loop. However, I am pretty sure that I am to skip over that part because my time is 6.58 not "18.47.41".

The big one that stumps me is when I look at part six where it talks about how to convert the time from GMT to local GMT. Then gives a chart that tells you how many extra minutes to subtract. Well from what I understand, I am to take 6.58 and subtract 5.24 which leaves me 1.34. Then the chart tells me to subtract another 1.24 which leaves me with .10.

What am I doing wrong? LOL!

I even went to the alabe.com website and put in my information and the chart they are giving me is completely different than what I'm coming up with. So confused.

Please help!

Brian

Re: Sidreal Time (ST) Conversion Question

2 by Juan
I will assume that the GMT of your birth is indeed 15:23 as you say, which means that you were born at 10:23 a.m. EST.

You must convert 15:23 to sidereal time or "accelerate", multiplying by 1.002738 or adding 10s for each hour, the result is 15:25:32. To this you must add the ST at 0h in Greenwich, which is 6:56:13. The result is 22:21:45. This is the sidereal time at Greenwich when you were born. Now you must subtract the longitude of your birth place (81?13'/15 = 5:24:52). The result is 16:56:53 or 16h56m53s. This is the sidereal time at the moment and place you were born, from which you calculate the houses (ASC = 4,53 Pisces, MC = 15,28 Sagittarius).

Juan

3 by TerpBKS
Okay, so I was typing up a reply and hit a button then it was erased. Darn!

Thanks, Juan. I have some questions for you.

How do you multiply a decimal and time and then convert back to a decimal? Also, when you accelereated the time, did you add the seconds or multiply by 1.002738?

When you subtracted the longitude of my birthplace, you had a similar conclusion, but you still had seconds . . . just making note of that.

Also, how do you calculate the houses?

So basically there are many methods to achieving ST because the book tells me one method and Juan is telling me a different method.

Is one or the other correct?

According to the book my calculations are as follows:

15.23 + 6.56.13 = 21.76.13, or 22.19.13

At this state I am instructed to round off to the nearest minute, so it becomes 22.19.

The book states to add 4 minutes if the interval falls between 21 and 24 hours. So, 22.19 + .04 = 22.23.

I am then instructed to subtract 5.24 as the longitude and then subtract another 1.24 as the correction.

22.23 - 5.24 = 16.99 - 1.24 = 15.74 which becomes 16.15.

Then the book gives a chart in which we find the closest degree and it gives us the MC and Asc. Mine was 6? Saggitarius MC and 20? Pisces Asc.

Am I wrong?

4 by Juan
TerpBKS wrote:Also, how do you calculate the houses?
normally you use a "Table of Houses", unless you want to do it the hard way directly through trigonometry.
So basically there are many methods to achieving ST because the book tells me one method and Juan is telling me a different method.
Is one or the other correct?
the result must be exactly the same regardless of what method you use. The method I outlined is the one given in the first edition of the Parkers' book from 1977.
I am then instructed to subtract 5.24 as the longitude and then subtract another 1.24 as the correction.
With the exception of the last ("1.24") correction, the method is the same, only they are rounding everything to the nearest minute, which will produce accumulated errors in the final result.
22.23 - 5.24 = 16.99 - 1.24 = 15.74 which becomes 16.15.
Are you sure you are not mixing decimals and sexagesimals together?

The final result must be TS = 16h56m53s = 16h57m = 16.948. Any other result is wrong.

J.

5 by TerpBKS
Thanks, Juan.

Okay, I guess it's back to square one. :)

One question though what's a sexagesimal?

Math was my favorite subject in high school and I've forgotten most of it. And I was really surprised to see how much math was involved in Astrology.

And how do you put in something like ST = 16h56m53s = 16h57m = 16.948 on a calculator or a number with ":" between the numbers?

8 by Juan
TerpBKS wrote:I was born at 10:23 PM not AM.
So your time of birth is not 15:23 GMT as you declared, but 3:23 GMT of the next day.

The procedure or formula is very simple:

GMT of birth x 1.002738 + GST 0h - longitude = ST of birth

In your case:

3h23m x 1.002738 = 3h23m33s
Grennwich ST at 0h Jan 6 = 7h00m10s (from a midnight ephemeris)
Greenwich GST at moment of birth = 10h23m43s
minus longitude 5h24m52
Local ST at birth = 4h58m51

With that ST you look into a Table of Houses, which should give the Asc. in 17,29 Virgo and the MC in 15,55 Gem.

Juan

9 by TerpBKS
Thanks Juan.

I'm still trying to figure out how to enter the time into the calculator to get the results that you are getting.

Any suggestions?

ETA: I'm really trying not to be a bother, I'm just trying to get the basics so I can do well and do it correctly.

10 by Juan
TerpBKS wrote:I'm still trying to figure out how to enter the time into the calculator to get the results that you are getting.
(seconds/60+minutes)/60+hours = decimal hours.

J.

11 by TerpBKS
Juan wrote: (seconds/60+minutes)/60+hours = decimal hours.

J.
Awesome. Thanks!

Now how would you convert decimal to time?

I'm learning so much already and taking LOTS of notes.
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