Thanks Anton!
Only in the Ha (orange) version - the CaK version is in the near ultra violet and taken with a 'homemade filter', this doesn't have the blocking filters that 'commercial' offerings have that make it safe for visual use. Reason I don't have the blockers the commercial filters do is to get the exposure nice and fast to freeze out the bad seeing, I was shooting at 1/2000s in the above pic. Most people can't see in CaK light anyway due to the natural yellowing of the cornea with age - in a properly blocked CaK setup I can just see a blue haze of a disk with the hint of spots... Generally it's only children and people who have had replacement corneas that can see in CaK light.
