Mark, Noon or Midnight

Definition

A noon or midnight mark is a notation showing the reference time used for planetary positions in an ephemeris or astrological table. Some ephemerides list each day’s positions for noon, while others use midnight. The mark identifies which convention applies and may also indicate the relevant time standard or meridian.

Astrological Meaning

The notation has a technical rather than symbolic meaning. Astrologers compare the stated reference time with the time of the event or birth, then interpolate planetary motion when greater accuracy is needed. A noon-based table and a midnight-based table can display different positions under the same calendar date because they describe the sky twelve hours apart. The Moon and other comparatively fast-moving bodies are especially sensitive to this distinction.

Why It Matters

Recognizing the mark helps prevent timing errors when calculating a natal chart, transit, progression, or other time-dependent figure. It also matters when consulting older astrological texts, whose dating and time conventions may differ from modern software defaults. Checking whether a table is set for noon or midnight, and whether it uses local time, Universal Time, or another standard, supports a more reliable chart calculation and clearer interpretation.

Related Encyclopedia Entries

• Traditional Astrology
• Astrological Terminology
• Natal Chart
• Ephemeris
• Chart Calculation