Hi John ------------------------------------------------------------------ > > 2. on the 21. July 2010 at 00:15.00 the moon completely >disappeared below > > the south-western mountain-horizon. When I >simulate this time then the > > moon in Alt-Az-projection (because in >polar alignment I can't see the > > mathematical horizon) is already >displayed below the mathematical horizon. > > What is wrong here? > > >I don't understand- you said the moon was below the horizon at >00:15:00, so >what's the problem? ------------------------------------------------------------------ Sorry, my fault. I have to say that at this moment, the moon was just below the real mountain-horizon but obviously not yet below the mathematical one. But in CdC at this moment, it was already displayed below the mathematical horizon.
------------------------------------------------------------------ > > The difficulty is that I can't imagine to create a proper local >horizon > > with these obstacles - I mean, one evening the moon rises >above a mountain > > and on the following night the moon rises above the >same horizon but is > > displayed much below or above the already >created horizon line from the > > previous night. >Uh, sure. The moon rises at a different time each night. ------------------------------------------------------------------ Right again. But that's also not the problem. Ok, I sit behind my binocular and press the "Actual time"-button in the "Date/Time" settings as soon as the moon is completely visible or invisible. Now I can check the moons' Alt/Az-informations and do the calculations. So far no problem. I creat the horizon at this particular Az-location with the method I already described with the moons' radius. The next day, I wait about an hour or so later for the moon to appear. Ok, this will slightly be on another Alt/Az, but this lies within the 1-degree-Alt-accuracy of the horizon creation file, so the afterwards created horizon should be the same as the one from the night before. Now, the moon appears, I press "Actual Time", check the coordinates and look on the chart for a rough overview. The mathematical horizon is always visible. And when I compare the distance "math-horizon to real-created-horizon (from the night before)", the actual(!) nights' distance "math-horizon to new-real-horizon" varies enormously - meaning, the moon is much below or above the should-be-real-horizon, and sometimes even under the matiematical horizon(!) although it should be the same altitude as the created horizon from the night before. You see, the problem is not the different rising and setting of the moon, but it's display in SkyCharts. I strongly assume that this is because the precessional motion the ecliptic is simulated to do over only 24 hours. I send Robert a few screenshots about that. Hope I could make a few things more clear. Luzius --- In [email protected], John Mahony <jmmah...@...> wrote: > > ----- Original Message ---- > > > From: Robert Vanderbei <r...@...> > > > > I'm not sure I understand your questions. > > ... > > More comments below... > > > > On Jul 21, 2010, at 11:57 AM, luzius.thuerlemann wrote: > > > > > Ok, here my problems: > > > 1. when I want to see if there are other coordinate data in the > > > information > >board for the moon in Alt-Az and Ra-Dec, and let the software search for > >the > >moon in the toolbar, the coordinates are centered +00°00' and 24h00m00,0s > >(in > >polar projection). But the moon is on the other end of the sky. How to fix > >this. > > > > > > I'm not sure what you mean by "the coordinates are centered +00°00' and > >24h00m00,0s (in polar > > projection)". I guess you mean that you are in Alt/Az mode looking > > straight > >up, right? > > No, 0 deg 24h would be a point on the celestial equator. > > But I'm having a hard time understanding his questions, too. > > > > > 2. on the 21. July 2010 at 00:15.00 the moon completely disappeared > > > below > >the south-western mountain-horizon. When I simulate this time then the moon > >in > >Alt-Az-projection (because in polar alignment I can't see the mathematical > >horizon) is already displayed below the mathematical horizon. What is wrong > >here? > > > > I don't understand- you said the moon was below the horizon at 00:15:00, so > what's the problem? > > In v2.7x, you can make the ground semi-transparent. See the "chart > appearance" > settings. > > > > > The difficulty is that I can't imagine to create a proper local horizon > > > with > >these obstacles - I mean, one evening the moon rises above a mountain and > >on > >the following night the moon rises above the same horizon but is displayed > >much > >below or above the already created horizon line from the previous night. > > > > Uh, sure. The moon rises at a different time each night. > > -John >
