Published By:
Hizbul Ulama UK
Central Moon Sighting Committee of Great Britain, Hizbul Ulama UK, Darul Uloom Bury, Jamiatul Ulama Britain, 74 C Upton Lane London E7 9LW - Phone No. 07866464040, 01707 652 6109, 07866 654471, 07957 205726 / e-mail : info@hizbululama.org.uk

The history of Astronomical moon calculation ,starts from 431BC(1040 years before prophet hood of beloved Prophet S.A.W.in 610CE), which copied by Abasid Khulfa after prophet (S.W.) & Khulfae Rashedin (R.A.) against ``Nasse Matlu & none matlu (Quraan & Sunnah) to conduction Islamic dates, such as Al Mansur 125h ,Harun Rashid, Mamun,  Khawarizmi, Farghani, Biruni etc
Methods for predicting
first sighting of the new crescent have been since the time of the Sumerians and efforts for criterion go back to the Babylonian era, with work done later by Jews and others. 431 BC astronomer called Meton calculated motion of planets.

The Jews and Christians used Meton`s conditioned calculation for their moon calendars. Muslims developed astronomy in the middle of 2ndcentury Hijri (between755/75 CE). Europe’s most famous astronomers were Isaac Newton, Galileo, Copernicus, Halley and Kepler in 15/16 century. Many methods for predicting lunar first visibility have been proposed throughout history and new models are still being developed.

In the twentieth century
used statistical analysis for the Moon to be first seen: 12° for Fotheringham, 11° for Maunder, 10-10.5° for Yallop and Ilyas9 , 7.5° for Fatoohi , 7°for Danjon and Schaefer, 6.4 ° for McNally5°.
These all methods including
famous "Danjon  limit" which used by Greenwich Observatory, proved  wrong by witnessing crescent (before calculated  new moon conjunction, at conjunction or immediately after it)  not only by scientists but by Muslims too .

Let we see what they says now:

Astronomer Dr. Martin Elsässer says: A recent work by Professor A. H. Sultan (Sana`a University, Yaman) predicts, the crescent could actually be seen at some conjunctions.....  It is all a matter of contrast. With increasing effort ever smaller crescents might be possible...... is no hard limit of crescent visibility at 7° or 6.5°, and definitely   not the "Danjon limit"
(Q.to Martin)  Hi Martin I am very interested in the whole theory of conjunction and how it manifests itself into the religious dimension...I am interested in > clarity on your view given below about conjunction not being a > "magical moment" as you put it. ..There have been many instances when perfectly honest people have claimed to have seen the crescent with the naked eye either just before or just after conjunction... What about sighting claims from Saudi Arabia which are often from semi desert areas with hardly any light pollution and clean air? Are these claims trustworthy...
Martin says: My experiments demonstrate that there can indeed be a crescent during conjunction...i don’t see reason to hope for a serious   breakthrough... My experiments demonstrate that there can indeed be a crescent during conjunction ... I have some ideas on how to improve the telescopes used. Possibly, the limit of what can be seen can be expanded somewhat, compared to current known results, I don’t see reason to hope for a serious breakthrough, such as required for naked eye sighting during conjunction.

Dr. Martin Elsässer also says
: I agree with Mr. Jim Stamm, that the term "Danjon limit" is being used improperly.  The moon has been recently imaged at an elongation of 4.7°. Older, space-based imaging has even gone as low as 2°. This clearly shows that "Danjon-limit" is incorrect. As the "Danjon limit" has been "broken” repeatedly by different means and as the theory behind it is incorrect we should probably stop using the term altogether.  
Astronomer Dr. Joachim Schulte in den Baumen and his team in Sonneberg Observatory(
Germany) were able to see the crescent on sat 23 rd Sep 2006 at midday13ut!(1.00pm). More surprisingly the picture was taken at broad daylight time. (Remember that sat 23 rd Sep 2006 was first day of Ramzan1427H in Saudi Arabia)
Islam and the Astronomy