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All Journal Jurnal Matematika & Sains Spektra: Jurnal Fisika dan Aplikasinya Jurnal Pengabdian Kepada Masyarakat (JPKM)
Chatief Kunjaya
Department Of Astronomy, FMIPA, Institut Teknologi Bandung
Aerospace Engineering Agriculture, Biological Sciences & Forestry Education Electrical & Electronics Engineering Energy Engineering Materials Science & Nanotechnology Mathematics Physics Social Sciences Other

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 1 
The Temporal Variations in Sunspot Number, Geomagnetic aa index and Southern Oscillation Index Iratius Radiman; Hiroshi Miyake; Chatief Kunjaya; Yoji Takeoka; Muhamad Irfan Hakim; Zadrach L. Dupe
Jurnal Matematika & Sains Vol 7, No 1 (2002)
Publisher : Institut Teknologi Bandung

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Abstract

A study of three monthly solar-terrestrial indices of mean sunspot number, geomagnetic aa index, and Southern Oscillation Index during period of 1882 to 2000 was carried out to find any consistent short –term periodicities. We found 19, 22, and 26-month periodicities persistently occur in the above data, i nstead of 11-year pattern. We suggest that they might have solar activity origin.
On the Periodical Nature of Annual Variation of the Regressions of the Martian Polar Caps Using the Phase Dispersion Minimization-(PDM) Method Iratius Radiman; Chatief Kunjaya; Andreas Widjaja
Jurnal Matematika & Sains Vol 3, No 2 (1998)
Publisher : Institut Teknologi Bandung

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Data observations of the regressions of the Martian Polar Caps from 1905 to 1988 were reinvestigated through the Stellingwerf’s Phase Dispersion Minimization-(PDM) method. The results indicate that the annual variations of the regressions of the Martian Polar Caps is seen to have a periodical nature. The main period is found to be approximately 40 years while other periodical components of shorter duration seen in the data also exist. The shorter periods are 3, 6 and 8 years respectively. The 3 years period may be attributed to the systematic effect of 2-3 years interval in which the data was acquired. The 6 years may be a subharmonic component of the 3 years period, though it is blended. The 8 years period cannot be attributed to the same effects of observations, such as the cyclic appearances of each polar caps in the Martian epoch of observations. Irregularity of the epoch interval of observations prevent such a systematic effect to be seen. Therefore, we like to point out that the 8-years period is a real physical phenomenon of the annual variations of the polar regressions. This strongly support the findings of Iwasaki and Ebisawa on sizes of the South Polar Cap. The PDM-method is sufficiently general to analyze small sets of data involving missing observations and non-sinusoidal time variations. The method was used to ascertain results obtained previously through time-series calculations which involved missing observations. Discussions on probable relations between changes in solar radiation which might affect the annual regressions of the polar caps are also examined.
Patrol Observation of the Southern Dwarf Novae at The Bosscha Observatory Chatief Kunjaya
Jurnal Matematika & Sains Vol 5, No 2 (2000)
Publisher : Institut Teknologi Bandung

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STUDI APLIKASI METODE POTENSIOMETRI PADA PENENTUAN KANDUNGAN KARBON ORGANIK TOTAL TANAH  The result of patrol observation of dwarf novae at the Bosscha Observatory are presented. The images of the region of four dwarf novae, MM Scorpii, V2051 Ophiuci, V391 Scuti and V3462 Sagitarii could be taken. MM Scorpii and V391 Scuti were not detectable implying quiescence state. The eclipsing SU UMa type dwarf nova, V2051 Ophiuci was observed during its outburst. Brightness measurement using aperture photometry method yields (15.2 ± 0.3) mag. V3462 Sagitarii were also detectable and the brightness (15.3 ± 0.6) mag were derived. Therefore this star is suspected in its outburst state during the observation.
Solar Cycle Variations and its Effects on El Niño/La Niña Behaviour Iratius Radiman; Dhani Herdiwidjaja; Zadrach L. Dupe; Chatief Kunjaya; Muhammad Irfan Hakim
Jurnal Matematika & Sains Vol 8, No 2 (2003)
Publisher : Institut Teknologi Bandung

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Variations in the Solar Cycle has been known for a long time. The Solar Cycle is observed to vary from 14 to 8 years in length. The reconstructions of the annual solar total irradiance since the beginning of Maunder Minimum (from year 1600) to year 2000 show that there are envelopes of groups sunspot numbers. The intensities delineated by the envelopes are consistent with the range of CaII brightness. The timelength of the envelopes corresponds to long term variabilities such as the Gleissberg Cycle of 88 and 124 years period. A close correlation between total irradiance and sunspot number from 1610 to 2000 is found to be 0.88. Although the work of Labitzke and van Loon has clearly shown the existence of an oscillation in many atmospheric parameters with a period in the vicinity of 11 years and a phase that is related to that of solar activity, there is reluctance to accept a relationship to the 11-year solar cycle. Therefore this study aimed to pursue the investigations further by determining the correlation coefficients to lower trophospheric layers. Our studies reveal to results, which we summarized as follows: A weak correlation at 27 month delay is found between solar activities and the El Niño/La Niña phenomena. The next El Niño/La Niña event is expected to occur from year 2002 until mid 2003. A major change in the pattern of the solar cycle since 1700 appears. The sun is seen to be more frequent in its active states over the last 100 years. The length of the cycle is becoming shorter. The solar cycles modulate from 5, 8, 12 and 25-year period obtained from its total irradiance plot. The 5-year period coincides very well within the El Niño/La Niña period of 2 to 7-year. The El Niño/La Niña phenomenon has a 10-12 month duration. Every El Niño/La Niña event is separated from 24 to 84 months duration in an irregular pattern. Every El Niño/La Niña event is unique. These conclusions are drawn after decomposing the SST Anomaly Index through applied Fourier Transform. The effect of the solar cycle variations is to generate long period harmonics in the coming El Niño/La Niña events. We expect that more variability in climate will occur in the coming decade.
Are El Ninõ and La Nina Phenomena Influenced by Solar Activities ? Chatief Kunjaya; Iratius Radiman; Zadrach Dupe; Dhani Herdiwidjaja; M. Irfan Hakim
Jurnal Matematika & Sains Vol 6, No 1 (2001)
Publisher : Institut Teknologi Bandung

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Abstract

El Ninõ and La Nina phenomena have caused disasters in many countries. Many million dollar losses has suffered by millions of people in several regions. However the exact cause of the phenomena is still unclear. The Sun plays the central role in determining the earth climate, therefore it is reasonable to think that changes in the Sun behaviour may influence the climate on earth including the El Ninõ and La Nina phenomena. Based on this consideration we tried to find any relationship between the indicator of solar activity, i.e. sunspots, and the indicator of El Ninõ and La Nina phenomena, i.e. Southern Oscilation Index (SOI).
PELATIHAN PEMANDU ASTROWISATA DAN PENCARIAN LOKASI PENGAMATAN DALAM RANGKA PERSIAPAN MENGHADAPI GERHANA MATAHARI 202 Chatief Kunjaya; Zadrach Ledoufij Dupe; Edi Riawan; Rahel Drupadi Chandepanembrama; Fachri Andeaf Ramadhan; Nida Azkiya; Mohammad Fa’iq Tarikh
Jurnal Pengabdian Kepada Masyarakat Vol 3 No 1 (2023): Juni 2023
Publisher : Universitas Nusa Cendana

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Abstract

Pulau Sabu merupakan daerah yang memiliki jumlah hari cerah yang terbanyak di Indonesia dengan langit yang bersih minim polusi cahaya. Di lokasi seperti itu sangat baik untuk dikembangkan astrowisata, karena harapan cuaca cerahnya tinggi sehingga harapan suksesnya penyelenggaraan suatu event astrowisata juga tinggi. Gerhana Matahari 20 April 2023 yang melalui wilayah Indonesia Timur merupakan suatu fenomena yang dapat dimanfaatkan untuk membuat event astrowisata. Untuk mempersiapkan event tersebut dilaksanakanlah pelatihan bagi calon pemandu wisata dan pencarian lokasi terbaik untuk menyelenggarakan event pengamatan gerhana matahari untuk turis dan masyarakat setempat. Tujuan pelatihan calon pemandu itu adalah agar pulau Sabu memiliki orang-orang yang cukup mampu mendampingi masyarakat dan wisatawan dalam mengamati gerhana matahari dengan cara yang baik dan aman. Pemilihan lokasi diperlukan agar masyarakat dan wisatawan dalam jumlah cukup banyak dapat mengamati gerhana bersama-sama di tempat yang memiliki medan dan arah pandang yang baik ke arah Matahari selama gerhana berlangsung. Pelatihan telah dilaksanakan dengan peserta para siswa sekolah menengah, guru dan staf dinas pariwisata kabupaten Sabu Raijua. Dari beberapa lokasi yang disurvey, diperoleh lokasi terbaik pengamatan Gerhana Matahari adalah taman doa Skyber.
Magnitude Transformation from RGB Bayer Filter to the Johnson-Cousins BVR Filter Based on CAT-ITB Telescope Photometric Observations of Selected Open Clusters Raihan Amirul Husana; Mahasena Putra; Anton Timur Jaelani; Chatief Kunjaya; Aliyya Nur Rahma; Firdaus Orvin Dwifauja Manalu
Spektra: Jurnal Fisika dan Aplikasinya Vol. 11 No. 2 (2026): SPEKTRA: Jurnal Fisika dan Aplikasinya, Volume 11 Issue 2, August 2026
Publisher : Program Studi Fisika Universitas Negeri Jakarta

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.21009/SPEKTRA.112.05

Abstract

Photometry is one of the astronomical measurement methods that provides astronomers with information about the brightness of astronomical objects at various wavelengths. Over time, various photometric systems have been developed. Therefore, transformations are necessary to convert results from one photometric system to another, with the aim of facilitating scientific communication among researchers working with various photometric systems. The CAT-ITB, or City Astronomical Telescope ITB, is an 11-inch optical telescope located at CAS ITB, equipped with detectors, one of which is the ZWO ASI 183MC that uses the RGB Bayer filter. Hence, transformation equations from the RGB Bayer filter system to the Johnson-Cousins BVR filter system must be established. By utilizing transformation equations that have historically been widely used by previous researchers, this study focuses on deriving the coefficients needed to solve those equations. Observational data of open clusters M67, RU 135, IC 4665, and M11 were obtained using CAT-ITB, which were used to optimize the transformation equations. The coefficients derived from M67 photometric data yielded the best results. The total RMS values for the magnitude transformations of clusters M67, RU 135, IC 4665, and M11 in each of the BJohnson, VJohnson, and RCousins conversions are 0.296, 0.152, and 0.161 respectively. All transformations produced small residuals and colour-magnitude diagrams that closely resemble those from catalog data. This study contributes a validated set of transformation coefficients and zero-point constants specific to the CAT-ITB RGB Bayer detector system, offering a practical reference for converting RGB-based photometric observations into the standard Johnson-Cousins system for future small-telescope and citizen-science photometric research.
Co-Authors Aliyya Nur Rahma Andreas Widjaja Anton Timur Jaelani Dhani Herdiwidjaja Edi Riawan, Edi Fachri Andeaf Ramadhan Firdaus Orvin Dwifauja Manalu Hiroshi Miyake Iratius Radiman M. Irfan Hakim Mahasena Putra Mohammad Fa’iq Tarikh Muhamad Irfan Hakim Nida Azkiya Rahel Drupadi Chandepanembrama Raihan Amirul Husana Yoji Takeoka Zadrach Dupe Zadrach L. Dupe Zadrach Ledoufij Dupe