It is obligatory to perform prayer.

It has been made obligatory for the Ummah of Muhammad, just as it was made obligatory for the ummahs of the past. Prayer times are calculated according to the sun. When the sun is directly overhead and inclined towards the west, the time for the Noon Prayer begins. When everything's shadow is as big as itself, it is time for the Afternoon Prayer. When the sun sets, the time for Maghrib Prayer begins. When the light in the sky disappears and the sky becomes completely dark, the time for the Isha Prayer begins. When the first and second dawns appear, that is, when a redness begins to appear in the air, the time for the Morning Prayer begins and ends when the sun rises.

Every prayer can be performed until the next time. The time for the Morning Prayer is until sunrise.

You can find the details of the above explanation and even much more in our Fazilet Calendar...