code: private BigDecimal getRightAscension(BigDecimal sunTrueLong) {
          BigDecimal tanL = new BigDecimal(Math.tan(convertDegreesToRadians(sunTrueLong).doubleValue()));
  
          BigDecimal innerParens = multiplyBy(convertRadiansToDegrees(tanL), new BigDecimal("0.91764"));
          BigDecimal rightAscension = new BigDecimal(Math.atan(convertDegreesToRadians(innerParens).doubleValue()));
          rightAscension = setScale(convertRadiansToDegrees(rightAscension));
  
          if (rightAscension.doubleValue() < 0) {
              rightAscension = rightAscension.add(BigDecimal.valueOf(360));
          } else if (rightAscension.doubleValue() > 360) {
              rightAscension = rightAscension.subtract(BigDecimal.valueOf(360));
          }
  
          BigDecimal ninety = BigDecimal.valueOf(90);
          BigDecimal longitudeQuadrant = sunTrueLong.divide(ninety, 0, RoundingMode.FLOOR);
          longitudeQuadrant = longitudeQuadrant.multiply(ninety);
  
          BigDecimal rightAscensionQuadrant = rightAscension.divide(ninety, 0, RoundingMode.FLOOR);
          rightAscensionQuadrant = rightAscensionQuadrant.multiply(ninety);
  
          BigDecimal augend = longitudeQuadrant.subtract(rightAscensionQuadrant);
          return divideBy(rightAscension.add(augend), BigDecimal.valueOf(15));
      }
docs: Computes the suns right ascension, RA in the algorithm, adjusting for the quadrant of L and turning it
  into degree-hours. Will be in the range [0,360].
  
  @param sunTrueLong
  Suns true longitude, in <code>BigDecimal</code>
  @return suns right ascension in degree-hours, in <code>BigDecimal</code> form.