Saturday, October 18, 2014

Mars Time Notes

Ah, glad I signed up for this whole 'Mars Clock' thing. I thought it would be as simple.

No.

Some links:

http://www.giss.nasa.gov/tools/mars24/
Mars24, sorta kinda the source.

http://www-mars.lmd.jussieu.fr/mars/time/martian_time.html
Sol conversion applet and some milestone dates to check that things agree.

http://ssd.jpl.nasa.gov/tc.cgi#top
Another converter; Julian dates this time.

http://www.giss.nasa.gov/tools/mars24/help/algorithm.html
A conversion method with an example; this is what Mars24 implements.

What I'll probably end up doing is this:

1. A wake-up inital timing every day, where the RTC is used to calculate a Mars time (AMT? or whatever...).

2. An Arduino millis() timer with alternating counts of 1027 and 1028 ms per 'Mars Second', although there actually is no such thing as 'Mars Seconds', it's just for display purposes.

3. A 1 ms subtraction every two minutes

4. A final 36 ms subtraction every day, and it should be accurate enough.

Actually, I'm not sure about the daily adjustment... I might just let the system reset overnight during low solar power and then recalc the new start time every morning.

BTW: There are two other reasons I'm doing this:

1. Comet Siding-Spring has it's closest approach tomorrow. I'll probably forget while I'm doing errands. Boo.

2. The solar panel / charger / battery and all of the associated logic to manage power is identical to that planned for Rover6, and it's power management scheduling.

For now, that is all...

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