A History of Astronomy

1. Introduction.- x1. The Beginnings of Islam.- x2. Islam's Reception of Foreign Science.- x3. Four Muslim Scientists.- Al-Khw?rizm?.- Al-B?r?n?.- 'Umar al-Khayy?m?.- Al-K?sh?.- x4. The Sources.- x5. The Arabic Language and Arabic Names.- The Language.- Transliterating Arabic.- Arabic Names.- Exercises.- 2. Islamic Arithmetic.- x1. The Decimal System.- x2. K?shy?r's Arithmetic.- Survey of The Arithmetic.- Addition.- Subtraction.- Multiplication.- Division.- x3. The Discovery of Decimal Fractions.- x4. Muslim Sexagesimal Arithmetic.- History of Sexagesimals.- Sexagesimal Addition and Subtraction.- Sexagesimal Multiplication.- Multiplication by Levelling.- Multiplication Tables.- Methods of Sexagesimal Multiplication.- Sexagesimal Division.- x5. Square Roots.- Obtaining Approximate Square Roots.- Justifying the Approximation.- Justifying the Fractional Part.- Justifying the Integral Part.- x6. Al-K?sh?'s Extraction of a Fifth Root.- Laying Out the Work.- The Procedure for the First Two Digits.- Justification for the Procedure.- The Remaining Procedure.- The Fractional Part of the Root.- x7. The Islamic Dimension: Problems of Inheritance.- The First Problem of Inheritance.- The Second Problem of Inheritance.- On the Calculation of Zak?t.- Exercises.- 3. Geometrical Constructions in the Islamic World.- x1. Euclidean Constructions.- x2. Greek Sources for Islamic Geometry.- x3. Apollonios' Theory of the Conics.- Symptom of the Parabola.- Symptom of the Hyperbola.- x4. Ab? Sahl on the Regular Heptagon.- Archimedes' Construction of the Regular Heptagon.- Ab? Sahl's Analysis.- First Reduction: From Heptagon to Triangle.- Second Reduction: From Triangle to Division of Line Segment.- Third Reduction: From the Divided Line Segment to Conic Sections.- x5. The Construction of the Regular Nonagon.- Verging Constructions.- Fixed Versus Moving Geometry.- Ab? Sahl's Trisection of the Angle.- x6. Construction of the Conic Sections.- Life of Ibr?h?m b. Sin?n.- Ibr?h?m b. Sin?n on the Parabola.- Ibr?h?m b. Sin?n on the Hyperbola.- x7. The Islamic Dimension: Geometry with a Rusty Compass.- Problem 1.- Problem 2.- Problem 3.- Problem 4.- Problem 5.- Exercises.- 4. Algebra in Islam.- x1. Problems About Unknown Quantities.- x2. Sources of Islamic Algebra.- x3. Al-Khw?rizm?'s Algebra.- The Name \"Algebra\".- Basic Ideas in Al-Khw?rizm?'s Algebra.- Al-Khw?rizm?'s Discussion of x2 + 21 = 10x.- x4. Thabit's Demonstration for Quadratic Equations.- Preliminaries.- Th?bit's Demonstration.- x5. Ab? K?mil on Algebra.- Similarities with al-Khw?rizm?.- Advances Beyond al-Khw?rizm?.- A Problem from Ab? K?mil.- x6. Al-Karaj?'s Arithmetization of Algebra.- Al-Samaw'al on the Law of Exponents.- Al-Samaw'al on the Division of Polynomials.- The First Example.- The Second Example.- x7. 'Umar al-Khayy?m? and the Cubic Equation.- The Background to 'Umar's Work.- 'Umar's Classification of Cubic Equations.- 'Umar's Treatment of x3 + mx = n.- Preliminaries.- The Main Discussion.- 'Umar's Discussion of the Number of Roots.- x8. The Islamic Dimension: The Algebra of Legacies.- Exercises.- 5. Trigonometry in the Islamic World.- x1. Ancient Background: The Table of Chords and the Sine.- x2. The Introduction of the Six Trigonometric Functions.- x3. Abu l-Waf?'s Proof of the Addition Theorem for Sines.- x4. Nas?r al-D?n's Proof of the Sine Law.- x5. Al-B?r?n?'s Measurement of the Earth.- x6. Trigonometric Tables: Calculation and Interpolation.- x7. Auxiliary Functions.- x8. Interpolation Procedures.- Linear Interpolation.- Ibn Y?nus' Second-Order Interpolation Scheme.- x9. Al-K?sh?'s Approximation to Sin(1 ).- Exercises.- 6. Spherics in the Islamic World.- x1. The Ancient Background.- x2. Important Circles on the Celestial Sphere.- x3. The Rising Times of the Zodiacal Signs.- x4. Stereographic Projection and the Astrolabe.- x5. Telling Time by Sun and Stars.- x6. Spherical Trigonometry in Islam.- x7. Tables for Spherical Astronomy.- x8. The Islamic Dimension: The Direction of Prayer.- Exercises.

Episodes in the Mathematics of Medieval Islam

The proliferation of science communication activities and institutions across the globe, but also the differences and similarities between countries and regions in the organisation of these activities and institutions are receiving increasing attention. This chapter considers some general issues in this process, such as the dominance of the English language. With numerous examples, it identifies and comments on some common markers of national science communication infrastructures across the world, some that are relatively stable over many years and others that are more dynamic. Five brief country case studies serve to underline the variety of international experiences and perspectives.

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Global spread of science communication: institutions and practices across continents

Kajian ini membahaskan tentang sumbangan Jamāl al-Dīn al-Qāsimī dalam bidang astronomi melalui hasil usaha beliau menulis kitab tafsir bertajuk Maḥāsin al-Ta’wīl dengan menjadikan beberapa topik astronomi yang ditekankan oleh al-Qāsimī sebagai asas kajian. Metode kajian ini berasaskan penyelidikan perpustakaan dengan menggunakan metode pengumpulan data, metode analisis kandungan dan metode kualitatif. Topik-topik terpilih telah dihuraikan dengan menggunakan analisis komparatif iaitu kajian perbandingan dengan kitab-kitab tafsir muktabar yang lain serta membawa kajian-kajian saintifik yang bersesuaian dengan topik berkenaan. Sumber data adalah melalui kitab Maḥāsin al-Ta’wīl, kitab-kitab tafsir yang muktabar, karya-karya al-Qāsimī, kitab-kitab umum, tesis dan disertasi serta laman sesawang berautoriti berkaitan dengan tajuk kajian. Hasil dapatan kajian mendapati bahawa Jamāl al-Dīn al-Qāsimī merupakan salah seorang ulama tafsir yang bersungguh-sungguh memperkasakan kekuatan pentafsiran al-Quran secara saintifik dalam sejarah Islam. Kajian terhadap karya agung beliau, kitab tafsir Maḥāsin al-Taʼwīl memberikan impak positif dalam memahami konsep tafsīr ʻilmī dengan lebih jelas terutamanya berkenaan ayat-ayat al-Kawniyyah di dalam al-Quran yang memfokuskan bidang astronomi sebagai topik perbincangan. Gabungan metode pentafsiran secara al-Ma'thūr dan al-Raʼyī yang digunakan dalam pentafsiran al-Qāsimī mengharmonikan hubungan antara inti pati al-Quran dengan kajian saintifik semasa.

Sumbangan Jamal al-Din al-Qasimi dalam bidang astronomi: Kajian berdasarkan kitab tafsir Mahasin Al Ta'wil / Hamizah Ruslan

The paper concerns the problem of integrating data from accelerometers. A suitable model of a MEMS accelerometer is presented which is a part of inertial measurement units (IMU). Such units allow to measure orientation as well as to localize systems. They also appear to be applicable for systems positioning. The main purpose of the paper is to discuss conditions that must be satisfied to calculate the location of the sensor by means of the double integration of acceleration. The model takes into account static and dynamic settings as well as the features of low-cost MEMS accelerometers. Much attention is devoted to the impact the practical motion signals from the sensor have on the desired output of integration, and simulation results emphasize the problem of determining the ‘true’ linear acceleration from accelerometer measurements.

Evaluation of position estimation based on accelerometer data

Study of sky brightness was done during night twilight and morning twilight at Teluk Kemang, Negeri Sembilan, Pantai Cahaya Bulan, Kelantan and Kuala Terengganu, Terengganu. This study was done to ensure the time for beginning and ending of astronom ical twilight are the same as the theory. Astronomical twilight is used to determine the beginning and ending of Fajr and Isha prayer time. Sky quality meter were used in this study to observe the sky brightness. The finding shows that the darkest the sky can go is to less than 20 mag per meter square in the morning (Subh) while in the night the sky can goes dark until less than 21mag per meter square. This data can be related to the sun altitude which is the condition to determine the time of beginning of Fajr and Isha prayer.

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Sky Brightness for Determination of Fajr and Isha Prayer by Using Sky Quality Meter

2 Abstract: According to fiqh, muslim prayer time of Isha' begins when shafaq ýphenomenon disappears at dusk. This research implements astronomical determinations to study the phenomenon and result the empirical descriptions. The observation was conducted at Tanjung Aru, Sabah, East Malaysia. Based on suitability, the disappearance of shafaq al-abyad is applied for Malaysia locality condition. The research has employed SQM- LE meter to col lect sky brightness data. According to the results, the sky brightness magnitude for the disappearance of shafaq al-abyad is obtained averagely at 20.79 ± 0.36 mag/arcsec with mean solar depression 2 angle at 107.99° ± 0.16°. The results are considered to be still consistent with the theoretical value of 108° which marks the beginning of night time and the disappearance of daylight.

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Astronomical Determinations for the Beginning Prayer Time of Isha

Many astronomers have studied lunar crescent visibility throughout history. Its importance is unquestionable, especially in determining the local Islamic calendar and the dates of important Islamic events. Different criteria have been used to predict the possible visibility of the crescent moon during the sighting process. However, so far, the visibility models used are based on linear statistical theory, whereas the useful variables in this study are in the circular unit. Hence, in this paper, we propose new visibility tests using the circular regression model, which will split the data into three visibility categories; visible to the unaided eye, may need optical aid and not visible. We formulate the procedure to separate the categories using the residuals of the fitted circular regression model. We apply the model on 254 observations collected at Baitul Hilal Teluk Kemang Malaysia, starting from March 2000 to date. We show that the visibility test developed based on elongation of the moon (dependent variable) and altitude of the moon (independent variable) gives the smallest misclassification rate. From the statistical analysis, we propose the elongation of the moon 7.28°, altitude of the moon of 3.33° and arc of vision of 3.74 at sunset as the new crescent visibility criteria. The new criteria have a significant impact on improving the chance of observing the crescent moon and in producing a more accurate Islamic calendar in Malaysia.

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A New Crescent Moon Visibility Criteria using Circular Regression Model: A Case Study of Teluk Kemang, Malaysia

Negara Malaysia telah menggunakan kriteria yang pelbagai dalam menyusun kalendar Hijrah. Sehingga kini kriteria imkan al-rukyah telah digunakan hampir 20 tahun. Namun, bagaimanakah proses penyusunan kriteria ini masih menjadi persoalan di kalangan ahli falak dan masyarakat awam. Justeru, kajian ini menjelaskan sejarah asal usul kriteria kenampakan anak bulan yang digunakan di Malaysia. Metode pengumpulan data yang digunakan adalah berdasarkan kajian perpustakaan dan kajian lapangan. Seterusnya, analisis induktif diaplikasikan dalam menganalisis data. Hasil kajian mendapati kriteria altitud 2 darjah dan sudut elongasi 3 darjah dirumus berdasarkan data-data kenampakan anak bulan di Indonesia. Manakala kriteria kenampakan anak bulan 8 jam setelah berlakunya ijtimak adalah berasal daripada pandangan tokoh falak Malaysia.

SEJARAH KRITERIA KENAMPAKAN ANAK BULAN DI MALAYSIA (History of the Criteria for Lunar Crescent Visibility in Malaysia)

Every celestial bodies including our Earth having their own gravity field which causing the attractive force towards the object near them. By assuming that the Earth is symmetrical sphere, the strength of the gravity field at any point on the surface of Earth should be proportional to the mass of the planet and inversely proportional to the square root of two of the distance from the center of the planet. The strength of gravitational force can be equalized with the acceleration of any mass in the influence of gravity and the value on the Earth surface, denoted as g, is approximated with standard average value g = 9.8 m/s2. Experiment conducted during two different solar eclipses, Total Solar Eclipse 2009 and Annular Solar Eclipse 2010. For 2009 experiment, the increment from pre-eclipse to the totality is about 18.92%. For the first and second set of experiment in 2010, showing the percentage increase of gravity acceleration from pre-eclipse to the annularity is about 7.51% and 8.59% respectively. This difference in gravity acceleration may cause chicken egg able to stand during the maximum phase of eclipses.

Mohd Zambri Zainuddin

Papers

Sky Brightness for Determination of Fajr and Isha Prayer by Using Sky Quality Meter

Astronomical Determinations for the Beginning Prayer Time of Isha

A New Crescent Moon Visibility Criteria using Circular Regression Model: A Case Study of Teluk Kemang, Malaysia

SEJARAH KRITERIA KENAMPAKAN ANAK BULAN DI MALAYSIA (History of the Criteria for Lunar Crescent Visibility in Malaysia)

Acceleration due to gravity changes during solar eclipse phases