Remove fts background

Download and install the latest version of Filestar.
Right click on one or more Fts file(s) on your desktop and select Convert with Filestar.
Type remove background in the search box.
Press Run.

What is .fts?

Name: Flexible Image Transport System
Extension: .fts
Format: Binary
Category: Raster Image
Developer: IAU FITS Working Group
Description: FTS file format is used to edit, store and transmit images with metadata (data with spatial and photometric calibrations) for scientific purposes. Most times it stores the data without the actual associated images.
MIME Type: image/fits
Sample: sample.fts
Wikipedia: .fts on Wikipedia