#TITLE_ALTERNATIVE#

• Main Author: SOPWAN (NIM 10303005), NOVI
• Format: Final Project
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/8841
• Institution: Institut Teknologi Bandung

In this thesis, hilal is first crescent of young Moon which can be seen by naked eyes after conjunction closed to sunset direction. Metonic cycle is a period of 235 lunation is almost equal to 19 years (tropical years). Islamic Lunation Number (ILn) is defined as moon lunation number, started with Islamic Lunation Number 1 (ILn 1) for Muharram 1H, (conjunction date of the moon on 622 July, 14), ILn 2 for Safar 1H, (conjunction date of the moon on 622 August, 12) ect. Lunation group defined through Islamic lunation variant number (ILVn) 1 through 235, so each ILn has one ILVn, ILVn 1 starts from ILn 1, Muharram 1H. Metonic hilal is hilal group with similar ILVn, or hilal borned on similar date each 19 years. On obsevation, Metonic hilal will be on similar seasonal condition and brightness caused similar Sun position in the sky on similar date. This thesis explain teoritical changes parameters Metonic hilal pattern closed to equinoxes, solstices, perihelion and aphelion. Metonic hilal parameters are Sun-Moon position differences on sunset after conjuction in equatorial, horizontal and ecliptic coordinates, hilal ages, lag time, Moon illumination fraction, Sun-Moon elongation and Moon sinodyc period. Algorithms did not guarantee that all Moon crescents were hilal, especially hilal with illumination < 0.01. Hilal knowledge with illumination < 0.01 still being studied. Generally, Metonic hilal parameters changed with unique and complex pattern. Detailed study of pattern changes in each geographical longitude and latitude is needed hilal global visibility prediction.