What is the ruling on looking up to the sky while supplicating after the obligatory prayer?

Supplicating after the obligatory prayer while habitually raising the hands or doing so collectively is an innovation (bid'ah). However, supplicating without these habits is permissible. Raising one's gaze to the sky during prayer is forbidden because it contradicts humility (khushu'), but it is permissible outside of prayer, whether during supplication or at other times.