SwiftAA is a Swift / Objective-C framework intended to bring the best available implementation of the Astronomical Algorithms to the iOS and OSX realm. The goal of SwiftAA is to let anyone play with astronomical calculations easily. For that, a Swift Playground will be developed inside the project. More explanations will come in due time.


The licence of this software is the MIT licence. But it does not apply to the AA+ Framework, which retains its own licence. Quoting the original:

AA+ Copyright :

  • You are allowed to include the source code in any product (commercial, shareware, freeware or otherwise) when your product is released in binary form.
  • You are allowed to modify the source code in any way you want except you cannot modify the copyright details at the top of each module.
  • If you want to distribute source code with your application, then you are only allowed to distribute versions released by the author. This is to maintain a single distribution point for the source code.


The AA+ framework, written in C++ by PJ Naughter (Visual C++ MVP) is certainly the best and most complete implementation of the "Astronomical Algorithms", by Jean Meeus (purchasable from Amazon). To make the most of this code, you'd rather have a copy of the book with you.

As the author of the app iObserve (for Mac and iPad), I have myself worked a lot on implementing some of the AA algorithms for my needs. However, to push iObserve to the next level, I need to put a lot more work on these algorithms. And it is pointless (as well as very hard) to reach the fantastic level and quality the AA+ framework has already reached, after years of development and tests.

P.J. Naughter has kindly agreed to let me create a public repo with his code. My intention is to write a wrapper around it, to bring the AA+ framework to Apple's Swift realm (and Objective-C along the way). Pull requests will be accepted (if by any chance it happens) only about the Objective-C and Swift code. The AA+ code changes must be directed (as I will personnaly do if I need to) to the original source (see the AA+ website).

Image Credits: Y. Beletsky (LCO)/ESO