In your article on hefsek taharah, you write: "Busy women who have a tendency to forget, especially on short winter afternoons, and who don't find these exams painful or troublesome should do one in the morning and repeat it in the afternoon. In this way they have a "backup" in case of forgetting."

How early can the backup bedika be done? In certain parts of the globe (like the UK) the sun rises in the Winter very late. In Manchester today alot hashachar was at 6:25 and sunrise at 8:20.

This can cause a huge problem. For example a woman that leaves her home at 6:15 for work or gets involved in getting her children to school and does the bedika too early may have a problem, especially if she is unable to get in a bedika before shkiya which is very early. Is the morning bedika valid if it was done before alot hashachar?

Keep up this invaluable service.