scholarly journals New Moon's Visibility and International Islamic Calendar for the American Region 1407H - 1421H

1995 ◽  
Vol 12 (2) ◽  
pp. 279-284
Author(s):  
Khalid Shaukat
Keyword(s):  
Nineteenth Century ◽  
Observational Data ◽  
Brightness Contrast ◽  
Tabular Form ◽  
Mathematical Astronomy ◽  
New Moon ◽  
Friendly Competition ◽  
Late Part ◽  
American Region

The International Islamic Calendar Programme relies on calculationsof the new moon's expected visibility. The term "new moon's visibility"gives a wrong connotation, because the astronomical term "new moon"refers to a moon that is completely dark and invisible. Therefore, fromhere on the term "crescent moon" or simply "crescent" will be used for amoon that could be visible after the new moon phase.The problem of predicting the crescent moon's visibility has been ofinterest to astronomers in general for a friendly competition of sightinga young crescent moon and to Muslims for their needs associated withthe Islamic calendar. The earliest astronomical criterion for visibilityappeared in the Babylonian era: the moon's age after conjunction mustbe more than 24 hours, an arc of separation as must be more than 12° orthe moon sets 48 minutes after sunset. Hindus (500-700 C.E.) developeda more elaborate system of calculations with the same as >= 12° criterion.In the eighth to tenth centuries C.E., Muslim astronomers, notablyYa'qub ibn Tariq, Habash, al Khwarizmi, al Farghani, and al Battaniexcelled in mathematical astronomy and developed rules for predictingthe crescent's visibility based on the importance of the crescent's width.A century later, al Biruni recommended al Battani's procedures. In thefifth century, al Sufi and al Kashani still quoted the early Babylonian criterionof as >=12° .In the late part of the nineteenth century, Schmidt recorded observationsin Athens, Greece, throughout a period of twenty years. Fotheringham(1910) and Maunder (1911), who used Schmidt's data and thenadded some more observational data, made the first significant developmentsin criterion for visibility since the time of al Battani. Bruin (1977)developed an independent physics-based criterion involving such variablesas the sky's brightness, contrast, the crescent's intensity, and so on.However, his criterion was only theoretical and its validity needed to beproven by actual observations. Ilyas (1981) modified Bruin's criterion inorder to remove the discrepancy in his method and the actual observationalcriterion of Maunder. All of these suggested criteria for calculatingexpected visibility have been summarized in a tabular form on page15 ...

scholarly journals Astronomy at the service of the Islamic society

2009 ◽  
Vol 5 (S260) ◽  
pp. 514-521
Author(s):  
Ilias M. Fernini
Keyword(s):  
Proper Time ◽  
Astronomical Observatory ◽  
The Sun ◽  
The Moon ◽  
Scientific Institutions ◽  
Mathematical Astronomy ◽  
Islamic Empire ◽  
New Moon ◽  
Islamic Society

AbstractThe Islamic society has great ties to astronomy. Its main religious customs (start of the Islamic month, direction of prayer, and the five daily prayers) are all related to two main celestial objects: the Sun and the Moon. First, the start of any Islamic month is related to the actual seeing of the young crescent after the new Moon. Second, the direction of prayer, i.e., praying towards Mecca, is related to the determination of the zenith point in Mecca. Third, the proper time for the five daily prayers is related to the motion of the Sun. Everyone in the society is directly concerned by these customs. This is to say that the major impetus for the growth of Islamic astronomy came from these three main religious observances which presented an assortment of problems in mathematical astronomy. To observe these three customs, a new set of astronomical observations were needed and this helped the development of the Islamic observatory. There is a claim that it was first in Islam that the astronomical observatory came into real existence. The Islamic observatory was a product of needs and values interwoven into the Islamic society and culture. It is also considered as a true representative and an integral par of the Islamic civilisation. Since astronomy interested not only men of science, but also the rulers of the Islamic empire, several observatories have flourished. The observatories of Baghdad, Cairo, Córdoba, Toledo, Maragha, Samarqand and Istanbul acquired a worldwide reputation throughout the centuries. This paper will discuss the two most important observatories (Maragha and Samarqand) in terms of their instruments and discoveries that contributed to the establishment of these scientific institutions.

Tough Lovelies: Crotons in Queensland from the 1870s to Now

2012 ◽  
Vol 19 (1) ◽  
pp. 146-156
Author(s):  
Glenn R. Cooke
Keyword(s):  
Nineteenth Century ◽  
Leaf Shape ◽  
Drought Tolerant ◽  
The World ◽  
The Tropics ◽  
Late Part

When surveying the histories of plants under cultivation, one becomes immediately aware of the vagaries of shifting tastes. So it is with one of my favourite plants: the hardy croton, Codaieum variegatum. It was a popular hot-house plant in Europe during the nineteenth century, when colourful and variegated plants from the far corners of the world were all the rage. In the late part of the nineteenth century, these plants made their way to Australia, and were especially cultivated in Queensland. Even in sub-tropical Brisbane, plants can lose all their leaves in cold snaps during the mild winters, but further north, Queensland has a plant that can offer gardens a wide variety of colour and leaf shape. For a plant from the tropics, they are remarkably drought tolerant and have proved their resilience in both summer's heat and humidity, and our occasional extended droughts.

scholarly journals Research on Asteroids of Christian Ludwig Gerling and His Students in the Nineteenth Century

2018 ◽  
Vol 49 (1) ◽  
pp. 83-98 ◽  
Author(s):  
Julia Remchin ◽  
Andreas Schrimpf
Keyword(s):  
Nineteenth Century ◽  
Solar System ◽  
Observational Data ◽  
Minor Planet ◽  
Solar System Bodies

One of the major topics in astronomy at the beginning of the nineteenth century was the interpretation of the observations of the first asteroids. In 1810, Christian Ludwig Gerling at the age of 22 came to Göttingen University to continue his academic studies. Supervised by Carl Friedrich Gauß at the observatory, he was engaged in studies of theoretical and practical astronomy. Starting in 1812, Gerling accepted the responsibility for collecting observational data of the asteroid Vesta from the European observatories and for calculating the ephemeris of this new minor planet. In 1817, Gerling was appointed professor at Marburg University. One of his early astronomical projects in Marburg was his contribution to the Berliner Akademische Sternkarten. After completion of his observatory in 1841, Gerling’s students started observing and theoretically analysing the orbits of the continuously newly discovered asteroids including the perturbation of the larger solar system bodies. The observations at Gerling’s observatory are the first astrometric measurements of solar system’s minor bodies of Hesse.

scholarly journals Short index to reports of physical observations (electric, magnetic, meteorological, seismological) made at Kew observatory

1912 ◽  
Vol 86 (588) ◽  
pp. 358-359
Keyword(s):  
Observational Data ◽  
Annual Report ◽  
National Physical Laboratory ◽  
Magnetic Storms ◽  
Annual Reports ◽  
Tabular Form ◽  
Short List ◽  
Primary Interest ◽  
Physical Laboratory ◽  
The Subject

A summary of observational data obtained at Kew Observatory used to be given in an Annual Report, which was printed in the Royal Society's 'Proceedings' up to the year 1900. From 1901 to 1909 these data were published in the Annual Report of the National Physical Laboratory, of which Kew Observatory then formed a department. The data for 1910 have been published by the Meteorological Office, which came into occupation of the Observatory on July 1, 1910. As the Reports of the National Physical laboratory are not unlikely to be overlooked by those whose primary interest is in observational work, the Gassiot Committee decided, in October, 1911, that it was desirable that a short list of their observational contents should be published in the Royal Society's 'Proceedings.' The descriptions of the data, which appeared in tabular form in the Annual Reports, are arranged below according to the subject; when there is no specific statement to the contrary, they refer to Kew Observatory. Reference to some of the more outstanding phenomena-especially the magnetic storms–will be found in the text of the Annual Reports.

A Chinese Innovation Based on Western Methods: The Double-Epicycle Solar Model in the Lixiang kaocheng, 1722

2019 ◽  
Vol 50 (2) ◽  
pp. 174-191
Author(s):  
Guangchao Wang ◽  
Xiaochun Sun
Keyword(s):  
Observational Data ◽  
Solar Model ◽  
Solar Motion ◽  
Mathematical Astronomy

This article attempts to show how an effort was made by Chinese astronomers to improve on the solar model under the auspice of Emperor Kangxi, in circumstances of the merging of Western and Chinese mathematical astronomy. The result of this effort is the Lixiang kaocheng. Different from the eccentric solar model in the previous calendars, Lixiang kaocheng invented a double-epicycle model to describe the solar motion, aiming at bringing computations into agreement with observation. The observational data used for determining the parameters of solar model might be obtained with Tychonic instruments. But it is also possible that these “observational data” might have been derived from Western astronomical tables. Although actual observations did become more accurate, it did not reflect upon the revision of the solar model. The accuracy of the solar model in the Lixiang kaocheng did not increase very much compared with the previous models.

scholarly journals Ciprian Porumbescu, creator and protagonist of the Romanian operetta

2020 ◽  
Vol 21 (1) ◽  
pp. 36-55
Author(s):  
Rosina Caterina Filimon
Keyword(s):  
Nineteenth Century ◽  
Musical Theatre ◽  
Musical Language ◽  
School Of Music ◽  
National School ◽  
New Moon ◽  
The Creation

AbstractMusical-theatrical pieces of the nineteenth century, propagated by Italian, French and German troops, were an inspiration for Romanian composers. They will create similar fashionable musical theatre genres, in Romanian, for entertainment purposes. Works placed on the border between vaudeville and the lyrical genre can be identified in the creation of the newly emerging genre of operetta: such pieces are the compositions of Alexandru Flechtenmacher, Eduard Wachmann, Eduard Caudella. In the cultural atmosphere of the time, patriotic musician Ciprian Porumbescu (1853-1883) would find the perfect way to put a longstanding artistic wish into practice: to compose an operetta, following the success of his humorous musical-theatre pieces Cisla and Candidatul Linte [Candidate Linte]. A multifarious personality, a lover of folklore and of his nation, Ciprian Porumbescu – one of the founders of the national school of music – contributed to the authenticity and identity of the Romanian musical language through his extensive works; one important contribution is the composition of the first Romanian cultivated operetta Crai Nou [New Moon] (1882). As a tribute to his art, on the centenary of his birth, the creator of the operetta Crai nou becomes the protagonist of the operetta Lăsați-mă să cânt [Let me sing] (1954) by Gherase Dendrino, set during the time of the staging of Porumbescuʼs musical-dramatic work. Crai Nou and Lăsați-mă să cânt are highlights of the Romanian lyrical theatre, from the artistic past and present, and hold their position as musical pieces frequently performed and received with interest and enthusiasm.

scholarly journals Southern Hemisphere Observations

2002 ◽  
Vol 12 ◽  
pp. 322-325 ◽  
Author(s):  
Wayne Orchiston
Keyword(s):  
Nineteenth Century ◽  
Observational Data ◽  
Southern Hemisphere ◽  
Historical Data ◽  
Absolute Dating

AbstractBecause of insurmountable problems associated with absolute dating, the non-literate cultures of the Southern Hemisphere can contribute little to Applied Historical Astronomy, although Maori traditions document a possible supernova dating to the period 1000-1770AD. In contrast, the abundant nineteenth century solar, planetary, cometary and stellar observational data provided by Southern Hemisphere professional and amateur observatories can serve as an invaluable mine of information for present-day astronomers seeking to incorporate historical data in their investigations.

Current status of special planetary and lunar theories and ephemerides

1966 ◽  
Vol 25 ◽  
pp. 266-267
Author(s):  
R. L. Duncombe
Keyword(s):  
Observational Data ◽  
Current Status ◽  
Numerical Errors

An examination of some specialized lunar and planetary ephemerides has revealed inconsistencies in the adopted planetary masses, the presence of non-gravitational terms, and some outright numerical errors. They should be considered of temporary usefulness only, subject to subsequent amendment as required for the interpretation of observational data.

July 11, 1991 Eclipse Corona Photometry by the Results of Electropolarimetric and CCD-Matrix Observations

1994 ◽  
Vol 144 ◽  
pp. 567-569
Author(s):  
V. Kulidzanishvili ◽  
D. Georgobiani
Keyword(s):  
Solar Corona ◽  
Observational Data ◽  
Solar Limb ◽  
Ccd Matrix

AbstractThe observational data of July 11, 1991 eclipse solar corona obtained by both electropolarimeter (EP) and CCD-matrix were processed. Using these data, the solar corona photometry was carried out. The results of EP data are compared with the ones of CCD data. It must be noted here that the CCD data give us only characteristics of the inner corona, while the EP data show the features of both the inner and middle corona up to 4R⊙. Standard flattening indexϵis evaluated from both data. The dependence of the flattening index on the distance from the solar limb is investigated. The isophotes in Na and Ca lines are plotted. Based on these data some ideas and conclusions on the type of the solar corona are presented.

On The Radii of Ap Stars

1976 ◽  
Vol 32 ◽  
pp. 49-55 ◽  
Author(s):  
F.A. Catalano ◽  
G. Strazzulla
Keyword(s):  
Observational Data ◽  
Line Width ◽  
Main Sequence ◽  
Main Sequence Stars ◽  
Ap Stars

SummaryFrom the analysis of the observational data of about 100 Ap stars, the radii have been computed under the assumption that Ap are main sequence stars. Radii range from 1.4 to 4.9 solar units. These values are all compatible with the Deutsch's period versus line-width relation.

Sign in / Sign up

Export Citation Format

Share Document