[dkessler]

I'm trying to accurately simulate the sun at a specific location and time. I have a few questions that I couldn't find answers to in the documentation:

The longitude and latitude sliders in Maxwell only go to 40 and 100 respectively. My geographic location in Denver, CO is 104deg 59min W longitude and 39deg 45min N latitude. How do I enter this information in Maxwell?

What is the "sm" value?

Is the "Julian Day" value the day of the year numbered from January 1?

Is the "Hour" value the time zone from GMT? Anyone know what Mountain Time Zone in the United States would be?

Thanks,
Dan

[Josephus Holt]

The long/lat sliders definitely need some work. I enter the longitude w/the keyboard at 86 (beyond the slider's capability) and 36. It seems to work but don't really know if it's accurate. Hope this bug gets fixed w/the 1.0 release.

So far I've not been able to find out what the "sm" is for though I posted the same question a week or so ago. It seems to have something to do with the GMT time difference as it goes from -12 to +12. I leave it at zero and then set the GMT at local (Central Standard Time) -6hrs and it looks like that gives me the right time for where I am. (Mountain time would be your local MST -7 hrs). It seems to me a very complicated way to do this since by providing the long/lat we're already determining the time zone...would be so much easier the way FZ does it.

There are Julian day converters available on the internet, but it gives you a rather large number since it's counting how many days starting 4712 years ago. I just mentally calculate the "Julian Day" that I think Maxwell is asking for by multiplying the months by 30 and adding the day in the month. It may not be "right" on, but being a few days off either way should not make a noticeable difference.

[juan]

Hi Josephus and Dan,

As you said there are several things that must be improved in the usability of the sky settings (and other areas). In one week you will see a lot of new features, it is difficult you can imagine how many..

btw sm is the gmt time difference, we will make things easy very very soon.

Regards,

Juan

[Olivier Cugniet]

some snapshots, infos,.... what you want .....

[dkessler]

Juan,

Thanks for the reply. I'm looking forward to the release on the 22nd.

Dan

[R Paul Rogers]

The ´standard meridian´ is used commonly used in solar calculations to determine accurate ´solar time´ (as distinct from clocktime) at a particular location. If memory serves me properly standard meridians are every 15 degrees longitude starting at 0 (grenich mean). I do recall some sort of formula but the specifics escape me. I suspect there is some form of calculation in maxwell between longitude and standard meridian to determine accurate solar time for the accurate sky simulation. My feeling here is that unless you are interested in VERY accurate sun position you can leave both the longitude and sm at 0. Sorry for the brief explanation but my notes are half the world away . . . will post more when I catch up with them in a couple of weeks . . . hope this helps.