(This calculator is still in the trial phase. Any issues will be refined from time to time)

KaDaR 2021 stands for Kalkulator Data Rukyah version 1.2021, which is a web calculator software for generating pre-observation data for Rukyah activities (moon and sun observation). Comparisons of the data generated with data produced by other software show differences, however, the degrees of difference is considered small for Rukyah Hilal activities. Instruments categorized as 'high magnification' are not suitable for using this data.

KaDaR 2021 generates data for use over three days at the beginning of each Hijri month, namely (1) the day before the conjunction, (2) the day the conjunction occurs, and (3) the day after the conjunction.

KaDaR 2021 does not provide information on the corresponding Hijri date, for example, the day of the conjunction could be equivalent to the 29th, 30th, or 28th day. The choice of these three days is based on the customary practice of observation according to the author's experience.

The pre-calc data generated by KaDaR 2021 is set to start 1 hour 30 minutes before sunset. This early setting allows for the activity of sun observation to be conducted before continuing with the moon/Hilal observation.

Data display explanation: