“With the help of the Guide I was able to identify this unusual net-like formation with some confidence as a Cirrocumulus lacunosus undulatus – that is, a collection of high, icy cloudlets forming a layer punctuated by holes – lacunas, if you like. Granted, that doesn’t tell us much of any real use, but still, it’s always nice to be able to put a name to something that’s been puzzling you.”

I like how you explained that. Very helpful. Thanks.

And yes, it seems very likely that the whole idea of angels was inspired  by tangent arcs! It’s also possible, as Gavin Pretor-Pinney argues in The Cloudspotter’s Guide, that much of the vision which is supposed to have inspired emperor Constantine was down to aerial spectra…

Nice to know that something so rough and ready could produce really quite satisfying results, though!

Of course, if I’d used a tripod the second step would have been unnecessary – I’d just have been importing the images into GIMP and then saving as a GIF straight away.