Anselmo,
Thanks for your interest in my book. The basic cost is $20 payable in US dollars. If you let me know where you live, I will let you know the shipping charge (airmail) including secure packaging.
I don't have access to Fer's algorithms so I can't comment on them but am confident that they are useful. However, I've programmed sundial analyses using martrices for at least 25 years. I started with programmable calculators which have the ability to perform marix algebra; this included the TI-59 and the HP-15 and 48S models. Around 1980, I started using the HP-86B computer, programming in the BASIC language. For my book, I mainly used the MATLAB language with my five year old Gateway computer. It has a great graphics capability.
Since I am unfamiliar with quaternions, I have not used them or am able to comment on them.
I think you will find my book interesting since it develops all relationships in a consistent manner.
I look forward to hearing from you.
Sincerely,
Harold
