Re: [Mars-sim-developers] Mars Society Website Link To Mars Simulation Project Needs Updating

[manny k. <man...@gm...>]

Hi Shaun,

I'm reading this page https://marscalendar.com/epoch at your site.

It's interesting you pick the Earth year of 1609 as "the mir 0" .

I suppose we want people to look back the rich history of the discovery and
exploration of Mars.

But I'm hoping to get users in mars-sim to get excited about the day of the
first human setting foot on Mars.

It wasn't possible to pick an arbitrary "mir 0" earth date/time in mars-sim
in the past but the changes just made in the codebase this morning (
https://github.com/mars-sim/mars-sim/commit/47627166eccccb6e60acac58deb1807f3c5c2257)
will enable a user to choose their own "mir 0" in reference to an Earth
date/timestamp in a xml file.

And yes it comes in very handy to use the vernal equinox (when L_s = 0) to
signify the beginning of a new year on Mars, unlike the calendar for Earth.

So, for now, based on some previous discussions (at
https://github.com/mars-sim/mars-sim/issues/23) in github and the table at
http://planetary.org/explore/space-topics/mars/mars-calendar.html,
we pin down the earth date "2028-08-17 15:23:13.740 UTC" as the beginning
of the "mir 0" in mars-sim, which is also the start date/time of the
simulation.

How and what tool do you use to figure out that on 1609-03-12 19:19:06 UTC,
L_s is ~0 ?

For us, we use the formulae from Goddard's site (
https://www.giss.nasa.gov/tools/mars24/help/algorithm.html) to numerically
compute the MTC hour from a given Earth date.

So I plug in "2028-08-17" and iterate a few times to pinpoint that at
15:23:13.740
UTC, I get MTC at 00:00:00.016 and Ls = 0.1991

I also plug in "1609-03-12 19:19:06" and run it through, L_s = -64.6 and
MTC is 07:05:35.889.
I wonder why ?

May the limitation is that it uses the Unix epoch (Jan. 1, 1970) and I'm
wondering if it may have inherited inaccuracy on any dates before 1970. See
log below :

Regards,
Manny

2018-07-06T15:43:11.2 (Info) ClockUtils : 0000-Adir-01 corresponds to
Thursday, March 12, 1609 at 7:19:06 PM Coordinated Universal Time
2018-07-06T15:43:11.2 (Info) MasterClock : millis is 0.0
2018-07-06T15:43:11.2 (Info) MasterClock : jdut is 2440587.5
2018-07-06T15:43:11.2 (Info) MasterClock : T is -0.3
2018-07-06T15:43:11.2 (Info) MasterClock : TT2UTC is 43.55486
2018-07-06T15:43:11.2 (Info) MasterClock : jdtt is 2440587.500504107
2018-07-06T15:43:11.2 (Info) MasterClock : j2k is -10957.499495892785
2018-07-06T15:43:11.2 (Info) MasterClock : M is -322.56978481237
2018-07-06T15:43:11.2 (Info) MasterClock : alpha is -71.76445574841273
2018-07-06T15:43:11.2 (Info) MasterClock : PBS is -0.0020916183542698925
2018-07-06T15:43:11.2 (Info) MasterClock : EOC is 7.143943103500425
2018-07-06T15:43:11.2 (Info) MasterClock : v is -315.4258417088695
2018-07-06T15:43:11.2 (Info) MasterClock : L_s is -64.6384944020374
2018-07-06T15:43:11.2 (Info) MasterClock : EOTDegree is -9.41116747438453
2018-07-06T15:43:11.2 (Info) MasterClock : EOTHour is -0.6274111649589688
2018-07-06T15:43:11.2 (Info) MasterClock : EOT_Str is -00:37:038.68
2018-07-06T15:43:11.2 (Info) MasterClock : MTC0 is 7.093364987755194
2018-07-06T15:43:11.2 (Info) MasterClock : MTC1 is 7.093302587512881
2018-07-06T15:43:11.2 (Info) MasterClock : MTC_Str is 07:05:35.889


On Thu, Jul 5, 2018 at 10:52 PM Shaun Moss <sh...@as...>
wrote:

> Hey Manny, thanks for the email.
>
> There shouldn't be too many differences between the two clocks. Both use
> mils. There are different day and month names. Both start the year at the
> northern vernal equinox (Ls=0) but mine starts in 1609 so the dates should
> be the same, offset by a constant number of years.
>
> I think Scott Davis wrote the original timekeeping code in mars-sim. We
> met in 2000 and I introduced him to my calendar and clock back then.
>
> I will update the link. Thanks!
>
> If you have any questions about Mars timekeeping, please feel free to
> email or message me.
>
> Shaun
>
>
>
>
>
>
> On 6 July 2018 at 10:08, manny kung <man...@gm...> wrote:
>
>> Hi Shaun,
>>
>> Recently I've been refactoring the code that does the job of timekeeping
>> in mars-sim in hope of removing the limitation of having the default start
>> date (2043 Sep 30 00:00:00 UTC) at the beginning of a simulation.
>>
>> In light of that, we just put up a new Mars Calendar wiki page at
>> https://github.com/mars-sim/mars-sim/wiki/Mars-Calendar. May be you can
>> make use of this link somewhere in your website instead of the old link.
>>
>> Now that I spend more time reading about Mars timekeeping, it turns out
>> the version that we use in mars-sim is quite different from your Utopian
>> Calendar.
>>
>> Do you still by any chance know those who designed the timekeeping code
>> in mars-sim and whom you might have conversation with in the past ?
>>
>> Anyway, I notice that we use different names for week day names and month
>> names than in your Utopian Calendar. Also, we use 1000 millisols as the
>> time division for each day on Mars.
>>
>> Also note that our project website is with github at
>> https://mars-sim.github.io and not with sourceforge anymore
>>
>> Regards,
>> Manny
>>
>>
>>
>> On Sun, Apr 30, 2017 at 4:34 PM Shaun Moss <sh...@as...>
>> wrote:
>>
>>> Sure, no problem.
>>>
>>>
>>> On Sun, 30 Apr 2017 at 18:33, manny kung <man...@gm...> wrote:
>>>
>>>> Awesome !
>>>>
>>>> Do you mind updating the link on your webpage to
>>>> https://mars-sim.github.io ? We've just moved our project to GitHub.
>>>>
>>>> I was going to say that VR goggles has the potential of making the
>>>> virtual world more immersive than ever. For sure future Mars settlers will
>>>> make use of some forms of telerobotic rovers/flyers to explore the surface
>>>> of Mars.
>>>>
>>>>
>>>> On Sun, Apr 30, 2017 at 9:18 AM, Shaun Moss <sh...@as...>
>>>> wrote:
>>>>
>>>>> Hey guys
>>>>>
>>>>> Latest version of the calendar is at http://marscalendar.com with
>>>>> some links to Mars Simulation project.
>>>>>
>>>>> Please let me know if you find any issues.
>>>>>
>>>>> Shaun
>>>>>
>>>>>
>>>>>
>>>>> On 9 April 2017 at 09:19, Shaun Moss <sh...@as...>
>>>>> wrote:
>>>>>
>>>>>> The link will be http://marscalendar.com but I have to pull my
>>>>>> finger out and set up the site :) I will do it now.
>>>>>>
>>>>>> Scott and I met back in '99 in Toronto iirc and he was working on
>>>>>> Mars Sim then, so I am happy to hear it is still going strong!
>>>>>>
>>>>>> Shaun
>>>>>>
>>>>>>
>>>>>>
>>>>>> On 9 April 2017 at 02:29, manny kung <man...@gm...> wrote:
>>>>>>
>>>>>>> Hi Shaun. thanks for being responsive! I'd definitely love to see
>>>>>>> any new changes you've since made. Yes for now, if you have a link, I'll
>>>>>>> post the url in a help page in mars-sim. I can incorporate any updates to
>>>>>>> the Mars timekeeping into mars-sim if you don't mind. Regards, Manny
>>>>>>>
>>>>>>> On Fri, Apr 7, 2017 at 8:54 PM, Shaun Moss <
>>>>>>> sh...@as...> wrote:
>>>>>>>
>>>>>>>> Do you just want to link to it? I can put it online over the next
>>>>>>>> week or so. I was going to wait until the book (which will include the
>>>>>>>> updated calendar) is done but that will take months.
>>>>>>>>
>>>>>>>> Shaun
>>>>>>>>
>>>>>>>>
>>>>>>>> On 6 April 2017 at 03:49, James Burk <jb...@ma...> wrote:
>>>>>>>>
>>>>>>>>> Adding Shaun to thread...
>>>>>>>>>
>>>>>>>>> On Wed, Apr 5, 2017 at 11:16 PM <la...@na...> wrote:
>>>>>>>>>
>>>>>>>>>> I'm connected to Shaun Moss on Facebook. I'll go ask him :-)
>>>>>>>>>>
>>>>>>>>>> - Lars
>>>>>>>>>>
>>>>>>>>>>
>>>>>>>>>> <https://marscalendar.com>
>
>