# Is my calculation of the current day/sol of current Mars month accurate?

I'm working on providing Mars related data for a project. I'm using 2 points of data that are available to me from Rover Environmental Monitoring Station at the Centro de Astrobiologia.

The 2 data points provided to me are the following:

• Month as of May 1 is 7.
• Solar Longitude as of May 1 is 195.

Other known data points for this:

• Month 7 starts on Sol 371.9
• Month 7 ends on Sol 421.6
• Month 7 starts at solar longitude of 180
• Number of sols in month 7 is 49.7

How I do it:
Product of starting sol of month 7 and current solar longitude (371.9 X 195).
Divide that by starting solar longitude of month 7. Previous step divided by 180
Multiply by number of sols in month 7. Previous step multiplied by 49.7.
Divide by last sol of month 7. Previous step divided by 421.6
Result: About the 40th sol in month 7.

• Please clarify your specific problem or provide additional details to highlight exactly what you need. As it's currently written, it's hard to tell exactly what you're asking.
– Community Bot
May 1 at 23:00
• This Wikipedia entry shows there are several proposals for a Mars calendar, so you should probably first start with nailing down which one you're interested in. en.wikipedia.org/wiki/Timekeeping_on_Mars May 2 at 4:16