Q&A and discussion on Quotidian variations of progressions.
DDonovanKinsolving wrote:I'm sure Jupiter Sets at Dawn meant to add 5:20 to the RAMS, Right Ascension of the Mean Sun. JS@D is describing how to compute Besselian Time natally and for the time in question. Once that typo is understood, the rest falls in place.Freya wrote:can you please explain how you arrived at 5 hours and 20 minutes? ThanksJupiter Sets At Dawn wrote: Add 5 hours 20 minutes to both RAMCs
DDonovanKinsolving wrote:FINDING THE MEAN SUN WITH SOLAR FIRE
Go to Dynamic > Ephemeris generator.
Under the section Period of Ephemeris, select a reasonably short period of time, such as 5 days, that includes the date for which you're calculating and the day after. For "Start Time", be sure to enter 12:00. That's important.
Frequency of Entries: Every 1 Day.
Ephemeris Time Zone: You can use your own time zone for convenience, but to double-check your results, I recommend GMT so you can cross-compare your results with a noon ephemeris. When you feel comfortable, you can switch to your own time zone. That's one of the flexibilities that gives computer programs such as SF an advantage over print media.
Lunar Node: Your choice. It's not relevant here.
Items to list: It's important to tick "Sidereal Time." SF seems to require at least one real planet so tick "Right Ascension" as well. Let's keep it simple for now and untick the other options.
Points to list: "Transiting Chart Points:" Use whatever you want, but for this exercise stay simple and create a point chart that consists of only the Sun. By this time, you've set up the ephemeris generator to show the RA of both the Mean Sun and the transiting Sun.
Precision: Your choice, but in this instance I prefer "Seconds of Arc." It won't affect the Sidereal Time, but it will affect the Sun and any other planets you're choosing to list.
Notation: Zodiacal. (or "Decimal Degs" if you're comfortable with it.)
Start the ephemeris generator. The Sidereal Time is identical with the Right Ascension of the Mean Sun. Since you've included the Sun as a point, you also have the RA of the transiting Sun for work requiring that.
Interpolate by usual means for the desired time, keeping in mind that you are figuring from noon, not midnight.
FOR MORE ADVANCED USERS
Set the Frequency of Entries to 1 Hour.
For every hour after 12:00, subtract an hour from the Sidereal Time. For example, 13:00 is one hour after 12:00, so subtract one hour from Sidereal Time. For 03:00 (that's AM), it's 15:00 after 12:00, so subtract fifteen hours from Sidereal Time. Your results should show a smooth advance of 0:00:10 (sometimes 00:00:09) per hour from the noon position.
DDonovanKinsolving wrote:Let's check this!Jupiter Sets At Dawn wrote:So May 24, 2013 at 6:16:13 PM CST would be RA 05:54:40 so 2013.2462963.
Go to Solar Fire's Ephemeris Generator.
Start date: May 24, 2013. Start Time: 12:00:00.
End date: May 25, 2013. End Time 12:00.
Frequency of Entries: 1 Hour.
Start the Ephemeris.
Add 6 hours to 18:00 CST to find that it is equivalent to 00:00 the next day. In the ephemeris, go to May 25 2013 00:00. The RA of the Mean Sun is 16:10:57 - 12:00:00 = 04:10:57. Since you can see that that the RAMS is advancing 10 seconds per hour, and that this is 1 second per 6 minutes, and you can round 0:16:13 to 18 minutes, so you add 3 more seconds to get 04:11:00. [You can use a table for this part, if you don't want to engage your brain just a little.] Add 5:20:00 to that and the result is a Besselian Time of 2013 09:31:00.
Compare that to The American Sidereal Ephemeris. At midnight on May 25, 2013 the RAMC is 16:10:58. By happy coincidence, this is already close to our target time. Subtract 12 hours (you can visualize this as the Mean Sun being on the IC instead of on the MC) add the requisite 3 seconds and you get RAMS of 04:11:01, in essential agreement with the prior results.
This was from a few years ago. Was this spreadsheet ever uploaded onto this site? I would love to have a copy of it.DDonovanKinsolving wrote:Here is a short version of a progression calculator I've developed. For the example, I've used Susan Walker from "Primer of Sidereal Astrology" for a fast comparison of the Q1 and Q2 results.
Thank you in advance for any information.
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