All 52 chapters
  1. Part 1 · The sky and the chart
  2. The sky above us
  3. Time and place of birth
  4. Two zodiacs
  5. How a chart is drawn
  6. Part 2 · The building blocks
  7. The 9 planets
  8. The 12 signs
  9. The 27 nakshatras
  10. The 12 houses
  11. The lagnas
  12. Part 3 · How planets work together
  13. How planets interact
  14. Friends, dispositors, exchanges
  15. House lords
  16. Reading one placement
  17. Part 4 · Strength and condition
  18. Dignity in depth
  19. A planet's mood
  20. Planetary strength
  21. Ashtakavarga in depth
  22. Part 5 · Patterns: yogas and doshas
  23. Yogas
  24. Doshas
  25. Part 6 · The nakshatras up close
  26. Reading a nakshatra
  27. Tara Bala
  28. Part 7 · Divisional charts
  29. Divisional charts
  30. Navamsa in depth
  31. Part 8 · Timing
  32. Dashas
  33. Transits
  34. The annual chart (Tajika)
  35. Part 9 · Relationships
  36. Compatibility
  37. Marriage in depth
  38. Part 10 · Advanced systems
  39. Special points
  40. Jaimini astrology
  41. Arudha padas
  42. KP astrology
  43. Nadi astrology
  44. Part 11 · Choosing the moment
  45. Panchanga
  46. Muhurta
  47. Prashna (horary)
  48. Part 12 · Life areas
  49. Career, money and business
  50. Travel, abroad, spirituality
  51. Health and longevity
  52. Karma and past lives
  53. Remedies
  54. Rectifying a birth time
  55. Part 13 · Western astrology
  56. Western astrology basics
  57. Aspects and chart shapes
  58. Western prediction
  59. Synastry
  60. Horary and electional
  61. Part 14 · The wider world
  62. Mundane astrology and eclipses
  63. Astrocartography and branches
  64. Part 15 · Putting it all together
  65. How it all fits
  66. How AstroMatch4u scores a chart
  67. Using astrology well
Part 1The sky and the chart
CHAPTER 2

Time and place of birth

Why does the exact minute and town matter so much?

A chart needs three facts: date, time and place. The date fixes where the planets are. The time and place together fix which sign was rising, and so every house. Because the sky turns about 1° every 4 minutes, a few minutes can change the ascendant degree, and about two hours changes the rising sign itself.

a photo taken from a moving train. The landscape (the planets) barely changes in a minute, but the window frame (the houses) slides past quickly.

The kinds of clock time

Solar timeTime by the Sun itself: noon is when the Sun is highest. Every town has its own.
Local Mean Time (LMT)Solar time smoothed out so every day is exactly 24 hours. It changes by 4 minutes for every degree of longitude you travel.
Standard timeOne clock time for a whole region. India uses IST, set by the 82.5° E meridian, which is UTC + 5:30.
Time zonesThe world's standard times, mostly in whole or half hours from UTC.
UTCCoordinated Universal Time, the world reference clock (close to Greenwich Mean Time). Charts are calculated in UTC.
Daylight Saving TimeClocks moved an hour ahead in summer in many countries. A birth in summer in the UK or USA needs that hour taken off.
Sidereal time"Star time". The Earth turns once against the stars in 23 h 56 m, four minutes shorter than a solar day. It decides which sign is rising.
Sunrise, noon, sunsetVedic astrology counts the day from sunrise, not midnight. Local noon is when the Sun crosses the meridian.

Traps in old Indian birth times

  • During the Second World War (1942–45) clocks in India ran one hour ahead ("war time"). A birth then needs an hour taken off.
  • Before IST was used everywhere, Kolkata kept its own Calcutta Time (until 1948) and Mumbai its own Bombay Time (until 1955).
  • Old certificates often round to the nearest quarter or half hour. "Around 6 in the morning" can be wrong by enough to change the ascendant.

The place

The place gives the latitude (how far north or south) and longitude (how far east or west). Longitude converts clock time to star time; latitude changes how long each sign takes to rise. Near the equator every sign rises in about two hours; far north, some signs rise in under an hour and others take three or more.

Birth time accuracy matters differently for each part of a chart. Planet signs are safe with any time on the right day (except the fast Moon near a sign edge). The ascendant needs the time to within a few minutes. The finest divisional charts need it to within a minute or two (the rectification chapter explains what to do when you are not sure).

your town is looked up for its latitude and longitude, and your time is converted with the international time-zone database, which includes India's wartime clock change.

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