Time verification of twilight begin and end at Matrouh of Egypt

Hassan, A.H.; Hassanin, N.Y.; Abdel-Hadi, Yasser A.; Issa, Islam

doi:10.1016/j.nrjag.2013.06.008

Cited by 9 publications

(4 citation statements)

References 3 publications

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“…In addition to the naked eye observations which recorded on four locations in Egypt; Matrouh, Bahria, Kottamia and Aswan and all had the same results. In 2014, Hassan et al (2014aHassan et al ( , 2014b concluded that there is a good agreement between the photoelectric measurements and the naked eye observations of the beginning of morning twilight (true dawn) in four locations in Egypt (Issa and Hassan, 2008a, 2008b, 2008cIssa et al, 2009Issa et al, , 2011Hassan et al, 2013Hassan et al, , 2014aHassan et al, , 2014bHassan and Abdel Hadi, 2015). All the above mentioned results are summarized in Table 5.…”

Section: Comparison Between the Current Results And The Preceding Resmentioning

confidence: 88%

Twilight observation by the naked eye of the dawn sincere at Hail and other areas in Saudi Arabia

Khalifa

Hassan

Taha

2018

NRIAG Journal of Astronomy and Geophysics

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Naked eye observations of morning twilight phenomenon at Hail and other areas of Saudi Arabia are recorded. During the interval from 2014 to 2015, about 80 morning twilight observations were carried out in Hail at longitude λ = 41°42′E and latitude φ = 27°31′N for a desert background. The phenomena was followed over azimuth angles ranged from 0°to 20°of solar vertical direction and from 0°to 10°along the altitudinal range. By selecting 32 days with a very good visibility, it was found that Sun depression, D o , lies in a range between 13.48°a nd 14.69°with an average of 14.014°± 0.317. The difference between our obtained value and that one which is currently applicable in Saudi Arabia is about 4°. The results indicate that dawn (white thread browser) occurs at a sun vertical depression angle D o = 14.66°(mean + 2SD) according to the normal eye estimations. The results at different areas in the deep desert in KSA showed that the beginning of morning twilight and true dawn is at sun vertical depression D o = 14.88°(mean + 1SD). The current study shows significant results, which are comparable with both naked eye observations and photoelectric measurements of true dawn in both Egypt and Libya for desert background.

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Section: Comparison Between the Current Results And The Preceding Resmentioning

confidence: 88%

Twilight observation by the naked eye of the dawn sincere at Hail and other areas in Saudi Arabia

Khalifa

Hassan

Taha

2018

NRIAG Journal of Astronomy and Geophysics

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“…The spread of the dawn of Sadiq is not like the light of a lamp that has just been turned on, where the light will be immediately visible. [30] The appearance of the dawn light of Sadiq is relatively subtle and slow so that the naked eye cannot judge when it starts, we only realize when it gets brighter [31].…”

Section: Ulema Opinion On the Use Of Information Technology In Assist...mentioning

confidence: 99%

The Urgency and Contribution of Information Technology in Verifying the Beginning of Shubuh Time and the Height of Hilal Determining the Beginning of the Hijri Month

2023

al-marshad.j.astronomi.n.a.dan.ilmu-ilmu.berkaitan

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Article InfoThe sun's altitude of -20° as a reference for determining the beginning of shubuh time used by the Ministry of Religious Affairs is questionable. Meanwhile, in terms of hilal height as one of the criteria for determining the beginning of the Hijri month, the Ministry of Religion has also undergone adjustments and changes in 2022. The new criteria of MABIMS mention criteria in the form of a hilal height of 3° and an elongation angle of 6.4°. This research answers two formulations of problems, first, the urgency of information technology in determining the criteria for the beginning of dawn and the criteria for determining the beginning of the Hijri month in Indonesia. Second, the extent of the contribution of information technology in determining the criteria for dawn and the criteria for determining the beginning of the Hijri month in Indonesia. Analytical descriptive methods with fiqh and scientific approaches are used to answer both formulations of the problem. The study produced two findings. First, according to Islamic law, the presence of digital-based information technology is considered legal to be used and utilized to provide certainty and trust in Islamic legal products. Secondly, technology has made a major contribution in verifying dawn criteria and establishing new criteria of MABIMS.

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“…The scattered sunlight, a result from of the sun being located below the horizon, will produce a proportional effect between sun altitude, and the light intensity and color spectrum of twilight sky (Yallop & Hohenkerk, 1996). The depressed sunlight reddens the sky at near sunset altitude, and decrease its brightness, that will reach its minimum and stable intensity at the range of 16-18° of solar depression (Hassan et al, 2013). This will signify the end of sunlight scattered radiation of twilight and the commencement of the night sky (Shariff et al, 2012).…”

Section: Introductionmentioning

confidence: 99%

“…Parameters of Twilight When Brightness Stability is ReachedThis behavior as shown by Table3is important as the degree of twilight brightness upon reaching its stability at suburban and urban site defy the major work found by the twilight study(Belokrylov et al, 2011;Hassan et al, 2013;Koomen et al, 1952;Shariff et al, 2012), which is around 16°-18°. This result shows a major impact of light pollution on the twilight brightness pro le that never been highlighted before.…”

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confidence: 96%

Alteration of Twilight Sky Brightness Profile by Light Pollution

Faid,

Nawawi,

Saadon

et al. 2023

Preprint

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The phenomenon of twilight been stipulated as naturally dependent on the variables of solar depression, aerosol concentration and ozone composition. The unique color spectrum of twilight is attributed by ozone layer and aerosol, whereas its brightness is heavily relying on the altitude of sun below horizon. While all the natural dependent is being researched extensively, the impact of light pollution on the brightness of the twilight is not being explored thoroughly. The objective of this study is to find out the alteration of light pollution towards the natural behaviour of twilight sky brightness. Total of 84 data of twilight brightness was collected from 2014 until 2022 using Sky Quality Meter, and the specific location with profile classified as urban, suburban and pristine is investigated to study the impact of light pollution on twilight brightness. The result demonstrates that the stability of twilight brightness, which naturally factored by solar depression within the range of 18°, discovered to be heavy influenced by the zenith light pollution of the location sky, as evidenced by location that has zenith pollution of 17.11, 19.77, and 21.39, has horizontal twilight brightness of 14.84, 19.55 and 21.2 and solar depression during brightness stability at 11.5°, 15.67° and 17.49°.

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Time verification of twilight begin and end at Matrouh of Egypt

Cited by 9 publications

References 3 publications

Twilight observation by the naked eye of the dawn sincere at Hail and other areas in Saudi Arabia

Twilight observation by the naked eye of the dawn sincere at Hail and other areas in Saudi Arabia

The Urgency and Contribution of Information Technology in Verifying the Beginning of Shubuh Time and the Height of Hilal Determining the Beginning of the Hijri Month

Alteration of Twilight Sky Brightness Profile by Light Pollution

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