An Efficient Technique for making maps from Observations of the Cosmic Microwave Background Radiation

We describe a new technique for turning scans of the microwave sky into intensity maps. The technique is based on a Fourier series analysis and is inspired by the lock-in deconvolution used in experiments which typically sweep the sky continuously. We test the technique on computer generated microwave skies and compare it to the more standard map making technique based on linear algebra. We find that our technique is much faster than the usual technique and, in addition, does not suffer from the problem of memory limitations. Lastly we demonstrate that the technique works under real experimental conditions using observations of the moon.