Chandra Darshan

Chandra Darshan (Sanskrit: चन्द्र दर्शन, "Moon sighting") refers to the first observation of the thin crescent Moon after Amavasya (new Moon). This moment has profound significance across multiple cultures — it marks the beginning of lunar months, determines religious observances, and connects us to humanity's oldest astronomical tradition: watching the sky with the naked eye.

After each Amavasya (new Moon / conjunction), the Moon begins to move away from the Sun. For the first 12-20 hours, it remains invisible — too close to the Sun's glare. As hours pass, the Moon's elongation (angular distance from the Sun) increases, and a paper-thin crescent appears on the western horizon just after sunset. This first sighting is Chandra Darshan. The crescent is always in the west because the young Moon is never far from the Sun, and both set in the west shortly after sunset.

Whether you can see the new crescent depends on three measurable factors:

• Moon Age — Moon Age — The number of hours since the exact moment of conjunction (Sun and Moon at the same ecliptic longitude). Below ~15 hours, the crescent is essentially impossible to see with the naked eye. The record naked-eye sighting is about 15.5 hours.
• Elongation — Elongation — The angular separation between Moon and Sun, measured in degrees. Below ~7 degrees, the Moon is lost in the Sun's glare. Above 10-12 degrees, naked-eye sighting becomes feasible under good conditions.
• Altitude — Moon Altitude at Sunset — How high above the western horizon the Moon sits when the Sun sets. If the Moon has already set before the Sun, no sighting is possible. An altitude of at least 5 degrees at sunset is generally needed.

Atmospheric conditions also play a crucial role. Dust, humidity, light pollution, and clouds near the horizon can prevent sighting even when the geometric conditions are favorable. High-altitude desert locations with clean western horizons are ideal.

Astronomers have developed mathematical models to predict crescent visibility. The most widely used are the Yallop criterion (1997) and the Odeh criterion (2004). Both use a combination of Moon age, elongation, arc-of-vision (Moon's altitude minus Sun's depression), and relative azimuth to produce a visibility score. Our calculator uses a simplified version of these models that captures the essential physics while remaining computationally fast.

Hindu Tradition

In Hindu tradition, Chandra Darshan on Shukla Dwitiya (the second lunar day of the bright fortnight) is considered highly auspicious. Devotees offer arghya (water offering) to the Moon and recite prayers. The sighting is associated with Soma (the Moon deity) and is believed to bring prosperity, mental peace, and removal of sins. On specific occasions like Karva Chauth, married women observe a day-long fast and break it only after sighting the Moon through a sieve (chhalni), offering water to the Moon as a prayer for their husband's longevity.

Islamic Tradition (Hilal)

The Islamic lunar calendar (Hijri) begins each month with the confirmed sighting of the Hilal (new crescent Moon). The start of Ramadan (the fasting month), Eid al-Fitr, and Eid al-Adha all depend on Moon sighting. Islamic jurisprudence has extensive rules about who constitutes a reliable witness, how many witnesses are needed, and what happens when weather prevents sighting. Some communities now supplement visual sighting with astronomical calculations, while others insist on naked-eye observation.

Other Traditions

The Jewish calendar also historically relied on Moon sighting to declare the new month (Rosh Chodesh), though it now uses a fixed mathematical calendar. Ancient Babylonians, Egyptians, and Chinese all tracked the lunar crescent. The universal human impulse to watch for the new Moon reflects its fundamental importance to agriculture, navigation, and timekeeping throughout history.

Practical tips for your first Moon sighting:

1. Timing — Look 20-30 minutes after sunset. Earlier, and the sky is too bright. Later, and the thin crescent may have already set below the horizon.
2. Direction — Always face west, toward where the Sun set. The crescent will be slightly above and to the left (in the Northern Hemisphere) of the sunset point.
3. Horizon — Find a location with a clear, unobstructed western horizon. Hilltops, beaches, and open fields are ideal. Buildings and trees block the critical low-altitude zone.
4. Binoculars — A pair of 7x50 or 10x50 binoculars dramatically improves your chances. They can reveal a crescent invisible to the naked eye. Never use binoculars before the Sun has fully set.
5. Patience — Scan the western sky slowly. The crescent is extremely thin and can easily blend with clouds or haze. Your eyes need 5-10 minutes to adapt.

The Hindu Panchang divides each lunar month into 30 tithis (lunar days), 15 in the bright half (Shukla Paksha) and 15 in the dark half (Krishna Paksha). Amavasya is the 30th tithi — the darkest night. Shukla Pratipada (1st tithi of the bright half) begins immediately after the Sun-Moon conjunction. However, the Moon is usually not visible on Pratipada because it is still too young and too close to the Sun. Chandra Darshan typically occurs on Shukla Dwitiya (2nd tithi) or occasionally on Tritiya (3rd tithi) for locations where conditions are unfavorable.

In the Amant (Amanta) calendar system used in South and West India, the month begins after Amavasya — so Chandra Darshan effectively marks the visible start of a new month. In the Purnimant system used in North India, the month begins after Purnima (full Moon), so Chandra Darshan falls in the middle of the month, marking the transition from Krishna Paksha to Shukla Paksha.

Before telescopes and precise astronomical tables, the visual sighting of the Moon crescent was the only way to determine when a new lunar month had begun. This made Moon-watchers essential figures in ancient societies. Priests, astronomers, and designated observers would gather on hilltops to watch the western horizon after each Amavasya. Their announcement would trigger calendar changes, festival preparations, and agricultural schedules. The Surya Siddhanta and other Indian astronomical texts contain detailed rules for predicting when the Moon would first become visible — an early form of the visibility models astronomers use today.

• × "The new Moon is visible on Amavasya night" — This is incorrect. Amavasya is precisely when the Moon is NOT visible because it is conjunct with (next to) the Sun. The first crescent appears 1-2 days after Amavasya.
• × "If I can't see the Moon, it hasn't risen" — The Moon may be above the horizon but invisible due to glare, atmospheric conditions, or being too thin. Absence of sighting does not mean absence of the Moon.
• × "Chandra Darshan always happens on the same tithi" — The tithi at the time of first visibility varies by location. Western locations see the crescent earlier (same evening) than eastern locations at the same latitude.
• × "Telescopic sighting counts the same as naked-eye" — Traditions that rely on Moon sighting (Hindu, Islamic) generally require naked-eye visibility for religious purposes, though practices vary by community.