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☽ Lunar Calendar
Live lunar phase with illumination and monthly calendar. New and full moon dates calculated with Swiss Ephemeris to ±1 minute accuracy.
Illumination comes from the Sun–Moon elongation angle: (1 − cos θ) / 2 × 100%. At New Moon (0°) illumination is 0%; at Full Moon (180°) it is 100%.
No. Moon phase is the angular gap between the Sun and Moon — identical in both systems. The ~24° Lahiri ayanamsa offset shifts the Moon's zodiac sign but not its phase angle.
Dates are calculated with Swiss Ephemeris using the Moshier analytical ephemeris, accurate to ±0.01°. The event time is narrowed by binary search to within ±1 minute.
The Moon is void of course (VOC) from its last major aspect in a sign until it enters the next sign. This window can last minutes or several hours. Traditional practice treats VOC periods as unfavorable for initiating important matters — decisions made then often require revision. The Moon changes sign roughly every 2.3 days, so VOC windows occur frequently throughout the month.
The sign colors the quality of the phase rather than its strength. A full Moon in sidereal Scorpio concentrates emotional intensity very differently than a full Moon in sidereal Taurus, even though both represent the same maximum illumination point. The phase sets the volume; the sign shapes the texture of that energy.
Each lunar cycle lasts approximately 29.5 days — the synodic month — during which the Moon travels from conjunction with the Sun to opposition and back. The cycle divides into eight phases defined by the Sun-Moon angular separation. New Moon (0°): Sun and Moon share the same ecliptic longitude. The Moon rises and sets with the Sun and is invisible from Earth. Historically the moment of beginnings; intentions planted now develop through the full cycle. Waxing Crescent (0–90°): A thin sliver of reflected light appears on the Moon's western limb. Energy is accumulative, building outward from the new seed. First Quarter (90°): The Moon is 90° ahead of the Sun — a half-circle visible in the afternoon sky. The first point of visible tension in the cycle; the moment for action and decision. Waxing Gibbous (90–180°): The illuminated face expands toward fullness, rising in mid-afternoon. Refinement and adjustment characterize this phase — the work is nearly complete but not yet revealed. Full Moon (180°): Sun and Moon are directly opposite. Maximum illumination. The Moon rises at sunset and sets at sunrise. Traditionally associated with completion, revelation, and peak emotional intensity. The exact full moon moment, pinpointed by Swiss Ephemeris, occurs at a precise second; the visual peak spans roughly three nights. Waning Gibbous (180–270°): Illumination decreases. The Moon rises after sunset and remains visible past midnight. Associated with integration — sharing and applying what the full moon revealed. Last Quarter (270°): Half-illuminated again, now on the eastern limb. Rising around midnight. Release and revision — let go of what no longer serves the next cycle. Waning Crescent (270–360°): A diminishing arc appears before dawn. The cycle closes. Rest, reflection, and clearing space for the next new beginning.
The Moon's role in magical timing runs through virtually every pre-modern esoteric tradition. Greek Magical Papyri (1st–5th century CE, now in public domain) specify which lunar phase is appropriate for each category of operation: waxing phases for acquisitive work — love, wealth, influence; waning phases for banishing, dissolution, and binding. Medieval European grimoires preserved this structure in Christian framing. The Picatrix (11th century Arabic, translated into Latin 1256) treats the Moon's phase and sign as the primary variables for any timing operation. The logic is partly astronomical: the Moon moves faster than any other point in astrology, changing sign every 2.3 days, making it the primary timing pulse of any chart. Even in Liber AL vel Legis (1904, public domain), Nuit names herself the continuous one of Heaven — a reference to the night sky the Moon traverses. Whether approached as symbolic resonance or practical timing intelligence, the eight-phase framework maps directly onto eight-pointed star symbolism found across Sumerian, Egyptian, and later Western esoteric traditions — a structural correspondence too consistent to be coincidental.
The sidereal and tropical zodiacs diverge by ~24°07′ (Lahiri ayanamsa, 2026). This shifts the Moon's sign position by approximately 24 days — if your tropical chart shows the Moon in Gemini, your sidereal Moon is likely in Taurus. The Moon's phase angle — the gap between Sun and Moon — is identical in both systems, because phase depends on their relative geometry, not on zodiac placement. What changes is the sign context: sidereal Taurus Moon reads through fixed earth qualities; tropical Gemini Moon reads through mutable air. Both describe the same sky, two different interpretive lenses. For a full comparison of what sidereal and tropical actually measure differently, see the guide to why sidereal astrology differs from tropical.
Estrevia calculates lunar phase using Swiss Ephemeris with the Moshier analytical ephemeris, accurate to ±0.01°. Phase angle is the angular difference between the Moon's and Sun's ecliptic longitudes. Exact new and full moon moments are located by binary search, narrowing to within ±1 minute. Moon sign uses the Lahiri ayanamsa (sidereal) by default; a tropical toggle is available on the chart page.
Astrology is for personal reflection and entertainment purposes only. Nothing on this site constitutes medical, financial, legal, or psychological advice. Always consult a qualified professional for decisions affecting your health, finances, or wellbeing.