Postmarked Thu Feb 18 06:07:17 1993 From: Mohib.N.Durrani Cc: mnd@cunixb.cc.columbia.edu Subject: *** HINTS: CRESCENT MOON SIGHTING *** Bismillah hir-Rahman nir-Rahim ( I begin with the name of Allah, the Most Beneficent, the Most Merciful ) THE MUSLIM STUDENTS' ASSOCIATION (MSA) of COLUMBIA UNIVERSITY 102 Earl Hall, Columbia University, NEW YORK, N.Y. 10027 HILAL (CRESCENT MOON) SIGHTINGS ******************************* Dr. Mohibullah N. DURRANI, Syed Zafaruddin Sayeed. Muslim Students Association Islamic Amateur Astronomers Association 102 Earl Hall, Columbia University NEW YORK, N.Y. 10027 Email to: mnd@cunixb.cc.columbia.edu (Mohib.N.Durrani) *************************************************************************** SOME INFO ON LUNAR SIGHTINGS **************************** CONTENTS: A. Youngest Naked-Eye Crescent Moon Sighting B. Crescent Moon Sighting Survey C. Direction for Kabah D. Lunar Orbit: 1. The SUN 2. The EARTH 3. The MOON 4. ATMOSPHERIC Optics 5. HUMAN Optics 6. International DATE-LINE (SOLAR) 7. International LUNAR DATE-LINE 8. ISLAMIC Considerations 9. Information on CRESCENT MOON SIGHTINGS and HINTS 10. APPARANT SIGHTINGS, HONEST and SINCERE MISTAKES 11. References 12. Figures *************************************************************************** A. WORLD RECORD: "THE YOUNGEST NAKED-EYE CRESCENT MOON SIGHTING" "THE BADAT & AL-THANI SIGHTING" ***************************** Ref: Royal Astronomical Society of Canada, Vol 83/3, Pages 34-36 Newsletter/Bulletin, June 1989 The YOUNGEST naked-eye CRESCENT MOON of 13 hours and 24 minutes was sighted on Friday 5 May 1989 at Houston, Texas, USA by two separate groups of people thus making a NEW WORLD RECORD. The previous record was of 14 hours and 30 minutes on 2 May 1916 at Scarborough, Yorkshire, England. The first of the two groups consisted of FIVE people who sighted the Crescent Moon and the second of the two groups, located at a different place, comprised of THREE people. The first group who sighted the Crescent Moon consisted of the BADAT family: Mr. Mohammed Iqbal Badat, Mrs. Famida Iqbal Badat, Mr. Mohammed Hanif Badat, Mr. Abdul Qadir Badat, and Miss Fatima Badat. The second group comprised of Mr. Saleh Al-Thani, Mr. Nasir Al-Qaouq, and Mr. Aymen Qadorah. This Crescent Moon sighting will henceforth be refered to as the BADAT AND AL-THANI SIGHTING. *************************** **************************************************************************** *************************************************************************** B. SUBJECT: CRESCENT MOON: FIRST VISIBILITY (every lunar month) *************************************************************** (*) Hilal (crescent) sightings would be in the evenings, at least 10 minutes after sunset, usually before 20 minutes, and upto 40 to 90 minutes after sunset; near and along the sun's path. We are conducting research/survey on the recorded WORLD-WIDE first sightings of the "CRESCENT MOON, FIRST VISIBILITY" in the evenings, for every lunar month. Some TECHNICAL INFO. is at the end. PHOTOGRAPHS / SLIDES ARE MOST WELCOME since they are very helpful in the research. Please also pass on the request to your friends who are interested in astronomy/physics and to your local amateur astronomy associations. We would very much like to hear from you. Please respond either by email or by letter. The survey results are to enhance the present ATMOSPHERIC MODEL and fine tune some parameters regarding SCATTERING/VISION. When reporting actual Crescent-Hilal sightings, (even if you do not see it) PLEASE INCLUDE THE FOLLOWING: HILAL was visible to naked eye?......... Hilal sighted in binoculars?........ EXACT TIMES: Complete Sunset at......... Hilal First Visible....... End...... HEIGHT-Degrees: Hilal highest........... Hilal lowest (faded/set)............ ORIENTATION: Ends of Hilal Curve: Start at......'O Clock:End at.....'O Clock (Right is 3'O Clock:Bottom is 6'O Clock: Left is 9'O Clock:Top is 12'O Clock) WEATHER condition: Rel.Humidity......... Temperature..... Pressure........... Sky near western horizon: Clear?........ Hazy?........... Cloudy?............ OBSERVER: Age.... Eyesight: Glasses?.... Far sighted?.... Near sighted?...... Name....................... Date........ Location............................ **************************************************************************** C. APPROXIMATIONS TO DIRECTION OF KA'BA (MAKKAH Saudi Arabia) ************************************************************* In most places of the UNITED STATES of AMERICA, an APPROXIMATION to the direction of KA'BA, to determine the DIRECTION OF SALAT (PRAYERS), can be obtained by noting the direction of your SHADOW near the time of SUNSET. The direction in which your shadow goes is usually a little north of east DURING WINTER. This is the direction in which salat can be performed, as an approximation. This direction of the shadow changes during the different months of the year but is a good approximation when there is no magnetic compass to determine the exact direction. During summer, the shadow goes south of east and hence we would have to turn further north from the shadow, ie. further to the left of the evening shadow. For locations in the West of America the direction is even further North from the shadow, ie. even further to the left of the shadow. **************************************************************************** **************************************************************************** D. LUNAR ORBIT ETC. ******************* The following is a brief explanation for the Lunar Orbit and its effects on HILAL (crescent) sightings. (Because of the brevity, some of the terms have been stated approximately.) 1. THE SUN The Sun seems to go around the earth (when our coordinate system is centered at our individual location on the surface of the earth) due to the earth's ROTATION about its axis. The rate of rotation of the earth about its axis is about 360 degrees in 24 hours, i.e. 4 minutes for 1 degree of rotation. This daily rotation of the earth causes night and day. 2. THE EARTH In addition to rotation, the earth REVOLVES about the sun at a rate of about one revolution in one year. This annual revolution of the earth causes the seasons. There is actually another reason for the seasons. The axis of rotation of the earth about itself is inclined to the plane of revolution of the earth about the sun, the axis is not perpendicular to the plane of revolution. The inclination of the axis of rotation of the earth is about 23-1/4 degrees from the perpendicular to the plane of revolution of the earth about the sun. This is the reason for the Tropics of Cancer and Capricorn being at 23-1/4 degrees North and South of the Equator, respectively. The Arctic Circle and the Antartic Circle are the same 23-1/4 degrees from the North Pole and the South Pole, respectively. This plane of revolution formed by the elliptic path of the earth around the sun is called the ECLIPTIC. The inclination of the axis of rotation of the earth on its axis to the plane of revolution of the earth around the sun (this inclination is approximately fixed in space) causes the different hemishperes (north and south) of the earth to face the sun more directly at different times in a year and hence collect more solar energy during those months. Hence summers are around July in the northern hemesphere and are during January in the southern hemisphere. While there is summer in the northern hemisphere there is winter in the southern hemisphere. This inclination is also the reason for `days' of 6 months, `nights' of 6 months and for the occasion of the `midnight-sun' in the polar regions. 3. THE MOON The Moon revolves around the earth in a plane only slightly inclined to the Ecliptic, about 5 degrees. Hence the Crescent Moon is visible close to the daily path of the setting Sun (max. 5 deg. above or below the Sun's path). The following procedure can be used to approximately measure angles in the sky: when you stretch out your hand in front of you and keep your four fingers together (ie. not spread out) then the four fingers of your outstretched hand make an angle of approximately 6 degrees at your eye. The yearly path of the Sun - relative to the earth - is the ECLIPTIC. The Moon always points approximately the same side to Earth, even when the moon is crescent or full. The slight vibrations of the moon about its mean pointing direction towards the earth is called LIBRATION. Libration angle is less than approximately 10 degrees in the North-South or in the East-West directions of moon-pointing- to-earth vector. Librations are considered in the CRESCENT VISIBILITY model since different parts of the edge of the moon would form the crescent at different months. The moon has also to be beyond a certain minimum angular seperation from the sun - as viewed by an observer on the earth's surface - for the crescent to be sufficiently illuminated so that the crescent may be visible. This angular separation of the moon from the sun (elongation) is indicated approximately by the AGE OF THE MOON, since its birth (the `new moon'), for the particular lunar month (lunation). The minumum recorded age of the crescent moon for first visibility is around 13 1/2 hours. For a terestrial observer, the moon aparently revolves slower than the sun around the earth (about 1/2 deg.per hour slower) and hence the moon sets at a later time every day as compared to the sunset time. (Relative average retardation of the moon is 1/2 deg/hr = 12 deg/day) Time for one Rotation (360deg) is 24 Hr x 60 min. Hence time to makeup the additional 12 deg rotation = 12 x 24x60/360 = 48 min. This is the average daily delay in moonsets. This quantity varies considerably in latitudes far from the equator. There are many other factors that are not being mentioned, at present, since they are being investigated theoretically and emperically, and have not yet been quantified accurately. Some of these additional factors are the inclination of the Lunar path to the horizon and hence the vision contrast between the crescent and the colored, bright twilight sky, the reflectance of different parts of the lunar surface (moonlight is ofcourse only reflected sunlight), the moon-earth and the moon-sun distances, lunar librations, etc. 4. ATMOSPHERIC OPTICS The atmosphere is neither completely transparent nor is it `colorless'. The aerosols, water-vapor, dust and other particles - of different sizes and at various altitudes - form the phenomena of `Blue Sky', red twilights etc. The optics of scattering, dispersion, diffusion, polarization, absorption etc. interact with each other to give the integrated color and brightness of twilight - which changes with time, location in the sky, and the amount of particulates in the environment. Meterological information averaged over many years and estimated for different terestrial locations and time of the year give average conditions which are further refined based on short term forcasts. The atmospheric pressure can be determined from a barometer and the relative humidity (RH) from an RH instrument or from the dry & wet bulb temperatures. An easier way would be to see the local newspaper giving the info for that particular day or the local meteorological department can give the info on Atmospheric Pressure, Relative Humidity and Temperature. 5. HUMAN OPTICS The human eye has characteristics of pupil size, night adaptation, visual acuity of contrast etc. Physiological studies corelate the reduction of pupil size with age of observer, sharper visual acuity for females (as compared to males), and generally better vision in children than in adults. 6. INTERNATIONAL DATE-LINE (SOLAR) The International Date-line corresponds approximately with the 180 degree meridian and it is where the calendar dates are separated. The date is advanced by one day when crossing this 180 deg meridian in a westerly direction (from east to west, across the imaginary line) and the date is set back by one day when crossing it in an easterly direction (from west to east, across this imaginary line). 7. INTERNATIONAL LUNAR DATE-LINE In recent times, the Malaysian Astronomer (with the sub-continent background of Aligarh Muslim University) Muhammad Ilyas, has been the first to propose an International Lunar Date-line (ILD). This line is actually those places where the crescent moon is first visible for any particular lunar month. It is in the refining of the range of `thickness' of this line that most of the research for crescent observations is being done. In America, muslim astronomers and amateur astronomers like Dr. Kamal Abdali, Dr. Umar Afzal, Dr. Imad Ahmad, Dr. Rauf Imam, Dr. Mohibullah N. Durrani, Profs. Fakhraddine Karray, Ali Kyrale, Charles Evans, Syed Zafaruddin Sayeed, etc. have contributed both to the analytical calculations and to the dissemination of astro-information and consciousness to muslims. Dr. Kamal Abdali has also prepared the PRAYER TIMES book for many cities in America (published by ISNA) as far back as 1978. The first major CRESCENT SIGHTING seminar held in USA was probably the one of August 1985, organized in New York by Br. Syed Zafaruddin Sayeed and Dr. Umar Afzal, in which Dr. Kamal Abdali had presented computer plots of predicted lunar sighting curves, overlaid on a world map. The next major seminar in USA was organized by the International Institute of Islamic Thought, Reston, Va. Tel (703) 471-1133 in June 1987. The Malaysian astronomer, Muhammad Ilyas, was the keynote speaker. There were other speakers - astronomers, amateurs, from the U.S. Naval Observatory in Washington, NASA - Islamic scholars, who presented the current islamic views. This was followed by the third seminar organized by Br. Syed Zafar Sayeed and Dr. Umar Afzal in New York on June 1988, further elaborating recent findings. A lecture was also presented at the 15th Annual Convention of the Association of Muslim Scientists and Engineers (ASME) on October 1989 by Dr. Mohib Durrani and Br. Syed Zafaruddin Sayeed. 8. ISLAMIC CONSIDERATIONS The Fiqh Council of North America (ISNA) states (April 1988): " ... Criteria for determining the beginning and end of Ramadan. ... The Fiqh Council, after deliberation and review of the past criteria, fiqh opinions, and contemporary positions of Muslim scholars in North America and in the Muslim world, has decided to follow the authentic, well-founded, and widely accepted position of IKHTILAAF AL-MATAALI (literally, different horizons or different places of sighting), which states that each locality should make its own sighting of the crescent. The Fiqh Council, therefore, has concluded that North America should be considered as one MATLA (place of sighting) and that Muslims of North America should depend solely on crescent sightings in North America. ... The Fiqh Council also concluded that the date for the Eid al-Adha will coincide with the date announced in MECCA for the day of Eid al-Adha." The Fiqh Council of North America (ISNA) states (March 1989): " ... Based on our decision of last year to follow the fiqh position of IKHTILAF AL-MATAALI (depending on moon sightings within your region), the Fiqh Council will depend only upon the physical sighting of the crescent in North America to determine the beginning and end of Ramadan. ... " 9. INFORMATION ON CRESCENT MOON SIGHTINGS AND HINTS On an evening previous to the Moon Sighting evening, it is advisable to find a place with a clear Western Horizon (i.e. without any buildings or trees obstructing the place where the sun sets on the western horizon). Observe and note down the approximate angle of inclination of the PATH OF THE SUN while it is setting. This inclination of the path of the setting sun from the vertical is nearly equal to the latitude of the observing location. TO SEEK THE CRESCENT MOON. In order to obtain an idea as to approximately where to look, the following information on lunar orbit is useful. The PATH OF THE CRESCENT MOON while it is setting will be nearly parallel to the path of the setting Sun. The path of the Moon will be CLOSE to the path of setting Sun, being at a maximum of about 5 degrees (usually it is less than the +/- 5 deg) `above' or `below' the path of the sun, when observed from the surface of the earth. (See Figure 12A.) The Crescent Moon will also be TRAILING the Sun by about 5 to 20 degrees, for a particular observing point. The earliest sightings in the world would have the moon trailing the sun by the least angle. The Trailing angle of the Moon from the Sun can be estimated from the Orbital details and the location of the observer. The DURATION of the first sightings of very young moons may begin as early as 10 minutes after the sun has set (to allow the twilight to reduce in spectral intensity) with the first sightings being usually before 20 minutes after sunset and the sighting could continue for about 40 to 90 or more minutes after sunset. The sighting would finally be `fading' when the crescent is a few degrees above the horizon. The fading is due to atmospheric extinction caused by absorption. In order to isolate the Crescent from twilight glare it is helpful to have any hollow tube and to search for the crescent while looking through the tube. (See Figure 12B.) The HORNS OF THE CRESCENT MOON (i.e. the ends of the approximately less than semi-circular arc of the Crescent) will always point in a direction approximately opposite to the location of the sun, the sun already being below the horizon. (See Figure 12C.) A general rule for MEASURING ANGLES in the sky is as follows: When our hand is stretched out in front of us (hand facing the sky) a. each finger at arm's length would cover about 1.5 deg at our eye, b. two fingers " 3.0 deg " c. four fingers " 6.0 deg " d. closed fist " 10.0 deg " e. outstretched fingers " 20.0 deg ". (See Figure 12D.) 10. `APPARANT SIGHTINGS', HONEST AND SINCERE `MISTAKES': Of course, the Crescent Moon has to set and not appear to `rise' in the western horizon. A WISP OF CLOUD, which happened to be lit by the sun which has already set, could easily be mistaken for a crescent. This apparant `crescent' of cloud would travel with the prevailing winds and would not set in a path nearly parallel to the path of the setting sun. It could `rise' instead of set or may travel north-east or south-east insted of setting in the west. REFLECTIONS from high-flying aeroplanes. These reflections of the sun on aeroplanes would not have the semi-circular arced shape of the crescent and the probability of their path being close to a lunar path is minute. The reflections could disappear while still being high up on the horizon. MOMENTARY VISIBILITY of the crescent. It might appear that the crescent was `visible' for a moment by a single Shahid (witness). A crescent would always be visible for at least 5 minutes (if unobstructed by clouds, etc.) and hence should be again visible by the person first seeing it, and should be able to be seen by others in a group, when pointed out. All should examine the crescent carefully and try to ascertain its path and the direction of its horns. A note should be made of the time of sunset, time (and vertical angular height = altitude) when the crescent was first visible and again the time (and vertical angular height = altitude) when the crescent faded away near the horizon. The vertical angular distance, which is the altitude of any heavenly body, is measured from the horizon. 11. REFERENCES: Some books that deal with muslim contributions to Math and especialy astronomy are the following: ISLAMIC CALENDAR, TIMES & QIBLA Muhammad Ilyas, 1984, 256 pages Berita Publishers, Malaysia. (ISBN: 967-969-009-1) ASTRONOMY OF ISLAMIC TIMES FOR THE TWENTY-FIRST CENTURY Muhammad Ilyas, 1989, 254 pages Mansell Publishers, London MUSLIM CONTRIBUTION TO CIVILIZATION H.Bammate, 1962, 62 pages Islamic Center, Geneva STUDIES IN THE ISLAMIC EXACT SCIENCES E.S.Kennedy, 1983, 771 pages American University of Beirut ISLAMIC MATHEMATICAL ASTRONOMY D.A.King, 1986, 233 pages Variorum Reprints Some books that deal with astronomy are the following: ASTRONOMICAL PHENOMENA (for each year, avalilable a year in advanve) Prepared by: The Nautical Almanac Office United States Naval Observatory U.S. Government Printing Press TEXTBOOK on SPHERICAL ASTRONOMY W.M.Smart, R.M.Green, 6th Ed, 1977 Cambridge University Press 12. FIGURES: ************ 12A. PATH OF THE MOON RELATIVE TO THE PATH OF THE SUN ***************************************************** (THIS DIAGRAM IS FOR A TYPICAL PLACE IN THE NORTHERN HEMI-SPHERE, IN THE SOUTHERN HEMI-SPHERE, THE PATH SLOPES DOWN AND LEFT.) \ \ --> \ \ <--------- Max. angular separation \ \ +/- 5 deg (moon-sun paths) \ \ P \ \ A \ \ T \ \ H P \ \ A \ \ T \ (( CRESCENT (HILAL) H \ (( MOON -------------------------------- \ \\ // ^ O \ == (if moon's path is | F \ `above' sun's path) | \ | S \ | \ O U \ | \ F A N \ | \ L \ | \ M T. /\ \ O // \ \ O D (90 - LATITUDE) =~ ANGLE of \ \ N I (= COLATITUDE) Inclination | \ \ F // | \ \ F. ========================= \ ================================ WESTERN | \ HORIZON | | \ | | | | \/ SUN v | --(@@)-- -------------------------- | /\ SUN | (has already set) | | | ----->| |<----- | AZIMUTH | DIFFERENCE BETWEEN THE MOON & SUN 12B. ALTITUDE OF MOON AT SUNSET ******************************* ) )) CRESCENT )) MOON )) ) / / / / / /\ Angle of Height of Moon, / \ = Altitude of Moon ( ) ----------------------------------------- \/ SUN | / HORIZON - HORIZONTAL --(@@)-- |/ /\ SUN |----- (has just set) | | / \ / \ ______________________________________________________ ////////////////////////////////////////////////////// GROUND GROUND GROUND GROUND GROUND GROUND GROUND Height (degrees) of first sighting: Height (degrees) of last sighting (fading) or moonset: The heights (altitudes) of the crescent are to be noted not only when it is first sighted, but also when it fades while it is going lower in the sky, since the crescent could sometimes fade away - due to atmospheric opacity - even before it sets in the western horizon. 12C. ORIENTATION OF ENDS OF CRESCENT ************************************ AND ITS CURVATURE The orientation of the Crescent is reported with reference to an imaginary clock on the western horizon: IMAGINARY CLOCK ON WESTERN HORIZON 12 'O Clock | ___ ( ) 9 'O Clock -- ( ) -- 3 'O Clock (( )) __ HILAL (Crescent) === Shown from 4 through 6 | to 8'O Clock position 6 'O Clock CRESCENT 1: CRESCENT 2: CRESCENT 3: ( ) ( ) ( ( ) ) ( __ __ ) == From: 7 'O Clock From: 4 'O Clock From: 2 'O Clock To: 10 'O Clock To: 8 'O Clock To: 5 'O Clock Note: The Crescent orientations could be anywhere from around the 2 'O Clock position to the 10 'O Clock positions. The actual extent(length) of the crescent would usually be less than 180 degrees, i.e. 2-7 (this would be 150 deg), 3-9 (this would be 180 deg), 4-9:30 (this would be 165 deg), 5-9:30 (this would be 135 deg) etc. 12D. MEASURING APPROXIMATE ANGLES IN THE SKY ******************************************** a. each finger at arm's length would cover about 1.5 deg at our eye, b. two fingers " 3.0 deg " c. four fingers " 6.0 deg " d. closed fist " 10.0 deg " e. outstretched fingers " 20.0 deg ". (See Figure 12D.) --->| |<--- 1.5 deg for each finger. ( ) | | | |----------- | | | / \ / \ ______________________________________________________ No.of Fingers: 2 fingers 4 fingers 4 outstretched fingers and Angle 3.0 deg 6.0 deg 20.0 deg thumb Distance -->| |<-- -->| |<-- -->| |<-- Fingers >> || |||| __\||/ Palm >> || || || Wrist >> ---- ---- ---- **************************************************************************** Copyright Dr.M.N.Durrani, 1987 to 1993 Permission to copy for free distribution is granted to all, please do give credit and reference. Thanks. For further information, please feel free to contact: Mail: Dr.Mohib.N.Durrani Islamic Amateur Astronomers Association (Research Division) 601 West 113 Street, Suite 11-K Columbia University NEW YORK, N.Y. 10025 United States of America Email to: mnd@cunixb.cc.columbia.edu (Mohib.N.Durrani) ***************************** End of Document ******************************