Comment on ?asymmetry and variations of solar limb darkening along the diameter defined by diurnal motion in April 1981? by Neckel and Labs (1987)

Abstract

In a recent paper (Neckel and Labs, 1987a) a strong claim is made for detection of surprisingly large variations in photospheric limb darkening over time-scales of minutes to hours. Some of this evidence relies on re-interpretation of our measurements carried out at Kitt Peak between 1980–1982 (Petro et al., 1984). The purpose of this Comment is to draw attention to information we have published which suggests that the variations noted by Neckel and Labs are more likely to be of instrumental than solar origin.