The Arabic word “Ishraaq” is the name given to the time of day when the sun has totally ascended (risen) in the mornings. The “ishraaq” prayers are a two-rakah supererogatory prayer offered after the sun has totally risen.
It is the Sunnah of the Messenger of Allah ﷺ that he would lead the professors in the compulsory fajr prayer in the Masjid, then sit and commend and recall Allah Subhanah till the sun had totally risen; and afterward he would offer a two-rakah prayer and leave the Masjid (Mosque). This two-rakah prayer in the early morning after the sun has totally risen is known as the Israaq prayer.
The ‘chaasht’ prayer also known as the ‘Salat-ud-Duha’ and the ‘Salat-al-Awwabeen’ and its time begins a couple of hours after the sun has completely risen and lasts till the sun has reached its abject meridian at noon.
The salat-ud-Duha is a supererogatory prayer and is offered in two rakah combinations, and the maximum number of rakahs which the Prophet ﷺ prayed at this time was eight and according to another narration, twelve. Some of the eminent jurists and scholars in Islam said that one may pray as many rakahs of Salat-ud-Duha as one wishes or is convenient or easy for them.
Sayyiduna Anas ibn Malik RadiAllahu Anhu narrates that the Hazrat Mohammed Mustafa ﷺ said: Whosoever offers his morning (fajr) prayer in congregation, then remains seated making the dhikr of Allah until the sun rises, and thereafter offers two rakats, they will receive the reward of performing a Hajj and Umrah. (Sunan Tirmidhi Hadis no: 586)