Analysis of the detectable stellar magnitude limit using CCD camera in daytime sky background

The method to estimate the detectable stellar magnitude limit in daytime sky background is introduced. Based on the results of the contrast of star to sky background in daytime, the detectable stellar magnitude limits are computed and analyzed as functions of observing heights, solar zeniths angle, wavebands and stellar spectral types for 3°3° field of view. The results show that the detectable stellar magnitude limits linearly increase with observing height and solar zenith angle. A higher detectable stellar magnitude limit is obtained by using longer wavelength bands for stars of K and M types. For the case of 25 km observing altitude, the field of view of 3°3°, the maximum detectable stellar magnitude limit is 6.3 when the sun is out of 20° line of sight.