Abdul Ahad
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Abdul Ahad, (1968 - ) Astronomer and Space Science Researcher.
Abdul Ahad was born in the Sylhet district of Bangladesh on 15 December 1968. When he was 9 years old he moved to the UK. In January 2002, he founded the AA Institute of Space Science & Technology, a conceptual research institute dedicated to his own creative works and research projects. He has since undertaken a NASA-inspired program of self funded, self initiated pursuits in areas like rocketry and aerospace and remote sensing via tele-robotics.
In August 2002, he joined the California-based Planetary Society to further his participation in and outspoken advocation of global space exploration. Ahad is a member of the British Astronomical Association and his spare time interests include astrometric measurements of visual binary stars and proper motions of nearby stars, observation of deep sky objects and study of variable stars.
In 2004, he was the first person in scientific history to define an analytical approximation of the cosmic night sky's total integrated brightness ("Ahad's constant" of circa 1/300th of a Full Moon equivalent). He is the author of two novels in the popular First Ark to Alpha Centauri series.
[edit] Ahad’s constant
Ahad’s constant is an analytical quantification of the universe’s total background light flux reaching the Earth’s surface from all cosmic sources, such as stars, star clusters, galaxies, and quasars, excluding all light coming from the nearby Sun. It was first defined by Abdul Ahad in March 2004, as the end result of a logarithmic series whose input parameters are the apparent visual magnitude of every single cosmic source ever catalogued. The series is thought to converge toward a final value of some -6.5 magnitudes or approximately 1/300th of a Full moon's worth of light. The progression of the series is such that as one moves toward integrating light from fainter stars of lower magnitudes, the star count increases exponentially, but the cumulative contribution of light toward the constant itself tails off more rapidly, thereby resulting in convergence. The flux equations that lead to Ahad’s constant are defined as follows. Suppose we have two stars of apparent magnitude m1 and m2. Then their luminosities L1 and L2 are related by the Pogson Ratio:-
L2/L1 = 10^[0.4*(m1-m2)]
The luminosity of the pair of stars is L1 + L2 = L1(1 + L2/L1), and their combined magnitude is then given by:-
Mc = m1 - 2.5*log10 (1 + L2/L1)
For the general case, where the magnitudes of n stars need to be aggregated, we can generalize this by computing all the ratios:-
Li/L1 = 10^[0.4*(m1-mi)]
for all stars i from 2 through n. Then:-
Ahad’s constant = m1 - 2.5*log10 (1 + L2/L1 + L3/L1 + ... + Ln/L1)
The apparent visual magnitude m of a star whose absolute magnitude is M, as seen from a distance of d light-years is given by:-
m = M - [5 - 5 * log10(d / 3.2616)] Using the above formula the fall off in apparent magnitude of the Sun with increasing distance can be charted, thus:-
At a distance of circa 11,500 Astronomical units going radially outward from the Solar System the Sun's apparent light output matches Ahad’s constant. It is thus possible to draw an imaginary sphere around the Sun of such a radius, within which the Sun would remain the most supreme source of light, relative to the universe’s total background illumination:
The outer edge of such a sphere, in principle, defines an edge of the Sun’s monopoly of light and heat provision to the Solar System and nearby interstellar space; an effective end of its light dominion.
