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g-battaglia / kerykeion

Data driven Astrology 💫
Kerykeion is a python library for astrology. It can generate SVG charts and extract all data about a birthchart, a synastry chart and a transit chart.
https://kerykeion.net
GNU Affero General Public License v3.0
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Why was conjunction an hour ahead of the eclipse? #120

Open teledyn opened 2 months ago

teledyn commented 2 months ago

This is bugging me, I'm sure there's a simple solution, I just tested Kerykeion and it's the same: all my astrology softwares say the Sun and Moon were conjunct April 8, 2024 as seen in Niagara Falls, NY at 14:21 EDT and at 19.4 Aries. Astronomy software on the other hand say the eclipse happened exactly one hour later and one degree before, R.A. 1h10m = 18 Aries. The eclipse certainly did happen at 15:21, I was there!

So why this difference? I thought conjunct and eclipse both meant centered on the same degree, and I also though R.A. and the Zodiac were both First Point of Aries. Am I going to slap myself in the head when you tell me why this is?

Apologies for posting a non-issue issue, but I didn't have anywhere else to ask where I wouldn't just get puzzled stares :)

kubow commented 3 weeks ago

On a normal occasion, I would refer you to https://astronomy.stackexchange.com/ but since I know they are not very keen on answering astrology-related questions, I will try to explain here briefly:

I must admit also slapped my head several times because of these things, not an easy matter...

teledyn commented 3 weeks ago

Thanks so much, and this all makes sense except for one detail: on the subsequent full moon, they agreed exactly! So can I beg just a little more math?

On Wed, Aug 21, 2024 at 3:35 AM Kube Kubow @.***> wrote:

On a normal occasion, I would refer you to https://astronomy.stackexchange.com/ but since I know they are not very keen on answering astrology-related questions, I will try to explain here briefly:

  • there is a difference between ecliptic coordinates (used in astrology) and equatorial coordinates (used in astronomy)
  • conjunction in astrology happens when two celestial bodies are aligned with respect to the ecliptic longitude
  • eclipse happens when the Sun, Moon, and Earth align so that the Moon passes between the Earth and Sun, casting a shadow
  • The one-hour time difference and the one-degree difference stem from how the positions of the Sun and Moon are measured differently in the two coordinate systems. Ecliptic longitude (used in astrology) and Right Ascension (used in astronomy) do not correspond exactly because of the tilt of the Earth's axis (about 23.5°).

I must admit also slapped my head several times because of these things, not an easy matter...

— Reply to this email directly, view it on GitHub https://github.com/g-battaglia/kerykeion/issues/120#issuecomment-2301348328, or unsubscribe https://github.com/notifications/unsubscribe-auth/AAPLTK3VENFNAVMFXFJKAM3ZSQ7NHAVCNFSM6AAAAABKIO55HCVHI2DSMVQWIX3LMV43OSLTON2WKQ3PNVWWK3TUHMZDGMBRGM2DQMZSHA . You are receiving this because you authored the thread.Message ID: @.***>

-- Gary Lawrence Murphy - Toronto CA - Fediverse @.***> - Tumblr https://teledyn.tumblr.com - Blog https://blog.teledyn.com - Home https://www.teledyn.com/

kubow commented 3 weeks ago

There can be multiple factors involved. If you compare both coordinate systems, the difference between ecliptic and equatorial plane varies over time. But this is slowly becoming a matter for that Astronomy Stack exchange I mentioned previously :)

teledyn commented 3 weeks ago

My main misunderstanding was somehow getting it stuck in my brain that RA was ecliptic, but it's longitude. Oops. What threw me was when the difference was exactly an hour 😅

On Tue, Aug 27, 2024, 10:37 a.m. Kube Kubow @.***> wrote:

There can be multiple factors involved. If you compare both coordinate systems https://en.wikipedia.org/wiki/Astronomical_coordinate_systems, the difference between ecliptic and equatorial plane varies over time. But this is slowly becoming a matter for that Astronomy Stack exchange I mentioned previously :)

— Reply to this email directly, view it on GitHub https://github.com/g-battaglia/kerykeion/issues/120#issuecomment-2312750752, or unsubscribe https://github.com/notifications/unsubscribe-auth/AAPLTK77Q3SOOLOWYVMIVXDZTSFI3AVCNFSM6AAAAABKIO55HCVHI2DSMVQWIX3LMV43OSLTON2WKQ3PNVWWK3TUHMZDGMJSG42TANZVGI . You are receiving this because you authored the thread.Message ID: @.***>