more about making fulldome images from panoramas

My earlier observation about the panoramic image needing to be stretched 2.5 times vertically as a rule of thumb seems to be valid only for those pans which have exactly the same field of view as that particular pan! Trying out more panoramas, found that if the image appears vertically compressed after making the panorama, we need to crop the initial image by cutting off some of the top and bottom to make it more strip-like, then resize with stretching to a square shape, and then polar distort. The resizing to make a square is actually not essential, but it allows us to standardize on the image size as 2048x2048 etc. And conversely, if the image appears vertically stretched, add more sky at the top if cropping is not desired.

Then the pre-processing of the pans - the pan can be made straight with the help of the ruler by dragging it down in Gimp as mentioned at this page.