Strange star Mask

[Warren]

Whilst processing Ha data for NGC2032 I created a star mask.
It appears to have a regular banding pattern horizontal and verticle across the image.
It appears as shown in the photo see link.

http://www.flickr.com/photos/wazza1956/6778750210/

It appears in the Ha image and the S11 and O111 images but the banding is a different spacing or frequency in these images.
It dosn't appear in RGB or L images.

Camera QSI 683wsg
Telescope Takahashi TSA102 at F8 there is a IDAS Light Pollution Suppression (LPS) Filters in the image train about 75 mm form the other filters.
All Camera filters are Astronomik.
Image captured with Maxim DL 5
All processing in pixinsight.
Anyone have any Ideas what causes this banding

Regards
Warren

[Juan Conejero]

Curious effect. Try increasing StarMask's threshold parameter a bit when yo generate the mask. This should get rid of the pattern.

This pattern looks like aliasing due to rotation of noisy images. But in such case the pattern should be orthogonal, which it isn't. Could be some kind of filter interference?