Making composite images

Assuming that we have the H-alpha and [OIII] images Ha.fit and O3.fit. First of all, use rfits to read the .fit files:

Hafit = rfits('Ha.fit');
O3fit = rfits('O3.fit');
ha = Hafit.data;
o3 = O3fit.data;
imagesc(ha), imagesc(o3);

We also need to create a matrix that has 3 planes of the correct size

rgb=zeros([size(ha),3]);

Then we need to shift one of the images so that the structure is aligned. See Shifting Images for more details.

has=imshift(ha,nrow,ncol);

After aligning, we normalize the two images so that the values are between 0 and 1.

rgb(:,:,3)=imscale(has,100,250);

This rescales the shifted Ha image, and insert it in the last plane (the red).

We then store the normalized [OIII] image in both green and blue

rgb(:,:,2)=imscale(o3,150,350);
rgb(:,:,1)=imscale(o3,150,350);

Now we can display the image:

imagesc(rgb)