Re: [Bug-gcal] gcal (gnucalendar): BUG: MOONRISE/SET CALCULATIONS: TIMEZONE -1:00 AT LEAST.

[Giuseppe Scrivano]

Thanks for your report, I have just committed a patch for it.

The problem affects only the timezone=-1 as this value interferes with
an error return code.

Cheers,
Giuseppe



John McGowan <address@hidden> writes:

> There are some bugs in the astronomical calculations. I happened to run
> across these (moonrise, moonset but did not check sunrise, sunset or other
> calculations) which affect (at least) TimeZone=-01:xx (just off the west
> coast of England? I don't live there.)
>
> I finally managed to see what moonrise, sunrise, etc. gcal reports as for
> moonrise, sunrise, etc. - namely the one occurring during the local day as
> specified by the use of the local adjustments in the astronomical special
> text sections (NOT the time-offset), such as:
>    %(+{latitude_longitude},{adjustment}
> where the [adjustment] is (+|-)[hh:mm|mmm].
>
> For some reason, in trying to check what gcal really does I was calculating
> moon rise in NYC (of course the moon rises more than once during the course
> of the year) and seeing which of those moon rises was reported as an event
> occurring on 10th May 2010 in various time zones. There is a problem with
> at least one time zone.
>
> MOON RISE:
>
> COMMAND:
>    gcal -f/dev/null -# "0 B %(+403600-0741012,[local_adjustment]" %20100510
> (May tenth 2010 - find the universal times for moonrises in NYC and see which
> of those universal times are reported as occuring for different time zones,
> i.e. which moonrise time it chooses to report if it was reporting a moonrise)
>
>                                                                  RESULTS
>   gcal -f/dev/null -# "0 B %(+403600-0741012,-3:00" %20100510     4:33
>   gcal -f/dev/null -# "0 B %(+403600-0741012,-2:00" %20100510     5:33
>   gcal -f/dev/null -# "0 B %(+403600-0741012,-1:00" %20100510     7:33
>   gcal -f/dev/null -# "0 B %(+403600-0741012,0:00" %20100510      7:33
>   gcal -f/dev/null -# "0 B %(+403600-0741012,1:00" %20100510      8:33
>   gcal -f/dev/null -# "0 B %(+403600-0741012,2:00" %20100510      9:33
>
>   gcal -f/dev/null -# "0 B %(+403600-0741012,-1:30" %20100510     7:03
>   gcal -f/dev/null -# "0 B %(+403600-0741012,-0:30" %20100510     7:03
>
> As these use the local ajustment to report the local time, the UT of the 
> moonrise
> selected is obtained by sutracting the local adjustment from the reported 
> local
> times giving:
>
>     TZ     Calculated moonrise UT
>   -3:00    7:33
>   -2:00    7:33
>   -1:30    8:33
>   -1:00    8:33
>   -0:30    7:33
>    1:00    7:33
>    2:00    7:33
>
> (all these timezones calculate *this* moonrise which occurs during their local
> day while other timezone results show that the moonrise for which the 
> calculation's
> result is presented is the moonrise which occurs during that timezone's local 
> day,
> such as the one after this, the next day at 07:58 UT which is used in TZ=-8)
>
> and it appears that the moonrise using TZ=-1:xx is calculated as occuring
> at 8:33 UT while using the other time zones shows it occurring at 7:33 UT.
>
>
> The same occurs for:
>
> MOON SET:
>
> COMMAND:
>    gcal -f/dev/null -# "0 B %)+403600-0741012,[local_adjustment]" %20100510
>
>   gcal -f/dev/null -# "0 B %)+403600-0741012,-3:00" %20100510     17:51
>   gcal -f/dev/null -# "0 B %)+403600-0741012,-2:00" %20100510     18:51
>   gcal -f/dev/null -# "0 B %)+403600-0741012,-1:00" %20100510     20:51
>   gcal -f/dev/null -# "0 B %)+403600-0741012,0:00" %20100510      20:51
>   gcal -f/dev/null -# "0 B %)+403600-0741012,1:00" %20100510      21:51
>   gcal -f/dev/null -# "0 B %)+403600-0741012,2:00" %20100510      22:51
>
>   gcal -f/dev/null -# "0 B %)+403600-0741012,-1:30" %20100510     20:21
>   gcal -f/dev/null -# "0 B %)+403600-0741012,-0:30" %20100510     20:21
>
> As these use the local ajustment to report the local time, the UT of the 
> moonrise
> selected is obtained by sutracting the local adjustment from the reported 
> local
> times giving (as the calculated moonset in NYC reported as occuring during the
> local day, 10th May 2010 in various timezones):
> :
>
>     TZ     Calculated moonrise UT (time reported minus TZ)
>   -3:00    20:51
>   -2:00    20:51
>   -1:30    21:51
>   -1:00    21:51
>   -0:30    20:51
>    1:00    20:51
>    2:00    20:51
>
> and it appears that the moonrise using TZ=-1:xx is calculated as occuring
> at 8:33 UT while using the other time zones shows it occurring at 7:33.