Monday 18th Hacksaw Massacre! Director's Cut.

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Monday: Those of a nervous disposition should probably avert their eyes now: It seems I have been working with a measurement of 22cm or 220mm inside focus for the rear of the etalon band. It should of course be the magical and almost legendary 200mm or 20cm. Whichever floats your boat. I have no other explanation for the 22cm figure, wobbling about in my head, other than age, idiocy or failing memory. Or, probably, all three and more besides.

As I was admiring the shiny, new bit of kit I suddenly realized that I could use this 2" EP holder as my first line of support for my modified PST. It had the same thread as the removable nose-piece of the 60mm extension fixed irrevocably to my massive back plate.

Small gap [arrowed] where the rotating polarizing adapter is lifted slightly by having two 50mm filters stacked at the bottom.

So I dutifully re--checked the focus position and then measured inwards by the completely and utterly wrong 22cm. I even chopped another 20mm from the end of my old 6" f/8 Celestron! If I carry on like this the stumpy dewshield will be longer than the main tube! Dogh! 😳

Tomorrow is promised grey until the afternoon so I shall have to wait for a chance to find the focus using the sun.  If only that bloke didn't keep shortening the main tube it might have been worth [magic] marking the back plate with the distance to focus. There's nothing else for it: I'll just have to hide all his hacksaws from him!

I hereby promise [cross my heart and hope to die] not to shorten any more telescopes until I have a clearer idea of what [on earth] I'm supposed to be doing. Luckily I had been ploughing through the old modding threads on the Solar Chat forum and immediately discovered my [20mm] error. As they say: "It's not what you think you know. It's having no idea what you're thinking. Nor why.

Must try harder. D-

Click on any image for an enlargement.

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