Tuesday, February 19, 2019

Why is dawn in Indonesia too early? (4)


ISRN has been using four sensors to detect the presence of dawn to mark the commencement of the Fajr prayer for Muslims in Indonesia. The main instrument is a Sky Quality Meter (SQM) which records the sky-brightness data. In the first video, we demonstrated the use of 198 data for the Fajr and 149 data for the Isha to conclude that the dawn actually occurs when the sun is at the dip of -13.3 degrees, not at -20 degrees like what we have been practicing for tens of years. This simply implies that our Fajr call is actually about 26 minutes too early. On the contrary, the Isha call is about 26 minutes too late. The latter might not be as crucial as the former one. However, it is becoming dangerous for those who perform their Maghreb prayer too late because the timings might have belonged to the Isha time.

In our second video, we showed a verification process using an All Sky Camera (ASC) to detect the presence of the real dawn, whilst in the third video, a verification process by an independent third party is explained.


In this fourth video, we used a low-cost gadget camera to verify the presence of the real dawn. All these verification processes further confirm that the SQM detected dawn is compliant with the actual physical data. Please check the above video.

Previous video:

1) Why is dawn in Indonesia too early? (1)
2) Why is dawn in Indonesia too early? (2)
3) Why is dawn in Indonesia too early? (3)

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