# CAOSP abstracts, Volume: 28, No.: 3, year: 1999

*Author(s):* DANYLEVSKY, V. O.
*Journal:* Contributions of the Astronomical Observatory Skalnate Pleso,
vol. 28, no. 3, p. 201-209.
*Date:* 03/1999
*Title:* The solar diameter determination from data of the 1991 July 11 solar
eclipse photoelectric observation
*Keyword(s):* SOLAR DIAMETER, ECLIPSES: PHOTOELECTRIC OBSERVATIONS
*Pages:* 201 -- 209

**Abstract:**
It is known that the solar diameter value obtained from the solar eclipse
observations depends much less on atmospherical effects than those determined
from the ground-based solar diameter measurements. The solar semidiameter,
totality duration and some other parameters of the 1991 July 11 solar eclipse
have been determined using photoelectric observations at 4 sites near the
northern edge of the path of the total eclipse. The observational data have
been obtained at the spectral band covering the wide region from 0.40 to 1.0
micrometer, and effective wave-length is equal to approximately 0.65
micrometer. To determine the solar semidiameter, a theoretical light curve was
described by integral equation and fitted with a least squares method to each
observational light curve. The solar semidiameter was one of the best-fit
parameters. The lunar limb corrections have been obtained from Watt's charts,
the Sun's and Moon's apparent ephemerides have been computed using LE200/DE200
fundamental ephemerides. As the solar semidiameter is a nonlinear parameter of
the theoretical light curves, the nonlinear programming has been used to
minimize the functional in the least squares method. The average value of the
solar semidiameter obtained from 4 estimations is equal to 959.69 +/- 0.12
arcsec for Sun-Earth distance 1 AU. Due to he fact that the influence of the
chromosphere light on the eclipse light curve was taken into an account
partially and the linear assumption on the solar limb darkening used, the
result obtained is only preliminary one. However, the results obtained show
that our observation data do not contain any significant errors. The result
can be corrected in future.

Full text version of this article in
PostScript
(600dpi) format compressed by gzip; or in
PDF.