[X] My Assistant

[dmuller]

I tried to include some information on the current season of Mars into my realtime simulations (Mars clocks). Now one way of doing so that I can think of (but haven't really seen it around) is to calculate Earth equivalent dates for Mars, such that summer solstices are always on the "21-Jun" etc. Naturally these "days" (based on orbit around Sun rather than rotation of Mars) last about twice as long as on Earth (more precisely: 686.9 / 365.25 times as long). Using the only solstice I know (summer solstice 25 Jun 2008 ... Phoenix was there), this approach says that it would be 23 October on Mars now. Does that make sense? Is that useful?

[elakdawalla]

Also, Mars' elliptical orbit means that some seasons last much much longer than others. I have a page on the topic of Mars' calendar here. In brief, Mars' northern hemisphere spring is 194 days long; summer, 178; autumn, 142; and winter, 154. So there's some slosh of dates within the calendar. I'd take Earth calendar dates and turn them into solar longitudes, then convert from that based on Mars Ls to Mars dates.

My 2c.

--Emily

[mwolff]

Also, Mars' elliptical orbit means that some seasons last much much longer than others. I have a page on the topic of Mars' calendar here. In brief, Mars' northern hemisphere spring is 194 days long; summer, 178; autumn, 142; and winter, 154. So there's some slosh of dates within the calendar. I'd take Earth calendar dates and turn them into solar longitudes, then convert from that based on Mars Ls to Mars dates.

My 2c.

--Emily

In order to compare observations from different "Mars years", one can adopt a system similar to that used in some recent
atmospheric research. A web-calculator may be found at:

http://www-mars.lmd.jussieu.fr/mars/time/martian_time.html


The zero-point of such a system is obviously somewhat arbitrary. Using the convention of Clancy et al. (2000) and
the NAIF files -- naif0008.tls, de421.bsp, pck00008.tpc -- Mars year 1 begins at 1955-04-11 10:43:58.223 (to single
precision floating point for Ls=0). I have attached a file with the MY and Ls for each day at 0h00 UTC since Jan 1, 1955. Note
that this includes a "year 0" as an artifact for the period prior to the beginning of year 1. I have been told that this
is not a valid convention, but since I hadn't envisioned referencing observations from this period, I haven't fixed my
script (yet).

Attached File(s)

 marsyear_table.dat.gz ( 404.82K ) Number of downloads: 329