In the beginning, you will find it beneficial to use list-directed formatting, rather than to specify formats yourself.
If you want to specify formats, read your Fortran documentation and make sure that the edit descriptors match your goals.
For example, F11.10 is not long enough to print the constant (approximately equal to Pi); ten digits after the decimal plus one for the decimal point uses up the field width of 11, leaving no space for the part to the left of the decimal. That is why asterisks were printed instead of the value.