What is the correct time for Duha prayer: Should one wait until the sun is a spear high, or rely on the scholars' estimation of 15-20 minutes after sunrise, or wait half an hour, or is what the questioner currently does, praying 20 minutes after sunrise, correct even if the sun has not appeared?

The time for the Duha prayer begins when the sun has risen to the height of a spear, by scholarly consensus. Some scholars estimate the beginning of the permissibility of performing supererogatory prayers to be fifteen minutes after sunrise. If the questioner relies on an approved calendar, then waits the recorded time and delays beyond it by fifteen minutes or more, what she does is correct, and she is not required to delay for half an hour. It is not a condition that she sees the sun, as long as the calendar is approved. "Sunrise" refers to the sun's appearance, but supererogatory prayers are not permissible until it has risen to the height of a spear. If she prays before the sun rises and elevates, while it is possible to see it, then that is not legislated and means that the calendar is incorrect.