[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: ITL - Prayer Time



Umer Farooq writes:
 > Salam Alikum,
 > 
 >    I'm trying to get prayertime api (CVS Snapshot 05/02/2004 on Suse9.1) 
 > working but the hours are not comming out right.
 > 
 >    ./ipraytime --latitude 42.02870000 --longitude -93.63880000 --utcdiff 
 > -6  --dst 1 --end --file ./def
 > 
 >    Also when I define the lat and long in a file it ends up giving me 
 > wierd numbers, and for some reason It won't take the method flag from 
 > the prompt.
 > 
 > Setting in my defination file:
 > 
 > City: Ames, IA
 > AngleMethod: 4
 > SeaLevel: 317 #(1003 Feet)
 > 

This is a problem with ipraytime not setting the right arguments. This
is now fixed on CVS.


 > For the hours it gives me the right time for Zhur when I compare it to 
 > http://www.islamicfinder.org/
 > but when I compare the time to http://soundvision.com/ it is off by 4 
 > minutes.. but soundvision and islamicfinder.org are both off from each 
 > other.. but both of them have the right sunrise time.. which I compared 
 > to USGS sunrise times and www.wunderground.com sunrise times. ??
 > 
 > 
 > Also I looked at this site http://www.ummah.net/astronomy/saltime/ in it 
 > the first formula adds (eot/60) while in the prayer time getThur() 
 > method you are subtracting.

I have some works by authors mentioned on the reference list on that
page (Qasimi .Y and Muneer .T ...etc) and they do mention that we need
to add the eot, however, the ITL's timeEquation uses negative values
for dial slow times instead of positive and there is no standard sign
for this that I'm aware of (negative is more common?).

 > 
 > For the EOT I get the method as it is described at 
 > http://en.wikipedia.org/wiki/Equation_of_time  but for finding out sun's 
 > declination I can't exactly get my head around it, can someone please 
 > explain.
 > 

There are many variants (mostly approximations) of the EOT and DEC
equations. Some accurate enough for this task others are not. I have
implemented many clear and verbose DEC formulas but they have proven
to be less accurate than this one. My reference while doing
comparisons is http://ssd.jpl.nasa.gov/cgi-bin/eph . I will be a
doing a more thorough review to the EOT and DEC equations later if
necessary.


 > Also I read that division by 15 should not be used if you are going to 
 > transfer deg to hour.. instead you should use 15.04107. Can someone 
 > please confirm.
 > http://www.stjarnhimlen.se/comp/riset.html
 > 

This is only necessary for calculation of Sunrise and Sunset for higher
latitudes (66+). The current ITL only supports such latitudes through
the "All Salats" extreme methods. This will be fixed soon.

 > 
 > Just a sugestion, I think it might be better to write RAD_TO_DEG in a 
 > standard format. A * (180/PI); instead of A / (PI/180.0); Also it be 
 > great if you can pass in the seaLevel from prompt.
 > 

You can now set "--sea-level" or "-sea" for short. 


Regards,
Thamer Mahmoud



 > -- 
 > Umer Farooq
 > Octadyne Systems
 > umer at octadyne dot com
 > +1 (519) 635-2795 voice
 > +1 (208) 275-3824 fax
 > 
 > 
 > LOOKING FOR A USED CAR IN IOWA VISIT: http://www.IowaMotors.com
 > 
 > 
 > WARNING: ------------------------------- The information contained in 
 > this document and attachments is confidential and intended only for the 
 > person(s) named above. If you are not the  intended recipient you are 
 > hereby notified that any disclosure, copying, distribution, or any other 
 > use of the information is strictly prohibited.  If you have received 
 > this document by mistake, please notify the sender immediately and 
 > destroy this document and attachments without making any copy of any kind.
 > _______________________________________________
 > Developer mailing list
 > Developer at arabeyes dot org
 > http://lists.arabeyes.org/mailman/listinfo/developer