One Piece of the Puzzle: w-Projection

In my previous post I mentioned that w-projection might help the issues I was seeing with the sources on the very edges of my Cyg X-3 image. I’ve gotten to the point where I can use CASA’s imager on some sample Cyg X-3 data, and indeed it makes a difference.

Below are some zoomed-in images, with the cross representing the catalog position of DR 21. Here’s it without w-projection:

DR 21 without *w*-projection — [full size version](../../../wp/wp-content/uploads/2011/07/no-w.png).
DR 21 without w-projection — full size version.

And here it is with w-projection:

DR 21 with *w*-projection — [full size version](../../../wp/wp-content/uploads/2011/07/yes-w.png).
DR 21 with w-projection — full size version.

I believe that there are still issues to resolve regarding the hour angle dependence, but it’s nice to see the algorithm work so well for these particular sources.