06-06-2021, 04:58 PM

On the Argus Array page the figure given for the light gathering capability of the Argus Array, just over 10^27 m^2, is inconsistent with the description of the array as 8000 20 AU diameter spheres. Assuming the array is composed of 8000 20 AU wide bubbles its cross section would be pi*(10 AU)^2*8000 or 5.625*10^28 m^2. This discrepancy seems to be caused by two factors. First what seems to be the original source for the 10^27 figure uses a factor of 2pi for the cross-sectional area calculation instead of just pi, while the surface area that could view an arbitrary portion of the sky would be 2pi*r^2 (as the surface area of one hemisphere would be half of the sphere's total surface area of 4pi*r^2) much of this surface is at an angle and the total cross section and thus effective light gathering area would be still pi*r^2. The other cause seems to be an order of magnitude error. While 2pi*(10 AU)^2*8000 is still not consistent with 10^27 m^2 if 10 AU is substituted with 1 AU then the resulting figure is 1.125*10^27 m^2 or just over 10^27 m^2 which matches what currently appears in the article.

In order for the Argus Array page to be self-consistent either the light gathering area must be increased to 5.625*10^28 m^2 (and the necessary photon collection times be recalculated), the number of sensor elements be reduced 160 20 AU telescopes, the number of elements be kept the same but the diameter of each telescope be reduced from 20 AU to 2√2 AU, or some combination of the previous.

In order for the Argus Array page to be self-consistent either the light gathering area must be increased to 5.625*10^28 m^2 (and the necessary photon collection times be recalculated), the number of sensor elements be reduced 160 20 AU telescopes, the number of elements be kept the same but the diameter of each telescope be reduced from 20 AU to 2√2 AU, or some combination of the previous.