al-Hidaya min al-dalala fi ma'rifat al-waqt wal-qibla (al-Qalyubi)

Al-Hidaya min al-dalala fi ma'rifat al-waqt wal-qibla wa-ma yata'allaq bihima min ghayr ala, also known as Muqaddima fi ilm al-waqt wal-qibla (al-Azhar Library no. 6/1942), is by Shihab al-Din Abu al-Abbas Ahmad ibn Ahmad ibn Salama al-Qalyubi (d. late Shawwal 1069/1658), whom the book describes as combining the religious and rational sciences, skilled in medicine, and in the habit of repeating explanations for his students. ¹

• It deals with determining times such as prayer times, the Hijri and Coptic years, and finding leap and common years, with linguistic and juristic definitions of time, month and year. ^{1 2}
• In his introduction he says he included what is easy to learn and depends on no particular instrument, time or place. ²
• He ends with the observation that he examined most mihrabs in the cemeteries of Egypt and found them misaligned, so that in his view they may not be relied on; the book says modern research has confirmed this for some mihrabs. ²
• It has an introduction, twelve chapters and a conclusion, copied by Abu al-Su'ud al-Rifa'i al-Shafi'i in 1078 AH. ²