This tool provides hourly airmasses, parallactic angle and heliocentric-barycentric corrections based onsite, date, and object coordinates information. Times are given forthe local time, including daylight saving times when applicable. Please be aware that the dates of the change of savingtimes are generally not correct, and there may be difference with local time around these dates.
Select site, object coordinates and date; then press Compute. The time step can also be chosen (defaults to 1 hour).
More detailed information is provided is a separate document Notes for Skycalc by John Thorstensen.