Improvements in the use of daytime star observations from a transit circle

The Seven-inch transit circle of the US Naval Observatory presently located in New Zealand is able to observe stars in the daytime to visual magnitude 5.3 using an image dissector. Thus a far greater range of day stars have been observed than is possible with a visual instrument. The daytime observations have shown changes of 0.70 s of arc for the declination clamp difference and 0.01 s of time for the clock corrections from the values determined using the night observations. The use of the daytime determined adjustments allows for a more homogeneous daytime system. With the increased number and wider distribution of daytime observations, the traditional method of adjusting the daytime system of observations to the nighttime system, necessary in the formation of an absolute star catalog, can be improved