Re: ITL library & kprayertime

[abdulhaq <al-arabeyes at alinsyria dot fsnet dot co dot uk>]

salaam Thamer

Thanks for the prompt reply. I don't *know* of any tool which is more accurate 
than ITL, in that I have no idea of which times for maghrib are in reality 
correct. It's also very difficult to actually observe the correct time as I 
live in a city and also as you know the shape of the Earth at the point you 
are measuring also obviously affects times.

One other possible discrepancy as well as the very valid ones that you 
mention, is to make sure that the disc of the sun has entirely dropped below 
the horizon. Does the ITL library ensure this? Athough this only takes under 
a minute around here (central England).

Do you know what authority has said that the algorithm you are using is 
accurate? The reason I am concerned is that, obviously, praying 3 or 4 
minutes late is no problem, but praying even one minute early invalidates the 
prayer, as you well know.

Is there a web site or other data source that you know of for instance that 
provides actual maghrib times at various locations and dates, allowing me to 
make extra sure?

I'm sorry to raise all this again but I just want to be sure before making 
everything available for public download.

BTW, my lat is 52.6432, my long is -1.10333. Your program gives for today 
(29-4-04), 20:25. The Kamal Abdali algorithm gives 20:28. Yesterday there was 
a four minute discrepancy.



jazaakallahu khairan
wassalaam

On Thursday 29 April 2004 08:34, Thamer Mahmoud wrote:

> There are many factors that might produce diffenreces between the
> tools that you have tested and the ITL. Since the ITL library (and
> maybe the other tools as well, I'm not sure) uses a very common
> Sunrise and Sunset formula, I suppose that these differences in
> results are due for some other "side factors". Such as:
>
> * leap or non-leap year awareness.
> * differences in the default astronomical/math values used.
> * Excessive or bad rounding.
> * lat/long transformations (deg to rad...dms to dec ...etc.)
>
> Please provide the names of these tools and a specific location values
> where you know, for fact, that these tools provide more accurate
> Maghrib prayer times than the ITL. Inshallah, I will look into this,
> and I will also have another look at handling the "side factors" in
> the ITL as well.
>
> On whether it is OK to be released to the public, I'm biased ;), but
> in my experience the library does produce accurate results, so the answer
> is yes.
>
> If you have any more questions, bug reports, or feature suggestions,
> let us know.
>
> Regards,
> Thamer Mahmoud
>
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