Source:Āloka-saññā
'perception of light'.
The recurring canonical passage reads:
"Here the monk contemplates the perception of light. He fixes his-mind to the perception of the day; as at day-time so at night, and as at night, so in the day. In this way, with a mind clear and unclouded, he develops a stage of mind that is full of brightness."
It is one of the methods of overcoming drowsiness, recommended by the Buddha to Mahā-Moggallāna (A.VII. 58). According to D. 33, it is conducive to the development of 'knowledge and vision' (s. visuddhi), and it is said to be helpful to the attainment of the 'divine eye' (s. abhiññā).
Might this be referring to Kasina Meditation? I saw some threads on Stackexchange about this but the answers merely referred to the commentary and i dont think it is sufficiently instructive.Source:Buddhagosa's Commentary based on Early Commentary
...lead to the casting out of sloth and torpor: ... reflection on the perception of light;...
in him who reflects on the brightness or the light of the moon, a lamp or a torch by night, and on the light or brightness of the sun by day...
The meaning should be understood thus: Sloth and torpor vanish in him, too, who at night is reflecting on the image of the perception of the brightness of the sun he got by day.
