 <span class="nowrap">r<sub>2</sub></span> be the number of days between this winter solstice and the previous lunar conjunction (i.e. the <a href="https://in-the-sky.org/article.php?term=age_of_moon" target="_blank">age of the Moon</a> of this winter solstice). The equations for N can be written as</p><p>N &equiv; R<sub>0</sub> (mod 60), &nbsp;&nbsp; <span class="nowrap">P<sub>s</sub></span>N &equiv; <span class="nowrap">r<sub>1</sub></span> (mod 60), &nbsp;&nbsp;<span class="nowrap">P<sub>s</sub></span> N