A Tale of Two Cities

Two Different Methods of Time Conversion

Open Letter to Astrological Association members:

Hi Aleksei, David, Penelope, Victor, Bethia, Mark, and the AA community - thanks for the robust discussion in this 8k-member group! I’m grateful for Bethia and Mark’s support, and I’ll address the resistance from some of the participants focusing on the “1-2-3 moment” and the view that time is homogeneous within a time zone.

Aleksei, let’s use a specific example: two astrologers in China on 2025-04-27 at 12:00 pm CCT - one in Fuyuan (134.6732°E, 48.2604277°N), the other in Tashkurgan (75.2042472°E, 37.7682°N), 4859.52 km apart (59.46896° longitude difference, 3.9645973 hours rotational difference), assuming both are observing UTC+8 or the official Asia/Shanghai time. They count “1-2-3” when their clocks both read 12:00 pm CCT. Geometrically, Fuyuan is 59.46896° east, so it’s further along in Earth’s rotation. I chose this date because the Moon’s motion is faster (15.2490888°/day, or 0.6353787°/hour), so over 3.964596 hours, its position shifts by 2°30'51" or 2.514°. At 12:00 pm CCT, the Moon is 28° Aries 32'20" in Fuyuan but 26° Aries 01'29" in Tashkurgan, reflecting this rotational gap.

The view that time is homogeneous within a time zone (12:00 pm CCT for both) assumes a single “1-2-3” moment, so standard software (e.g., Swiss Ephemeris (SE), Solar Fire, AstroGold, Sirius, etc.) show the same Moon position, ignoring the 3.9645969-hour rotational difference. My formula adjusts the input: for Fuyuan, 12:00 pm CCT maps to 04:58:41 UT1; for Tashkurgan, 01:00:49 UT1 (using UTC as a proxy, as UT1-UTC is < 0.9s, a negligible ~0.00016° for the Moon). This 3.9645969-hour UT1 difference aligns with the Moon’s 2.514° shift. If we start with a true simultaneous moment (same UT1), their clocks should read 12:00 pm CCT in Fuyuan but 8:03 am CCT in Tashkurgan - standard software misses this without correction.

This “homogeneous time” view is illogical, especially globally. If all clocks were synchronized to UTC, observers at 0°E and 180°E would both read 12:00 pm UTC, but the Moon’s position would differ by ~7.6° (12 hours rotationally at 0.633°/hour). Synchronizing to UT1 instead would vary CT by longitude (like LMT), ensuring the Moon’s position aligns for all at a New Moon. My formula achieves this without pre-setting clocks, mirroring LMT-to-GMT conversions, by adjusting CT to UT1.

This impacts most charts, not just historical ones. The Moon’s average motion is 0°32'30"/hour (13°/day), but on this date, it’s 0°38'07"/hour (15.2490888°/day). A 1-minute error shifts the Moon by 0°00'38.12", and even at the average 0°00'32.5", which can significantly affect transit predictions. For slow transits near a station, this throws off timing to the Moon’s limbs (calculated precisely via JPL Horizons to 0.001"). Most astrologers use the center-of-body (COB) position, not the limbs (~±0.25° from COB, given the Moon’s ~0.5° arc-diameter), so a slow-mover like Sedna could be off by months in predictions. The Moon’s precise position is critical for all astrologers - Western traditions rely on it for emotional cycles and event timing, while Chinese astrologers, who equate the Moon with the Yin principle, are especially affected due to their wide time zone (spanning ~60° longitude and up to 4 hours rotational difference), making my formula particularly impactful for them.

Let’s test this: on 2025-04-27 at 12:00 pm CCT, use SE for Fuyuan (134.6732°E) and Tashkurgan (75.2042472°E). Standard output will show the same Moon position (27° Ari 55'06"), but applying my correction (adjusting CT to UT1) will reflect the 2.514° difference. The Standard and Proposed Adjusted Charts are calculated using the freeware Astrolog software with the Adjusted Chart macro-activated (Thanks to Walter Pullen!). Aleksei et al., I’d love to collaborate on this experiment - let’s share results!
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Data for Fuyuan and Tashkurgan:
2025-04-27, 12:00 pm CCT (UTC+8 or Asia/Shanghai)

Donghu Resort, Fuyuan, Jiamusi, Heilongjiang, China
134°40'23.52"E or 134.6732°
48°15'37.54"N or 48.2604277°N

Tashkurgan, Kashgar Prefecture, Xinjiang, China
75°12'15.29"E or 75.2042472°
37°46'05.52"N or 37.7682°N

59.4689528° longitude difference
3.9645969 hr. difference
4859.52 km = Distance (Ground length)

Fuyuan Moon = 28° Ari 32'20"
Tashkurgan Moon = 26° Ari 01'29"
Difference = 2°30'51"or 2.514°
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Files for download:
Standard Charts.pdf
Proposed Adjusted Charts.pdf
Google Earth - Two Cities.png
Standard Time Zones of the World.jfif
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