Exercise

# Arithmetic with timespans

You can add and subtract timespans to create different length timespans, and even multiply them by numbers. For example, to create a duration of three days and three hours you could do:
`ddays(3) + dhours(3)`

, or `3*ddays(1) + 3*dhours(1)`

or even `3*(ddays(1) + dhours(1))`

.

There was an eclipse over North America on 2017-08-21 at 18:26:40. It's possible to predict the next eclipse with similar geometry by calculating the time and date one Saros in the future. A Saros is a length of time that corresponds to 223 Synodic months, a Synodic month being the period of the Moon's phases, a duration of 29 days, 12 hours, 44 minutes and 3 seconds.

Do just that in this exercise!

Instructions

**100 XP**

- Create a duration corresponding to one Synodic Month: 29 days, 12 hours, 44 minutes and 3 seconds.
- Create a duration corresponding to one Saros by multiplying
`synodic`

by 223. - Add
`saros`

to`eclipse_2017`

to predict the next eclipse.