The all-sky 408 MHz map of Haslam et al .
is one the most important total-power radio surveys .
It has been widely used to study diffuse synchrotron radiation from our Galaxy and as a template to remove foregrounds in cosmic microwave background data .
However , there are a number of issues associated with it that must be dealt with , including large-scale striations and contamination from extragalactic radio sources .

We have re-evaluated and re-processed the rawest data available to produce a new and improved 408 MHz all-sky map .
We first quantify the positional accuracy ( \approx 7 arcmin ) and effective beam ( 56.0 \pm 1.0 arcmin ) of the four individual surveys from which it was assembled .
Large-scale striations associated with 1 / f noise in the scan direction are reduced to a level \ll 1 K using a Fourier-based filtering technique .
The most important improvement results from the removal of extragalactic sources .
We have used an iterative combination of two techniques – two-dimensional Gaussian fitting and minimum curvature spline surface inpainting – to remove the brightest sources ( \gtrsim 2 Jy ) , which provides a significant improvement over previous versions of the map .
We quantify the impact with power spectra and a template fitting analysis of foregrounds to the WMAP data .

The new map is publicly available and is recommended as the template of choice for large-scale diffuse Galactic synchrotron emission .
We also provide a higher resolution map with small-scale fluctuations added , assuming a power-law angular power spectrum down to the pixel scale ( 1.7 arcmin ) .
This should prove useful in simulations used for studying the feasibility of detecting HI fluctuations from the Epoch of Reionization .