Peter, I like eat my humble pie served in an old hat with lashings of "Doh"
Cheers
Ok after taking a few more images with the iphone I find what I thought was Sirius B was actually a nearby star along roughly the same line. I was fooled into thinking it was Sirius B because the image on the screen looked very similar to what I could see at the eyepiece. Sirius B is actually drowned in the glare of Sirius on the iphone
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I'll keep trying for a real iphone Sirius B