<p>From the US Naval Observatory: <a href="https://aa.usno.navy.mil/faq/crescent" rel="nofollow noreferrer">Crescent Moon Visibility</a>:</p>
<blockquote>
<p>Naked-eye sightings as early as 15.5 hours after New Moon have been reliably reported while observers with telescopes have made reliable reports as early as 12.1 hours after New Moon.</p>
</blockquote>
<p>USNO is usually a very reliable site for info like this.</p>

CC BY-SA 3.0
2016-03-22T02:45:45.423Z
- Wayfaring Stranger - That is a incredible answer, and the reference is impeccable.  Thank you very much!
elika kohen
CC BY-SA 3.0
2016-03-24T01:14:23.403Z
@barrycarter This is probably the *last* astronomy related forum upon which this question has *not* been asked.
Wayfaring Stranger
CC BY-SA 4.0
2016-03-22T02:43:56.630Z
2023-07-08T13:17:49.697Z
2023-07-08T13:17:49.697Z
Wayfaring Stranger
<h1>Question:</h1>
<blockquote>
<p>Apart from a Solar Eclipse, How much time is needed until a Waxing Crescent Moon be seen following a New Moon?</p>
</blockquote>
<ol>
<li>Would the time of year be significant? The Vernal Equinox + 1 Month.</li>
<li>Could it be seen the same night that it occurs?</li>
<li>Could it be seen in the day when it occurs?</li>
<li>Would this be affected if the viewer was in a rural location, without lights? Or would city lights help?</li>
</ol>
<h1>Context:</h1>
<p>Ancient Lunar calendars depended on observation of the New Moon, (like political / religious obligations).</p>
<p>What was the potential margin of error? Hours? a Day? (Not considering bad-weather.)</p>
<p><strong><a href="https://en.wikipedia.org/wiki/New_moon" rel="nofollow noreferrer">From Wikipedia</a> - A New Moon Cannot be Seen:</strong></p>
<blockquote>
<p>In astronomy, new moon is the first phase of the Moon, when it orbits as seen from the Earth, the moment when the Moon and the Sun have the same ecliptical longitude. The Moon is not visible at this time except when it is seen in silhouette during a solar eclipse when it is illuminated by earthshine.</p>
</blockquote>
<p><em><strong>Related:</strong></em></p>
<ul>
<li><a href="https://astronomy.stackexchange.com/questions/6072/is-it-possible-for-a-person-to-not-see-the-new-moon-at-different-places-on-earth">Is it possible for a person to not see the new moon at different places on earth?</a></li>
<li><a href="https://astronomy.stackexchange.com/questions/630/from-which-country-or-area-is-the-new-moon-visible-first?rq=1">From which country or area is the new moon visible first?</a></li>
</ul>

<observational-astronomy><time><moon-phases><the-moon>
How Soon Could a Waxing Crescent Moon Be Seen?
elika kohen
# How Soon Could a Waxing Crescent Moon Be Seen?

(Asked by: username_0 on 2016-03-21)

# Question:

> Apart from a Solar Eclipse, How much time is needed until a Waxing Crescent Moon be seen following a New Moon?

1. Would the time of year be significant? The Vernal Equinox + 1 Month.
2. Could it be seen the same night that it occurs?
3. Could it be seen in the day when it occurs?
4. Would this be affected if the viewer was in a rural location, without lights? Or would city lights help?

# Context:

Ancient Lunar calendars depended on observation of the New Moon, (like political / religious obligations).

What was the potential margin of error? Hours? a Day? (Not considering bad-weather.)

**[From Wikipedia](https://en.wikipedia.org/wiki/New_moon) - A New Moon Cannot be Seen:**

> In astronomy, new moon is the first phase of the Moon, when it orbits as seen from the Earth, the moment when the Moon and the Sun have the same ecliptical longitude. The Moon is not visible at this time except when it is seen in silhouette during a solar eclipse when it is illuminated by earthshine.

***Related:***

* [Is it possible for a person to not see the new moon at different places on earth?](https://astronomy.stackexchange.com/questions/6072/is-it-possible-for-a-person-to-not-see-the-new-moon-at-different-places-on-earth)
* [From which country or area is the new moon visible first?](https://astronomy.stackexchange.com/questions/630/from-which-country-or-area-is-the-new-moon-visible-first?rq=1)

**Tags:** observational-astronomy, time, moon-phases, the-moon


---

## 1 answers

### Answer by username_1 on 2016-03-22. Score: 5 | Accepted answer

From the US Naval Observatory: [Crescent Moon Visibility](https://aa.usno.navy.mil/faq/crescent):

> Naked-eye sightings as early as 15.5 hours after New Moon have been reliably reported while observers with telescopes have made reliable reports as early as 12.1 hours after New Moon.

USNO is usually a very reliable site for info like this.

> **Comments:**
> **username_0**: - username_1 username_1 - That is a incredible answer, and the reference is impeccable.  Thank you very much!  
> **username_1**: @barrycarter This is probably the *last* astronomy related forum upon which this question has *not* been asked.  

---

