Sains Malaysiana 54(9)(2025):
            2263-2276
            
          
          http://doi.org/10.17576/jsm-2025-5409-13
            
          
          
             
          
          The Limitation of
            Optical Equipment in New Crescent Moon Visibility: Insight from 27 Years of
            Observation Data in Sarawak, Malaysia
            
          
          (Had Peralatan Optik dalam Kenampakan Anak
            Bulan: Pemerhatian daripada Data Cerapan 27 Tahun di Sarawak, Malaysia)
            
          
          
             
          
          AHMAD
            HARIZ BELY1, ROSLAN UMAR1,*, NOR HAZMIN SABRI2,
            AHMAD LUTFI AFIFI MOHD NASIR1, RAZALIE HUSSAINI3, EMMA
            ZULAIHA ZULKIFLI1,4, AMIRUL AKMAL REDZUAN1, ARWIN JULI
            RAKHMADI5, AMIRUL HAZIM KAMARULZAMAN1, CHE KU AHMAD FUAD
            CHE KU ABDULLAH6, NUR AZHAR AHMAD7, NUR ZULAIKHA MOHD
            AFANDI1, SHARIFAH NURUL AISYAH SYED ZAFAR1, JALALLUDIN
            BAKAR3 
  & MUSA GARBA ABDULLAHI8
  
          
          
             
          
          1East Coast Environmental Research Institute
            (ESERI), Universiti Sultan Zainal Abidin, 21300 Kuala Nerus, Terengganu,
            Malaysia 
  2Advanced Nano Materials (ANoMa) Research Group, Faculty of Science
            and Marine Environment, Universiti Malaysia Terengganu, 21030 Kuala Nerus,
            Terengganu, Malaysia
  3Bahagian Falak, Jabatan Mufti Sarawak, Lorong P. Ramlee 5, KTLD,
            93400 Kuching, 
            Sarawak, Malaysia
  4Dark Sky Malaysia, Pusat Inkubator Perniagaan, 88000 Kota
            Kinabalu, Sabah, Malaysia
  5Observatarium Ilmu Falak, Universitas Muhammadiyah Sumatera Utara,
            Glugur Darat II, Kec. Medan Tim., Kota Medan, Sumatera Utara 20238, Indonesia
  6Unit Geomatik, Jabatan Kejuruteraan Awam, Politeknik Kuching, 93050
            Kuching, Sarawak, Malaysia
  7Academy of Contemporary Islamic Studies (ACIS), Universiti
            Teknologi MARA, 94300 Kota Samarahan, 
            Sarawak, Malaysia
  8Department of Physics, Faculty of Science, Yusuf Maitama Sule
            University Kano, Nigeria
  
          
          
             
          
          Diserahkan: 16 Mac
            2025/Diterima: 25 Julai 2025
            
          
          
             
          
          Abstract
            
          
          New
            Crescent Moon visibility has been extensively studied throughout history due to
            its undeniable importance in determining the Islamic calendar. Previous
            visibility models have relied on linear statistical theory, which does not
            fully account for the circular nature of the variables involved such as
            atmospheric turbulence, light pollution and limitations of optical equipment.
            In order to address this matter, this study proposed a new visibility using the
            limitation of New Crescent Moon sighting via an optical equipment. Data were
            categorized into two visibility categories, namely: visible to the theodolite
            and potentially requiring telescopes based on the night visibility that has
            been captured. The categorization is determined based on the residual local
            data observations collected in Sarawak, spanning from 1997 to 2023. The
            proposed limitation was applied by 31 positive data from 167 observations which
            results indicate that the visibility based on moon ages and altitude of the
            moon features parameter. This study suggested that the limitation of sighting
            the New Crescent Moon using an optical equipment range between 11 and 13 h of
            moon age with a moon altitude of 5° and 6°. These new criteria have a
            significant positive impact on enhancing the likelihood of observing the New
            Crescent Moon and improving the accuracy of the Islamic calendar especially in
            Sarawak.
  
          
          
             
          
          Keywords:
            Correlation; limitation; New Crescent Moon; observation equipment; Sarawak
            
          
          
             
          
          Abstrak
            
          
          Kajian
            kenampakan Anak Bulan sangat penting dalam menentukan tarikh dalam kalendar
            Islam. Sebelum ini, parameter kenampakan Anak Bulan banyak bergantung pada
            teori statistik linear yang tidak mengambil kira faktor luaran seperti keadaan
            atmosfera, pencemaran cahaya dan keterbatasan peralatan optik. Oleh itu, kajian
            ini meneliti had kenampakan Anak Bulan dengan memberi tumpuan kepada keterbatasan
            peralatan optik dalam cerapan Anak Bulan. Data dikategorikan kepada dua jenis
            kenampakan iaitu boleh dilihat dengan theodolit dan boleh kelihatan menggunakan
            bantuan teleskop berdasarkan kenampakan. Pengelasan ini berdasarkan data
            cerapan yang dilakukan di Sarawak digumpulkan dari tahun 1997 hingga 2023.
            Limitasi yang dicadangkan menggunakan 31 data positif daripada 167 data cerapan
            bagi menentukan hubungan antara umur Anak Bulan dan altitudnya ketika
            kenampakan berlaku mengunakan peralatan. Hasil kajian menunjukkan bahawa Anak
            Bulan boleh dikesan menggunakan peralatan optik apabila usianya berada dalam
            julat 11 jam hingga 13 jam dan berada pada altitud 5 darjah dan 6 darjah.
            Penemuan ini memberikan sumbangan penting dalam meningkatkan ketepatan penentuan
            awal bulan Islam, terutamanya di Sarawak.
            
          
          
             
          
          Kata kunci: Anak
            Bulan; korelasi; limitasi; peralatan cerapan; Sarawak
            
          
          
             
          
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          *Pengarang untuk
            surat-menyurat; email: roslan@unisza.edu.my