On the radius, angular at 1 AU or linear, of the Sun

Links collected in June 2000 by Jenik Hollan seem to show, that the standard mean solar angular radius is somewhat less than 969.0", but which value would be the best, is difficult to say. A value following from the table available at obspm, 959.63(10)", may be the best one. How its standard uncertainty have been obtained, I do not know.

The following links are interspersed by quotations from them (resulting angular radii in parentheses have been added by me).

J.H.

  1. Shrinking Sun Debate and Poll: A recent measurement of the solar diameter is that of Brown & Christensen-Dalsgaard (1998). From data taken over the period 1981-1988, they report a radius of 695,508 +- 26 km, with no evidence... (angular diam. at 1 AU follows as 958.96(4)". I have not been able to find the original publication.)
  2. Is The Sun Shrinking? Part Two:
  3. many references up to 1983, just changes are mentioned in the text.
  4. A. D. Wittmann: The solar diameter derived from Tobias Mayer's: 2. The observations split into two distinctly different groups (with a gap in between). The first group (N=120, 1756-1758) is much more homogeneous and considerably more accurate than the second group (N=13, 1760-1761), and it may, therefore, be justified to completely disregard the second group:

    1st group: R = (960.46 +- 0.11)" [N=120] 2nd group: R = (959.85 +- 0.72)" [N=13]

    Both: R = (960.40 +- 0.12)" [N=133]

    3. If, with due allowance for the accuracies involved, this is compared to recent drift timing results obtained during a joint project by A.D. Wittmann at Tenerife in 1981/1990-1997 (1st group) and by M. Bianda at Locarno in 1990-1997 (2nd group), viz.

    1st group: R = (960.59 +- 0.03)" [N=7627] 2nd group: R = (960.59 +- 0.05)" [N=2244]

    Both: R = (960.59 +- 0.02)" [N=9871]

  5. Useful Constants: Solar radius R_sun = 6.9599(7)*10^10 cm (implied 1 AU angular radius is 959.63(10)")
  6. Some astronomical constants Solar radius (Rs) 6.953 E 8 [m]
  7. Sun Fact Sheet: Apparent diameter from Earth At 1 A.U.(seconds of arc) 1919.
  8. diametre solaire: La valeur moyenne du demi-diametre observé est de 959".42 +/- 0".01 pour les mesures visuelles et de 959".40 +/- 0"01 pour les mesures CCD.
  9. (the above Calern data themselves)
  10. Cholett, Sinceac on Calern results: attenuation and conducts to the mean value 959.44"+-0.02". Taking account of all the informations given by the CCD observations, correlations between the Fried parameter r0 and the derivative width, and between r0 and the solar radius R, are found, in the results obtained by purely numerical methods. These results give us the possibility to evaluate, for r0->{infinity}, the corresponding values of the derivative width and the solar radius outside the terrestrial atmosphere. In these conditions, the mean solar radius is found to be equal to 959.63"+-0.08". The second series (column model on Table) obtained by the use of the presented model, conducts directly to a corrected mean result R=959.64"+-0.02". One can see that the corrected
  11. http://seal.nascom.nasa.gov/~bfleck/IAU203/Abstracts/andrei.pdf: Brazil data 1997 to 2000, mean 959.16(1)" for 563.5 nm eff. wavelength and 168 nm bandpass.