CaK Swathe 18th May

I tried stacking 2 barlows to get this image to get me at a focal length of about 900mm for this image, which is a 4 pane mosaic.  Given that I am using 40mm aperture, this is what Nyquists sampling theorem dictates should be a near perfect focal length for this setup at this wavelengtj of light,  I have to say looking at the image I have to agree and are certain this is a combination I will be using again to get mid scale CaK closeups.