HAF 9. januar 2005 - IV
- Problemer i den muslimske kalender:
1. Det muslimske år har 354 eller 355 dage. Det betyder at helligdagene hvert år rykker 10-11 dage frem i forhold til den Gregorianske kalender, som følges i Danmark og det meste af verden. Pga. at den islamiske kalender har disse indbyggede problemer, følger de fleste muslimske lande begge kalendere.
2. "For a long time, many Muslims in many parts of the world have experienced considerable confusion and bitterness about the dates of our Islamic festivals, which should really be occasions for happiness and getting together ".
Fra www.assidq.org/darusalam/Which%20Hilaal.htm
- Første syn er blevet en "videnskab", se www.isfahan.ir/kamaneasemani/lec/yallop.html
- og
Thus as a "guide" to reduce errors, we should use Astronomical Calculations for Naked Eye Hilaal Sighting Criterion e.g. Dr. Durrani’s results or Br. Shaukat’s or Yallop’s criterion in MoonCalc. As mentioned before, however, it is important to use the correct calculations – not calculations for the astronomical dark new moon, or simply moonset after sunset, but calculations for naked eye visibility of the young crescent Hilaal. The time after astronomical new moon birth is NOT the best determining factor for hilaal visibility. Instead the angular separation between moon and sun at local sunset must be at least 7 or 8 degrees for Hilaal to be visible. (7 degrees is the theoretical minimum "Danjon limit" agreed by Astronomers). For different months this could lead to different minimum time between sunset and moonset for Hilaal to be visible by naked eye.
Men vi vil ikke lave videnskab ud det, men koncentrere os om den personlige oplevelse.
- Gode observationsbetingelser:
1) Månen nær perigæum - stor hastighed
2) Ekliptikal bredde skal være max eller min - giver stor afstand
3) Stor observationshøjde - lille ekstinktion
Absorbans
Se mere i S&T februar 2004 side 102-106.
Lad os se på nogle rekorder:
Naked eye rekord:
Stephen O´Meara: Mount Wilson, 900524, 15h32m/9,1°
Optical aided rekord:
Moshen Mirsaeed, Iran: 40x150 binoculars, 020907, 11h40m/7,5°
Hvad er din personlige rekord?
Godt tidspunkt:
Find første dato, hvor solnedgang er xx timer efter en nymåne!
Leiria - Portugal
The waning crescent Moon was just 20.6 hours from new when Luis Carreira of Leiria, Portugal, caught it last October 13th at 6:12 Universal Time. The Moon was only 3° above the horizon, and the Sun was 7° below the horizon. "l was extremely lucky," Carreira writes, "since in my area, dawns this clear and unfogged are quite rare." He used a 90-millimeter f/5.6 refractor as the lens on a Nikon D70 digital camera.
