Monday, February 25, 2019

Why is dawn in Indonesia too early? (5)


For long, some astronomers have a presumption that the light pollution (in addition to air pollution) might delay the presence of dawn. In this fifth video, based on the real astronomical data, we proved that the presumption is groundless. 

ISRN-UHAMKA used an SQM to collect the sky-brightness data in two different places in Yogyakarta on May 5 and 6, 2018. The data collection took place in two different places, Krakal Beach and Panguk Hill when the moon phase was a waning gibbous moon, only 4-5 days after the full moon. 

The estimated dips from the SQM data on these two days were -16.7 degrees and -15.1 degrees, in spite of the fact that the sky was highly light polluted. The illuminated parts of the moon were 78% and 70% respectively. The above-mentioned dips are much deeper than the average dip of -13.3 degrees estimated from 206 days of the SQM data.



To verify the results, we used a high-resolution DSLR camera Nikon D5100 capable of producing an image with more than 16 million pixels. Some image processing techniques confirm the presence of the SQM's dawns. Therefore, the present Fajr call is really too early. Please, check the enclosed 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)
4) Why is dawn in Indonesia too early? (4)

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