src/Marando/AstroDate/AstroDate.php
public function diff(AstroDate $b)
    {
        $prec = 12;
        $jd1  = $this->toJD($prec);
        $jd2  = $b->toJD($prec);
        $days = bcsub($jd1, $jd2, $prec);

        return Time::days(-1 * $days);
    }
public function diff(AstroDate $b)
    {
        $prec = 12;
        $jd1  = $this->toJD($prec);
        $jd2  = $b->toJD($prec);
        $days = bcsub($jd1, $jd2, $prec);

        return Time::days(-1 * $days);
    }
Finds the difference between this AstroDate and another

@param  AstroDate $b

@return static