High frequency map making problem

[zuoshifan]

A relatively good map can be made in lower frequencies (e.g. 400-450MHz), but the map made in higher frequencies (e.g. 700-800MHz) is very pool with strong noise like stripes in it.
It seems that this problem is closely related to the pseudo-inverse of the beam transfer matrix.

[jrs65]

Indeed it is. The pseudo inverse produces a completely deconvolved map which means it can be very noisy (especially on small scales). To make something that looks better, try using one of the KL filters with a S/N cut off that should improve the quality of the map. I keep meaning to write a quick Wiener filtering map maker which should improve the quality even more.