Program listing for RPN Sunrise/Sunset

[Dieter]

(10-14-2017 09:20 PM)Craig Bladow Wrote:  Still get a DATA ERROR, so need to do some more debugging.

FTR: I tried the HP41 version in V41 and it works just fine. The times for today exactly match those from a good online calculator.

However, I think the program can be improved. I also wonder if the FLOOR routine is really required. But I don't get any errors. At least not for my location and timezone. What values did you try?

Edit: The program calculates floor(R10/90) and floor(R11/90). Both R10 and R11 are the result of a mod 360 operation which always returns a value >= 0. So I think the complete FLOOR routine is obsolete and can be replaced with a simple INT command. And maybe the whole thing can be done even more elegantly with MOD.

Edit 2: I now have replaced the following lines of the original program...

Code:

 99    ATAN
100    360
101    MOD
102    STO  11
103    RCL  10
104    90
105    /
106    XEQ 'FLOOR    Floor function.  External program
107    90
108    x
109    +
110    RCL  11
111    90 
112    / 
113    XEQ 'FLOOR    Floor function.  External program
114    90
115    x 
116    -     
117    15
118    /     
119    STO  11

...with this:

Code:

 99    ATAN
100    90
101    MOD
102    RCL  10
103    90
104    /     
105    INT
106    90
107    x 
108    +
109    15
110    /
111    STO  11

And it seems to work. But please do your own tests and report here if you find any cases where errors occur.

Dieter