dish diameter -> weight error

[TariqBlecher]

If one is unfortunate enough to have the DISH_DIAMETER set to zero in the antenna table, this will cause the WEIGHT column to be nan which will prevent imaging. Perhaps an error message somewhere will suffice...

[o-smirnov]

Arguably weight should be 0 in this case (a 0m dish will have infinite noise thus 0 weight), but if NaN is what CASA sets it to, then it is what it is...

We can't really put a sanity check on every input. When people try to do that, they invariably err on the side of over-restrictiveness, and only cause more complaints. A warning is ok, but I wouldn't call this a high priority fix...

[SpheMakh]

I can appreciate why CASA puts NaNs if dish size is zero. The WEIGHT column should only be populated if you set elevation and/or shadow limits, therefore having a non-physical dish size should lead to a NaN. If one specifies elevation and shadow limits they should make sure that the dish parameters are reasonable.

[SpheMakh]

Anyway you need to know the dish size to set these limits in the first place.