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  1. #1

    Default Help!!

    To the professionals out there.
    I have the target and sun parameters sorted - but am battling with the moon calculations.
    The algorithms are based on www.stjarnhimlen.se/comp/ppcomp.html and www.stjarnhimlen.se/comp/tutorial.html.
    The calculation results correspond with the tutorial and even with Skytools 3, but not with other tools and almanacs.
    For instance for my location 33 59 20 S and 25 31 49 E for today I get
    Rise: 19:01 Transit: 01:12 Set: 07:25
    Skytools:
    Rise: 19:10 Transit: 01:16 Set: 07:27
    TheSkyX and others
    Rise: 19:07 Transit: 00:34 Set: 06:37

    So obviously Skytools and I have got it wrong.
    So, can anyone help me with the correct algorithm (to calculate the moon's alt/az for a particular time and location.)
    Would be much appreciated.

    dalelieb@iafrica.com
    Dale

  2. #2
    Join Date
    Oct 2005
    Location
    Mesa, AZ
    Posts
    33,159

    Default

    Ha! I did a special ACP add-on for a customer that includes Stephen Moshier's aa.exe, a useful command line tool for moon, sun, etc. Attached is a set of items that might help. You could execute aa.exe as a shell program and capture standard out. With my added -moon option it simply puts out the RA/Dec of the moon.

    Code:
    This is Stephan Moshier's 'aa' planetary ephemeris program, modified by Bob Denny <rdenny@dc3.com>. It is intended to be used by ACP to get the current topocentric coordinates of the Moon for use within an ACP observing plan. In its normal mode, invoking as aa.exe, it will ask questions and produce ephemerides for the major planets, the moon, and the sun. However if invoked with a command line of 'aa -moon' it will simply write the topocentric coordinates of the moon in decimal format (hours, degrees) at the current instant to its standard out. 
    
    The program requires a config file called aa.ini that resides in (preferably) Common\Public Documents, or in the same directory as aa.exe. It must look like this:
    
    
    --- snip ---
    -71.13     ; Terrestrial longitude of observer, degrees negative west
    42.27      ; Geodetic latitude, degrees
    0.0        ; Height above sea level, meters
    12.0       ; Atmospheric temperature, deg C
    1010.0     ; Atmospheric pressure, millibars
    1          ; 0 - TDT=UT, 1 - input=TDT, 2 - input=UT
    0.0        ;Use this deltaT (sec) if nonzero, else compute it.
    ------------
    
    
    The sources for this program are available on request from Robert B. Denny, DC-3 Dreams, SP at no charge (as is the program itself). Contact me at rdenny@dc3.com. 
    
    
    Bob Denny  09-May-2014
    -- Bob

  3. #3

    Default

    Thanks Bob - I will give it a bash this evening.

    Dale

  4. #4

    Default

    Bob,
    I think I misunderstood - can't find aa.exe
    Can you mail it?

    Dale

  5. #5
    Join Date
    Oct 2005
    Location
    Mesa, AZ
    Posts
    33,159

    Default

    Oh, it would have been nice to have included the zipfile!!
    Attached Files Attached Files
    -- Bob

 

 

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