Customer Reviews

Calendrical Calculations Millennium edition

5 star:		(6)
4 star:		(3)
3 star:		(1)
2 star:		(0)
1 star:		(2)

 

 

The first edition was a masterpiece, but this one is evenbetter! I've been involved in proof reading the new edition, and I'veread the final draft. There are lots of popular books out there about calendars and the history of calendars. Unfortunately, most of them are filled with mistakes, especially when they talk about non-European calendars. The purpose of this book is to both give reliable information about the different calendars and to provide software for calendrical computations. My own field is the Chinese calendar, and this is one of only two books that gets it right (the other is the Explanatory Supplement to the Astronomical Almanac). If you want to get the facts, there's no other comparable book. Remember to check out the web site of the authors to get the software and check out the applets. END

I highly recommend the book if you are interested in calendars as a hobby. If you are using this book for a project I suggest you look at this soley as a reference, since you will have to look elsewhere to have something you can use. The bibliography included is a good source.

The details and discussions of how they approach problems like the visibility of sunset are amazing and really opened my eyes to the difficulties of creating an accurate calendar under different systems. This book covers everything I could think of and quite a few ideas I would never consider.

I would give it 5 stars, except that the code and algorythms provided in the book are copyrighted and can not be used without explicit permission of the authors. I contacted the authors for a project I had, but it was determined that I could not use their algorithms since I intended to release under GNU license.

The previous review criticizes us for having a lengthy document reporting errata--but most of that document is not errata at all, but notes with extra material! C.U.P. introduced 10 spots where some lines were lost in the 2nd printing; when that was discovered they withdrew the printing and filled all orders with the hardback first printing.

Perhaps "anonymous" would have been happier if we did not share the details of errors with readers, but we feel it is in the reader's interest to have the errata open to public.

This books teaches you a lot of about the mathematics
that needs to go behind calculations to determine date/time,
and is truly a must-read book for people who want to
write such software.

However, I did find the equations hard to adopt for my
own use, partially because the pseudocode fails to show
exactly what the units were. For example, on the later
chapters where one must take into account planetary
position and such, it is extremely hard to find out
exactly what each variable/number represent if you're
not already very familiar with the subject. I believe
most of the definitions are in fact in the book *somewhere*,
but they are buried deep. This makes it extremely cumbersome and
time consuming for the reader to actually try to
implement the calculations.

If the notation can be improved a bit, I think it would
be even better book.

I bought this book, considering it the foremost authority on the subject of calendars and algorithms. While it does do an excellent job of explaining the calendars, and has good algorithms and is logical, a number of points I think should be dealt with, were not.

Firstly, lisp code, is not universal. I found it hard to adapt to lisp, and I have had to resort to the Java code which I am more familiar. I think the authors should have chosen non-specific coding routines, and shown more mathematical, intuitive ways of presenting the information. The presentation of the algorithms is somewhat cumbersome - especially the definitions.

Secondly, I deal with one calendar only, and my interest lies really, mainly with the Hebrew Calendar. I was disappointed that I had to refer to the Coptic Calendar for obtaining data for the Hebrew Calendar. It means I have to have code from both calendars, and I have to figure out what details I need from one system to the other. I would have liked to see each calendar dealt with as a totality in of itself.

Thirdly, The errata list is too long. The authors should present the corrections without all the added information (however useful). I'm not prepared to sift through a hundred pages looking for mistakes (especially minor ones), however interesting the added material maybe. It should be separately listed so I can easily refer to the critical mistakes if need be. I did note that there were very few critical mistakes.

Fourthly I felt the presentation of the algorithms were difficult to comprehend at first glance. Someone who is new to the field of algorithms, and presentation mathematically would find difficult to master. Was it not possible to simply state a definition and provide algorithmic reference, as opposed to viewing the function, knowing what it does, but not actually seeing the internal details of that function is very difficult to process.

I felt the reference system was not clear. I could not fathom why at some stages the authors did not mention their sources on a particular topic (with a proper endnote reference), in the text itself, and at other times, there was adequate references to the end notes. There was some confusion I had on whether the numbers were referring to footnotes, endnotes or actual numbers.

Otherwise it was a good summary of the overall calendars. And many points were raised and dealt with in a comprehensive manner. I would have liked an algorithm to process the Parshios (Torah Readings) for the Hebrew Calendar.

The authors make the code available, but it's not free. That is, you can't take the code and use it in your project, unless you get a license from them.

This was a big deal for me, which is why I'm giving it a one star review.

If the code was freely available, I'd probably give it 3-4 stars. I found the content frustratingly hard to decipher.

I have used this book and its predecessor for a number of years. The explanation of the algorithms is excellent. This book should definitely be used by anyone who has to write or understand date calculations.

I really enjoyed reading this book. The cod eis all in Lisp, which was my second computer language. If you need the algorithms in your code, be sure to check the web site for any errata.

Super! Better than the first edition: give it 6 stars.

History books that span the Middle East and Asia often mention that calendars other than the Common Era one are in use. The Muslim, Jewish and Hindu, for example. This book gives more diversity. It also describes the Mayan, Balinese, Bahai, Persian and Chinese calendars. It even mentions a calendar in vogue in France during their Revolution. While, when considering the Common Era calendar, the book shows how it differs from various Christian ones, like the Ethiopic and Coptic.

Though what really distinguishes the book is how it centralises a low of practical detail about each calendar. Most history books are written for a general audience. But this book is suitable for an astronomer or anyone else, who actually needs to implement one of those calendars. Very specialised text. Quite possibly addressing an unfilled niche.