Had a look at this for the first time at Lostock through Andrew's 20". I was very impressed! I think Andrew used a UHC filter.
This is an object that I will have to hunt down in my SCT. I don't have any narrowband filters but it will be interesting to observe, nonetheless.
I remember Thor's Helmet being featured in A S & T a couple of months ago - it was mentioned that, in smaller scopes, it looks like a cartoon ducks head! I must admit this is what I first saw in Andrew's scope until I picked up the dimmer 'wing'.
