The allowed age range depends slightly on the selected grid and metallicity
 but is around 12.3 Myr and 20 Gyr. If the age is out of the limits,
 a message will show the age limits for the grid and metallicity selection.
 To download single isochrone, select the grid, metallicity
 and just type the required age in Myr.
 In case of multiple isochrones request, type Age1--Age2, step all in Myr.
 For example, typing 1000--2000, 100 will produce as output 11 isochrones with
 ages equal to 1000, 1100, ..., 2000 Myr.
 For reasons of computational time, the maximum number of isochrones downloadable in one go is 60.
 If a photometric system is not selected, the HR-diagram is provided by default.
 For pre-computed isochrones, please select grid, metallicity and
 click on "Pre-computed isochrones" link in the Age(Myr) section.
 The sampling for the pre-computed isochrones is:
  20 -- 100 Myr: Δt= 10 Myr
  100 -- 500 Myr: Δt= 20 Myr
  0.5 -- 1 Gyr: Δt = 50 Myr
  >1 Gyr: Δt = 100 Myr