Sagitta finally and beyond….. Hard hard work ..It’ll all be worth it – someday…and I can’t wait for the day to come.
120 Grit SiC hardly makes as much noise as 80…but it’s impact shows upon the glass and thats all that matters. Only boring part of the grinding process from now-on is that – the exciting part of checking the sagitta every half an hour is no more. The thrill of inducing anxiety in harshad’s mind that I’m way ahead of him is no longer there…But I’ll take this – as long as I’m inching toward finishing my mirror.
Talk about causing anxiety in harshad’s mind… I was the person who seemed to be getting anxious. My mirror seemed to have been terribly roughned up – especially at the centre..unlike harshad’s whose mirror seemed much much smoother than mine. Thanks to satya – for pointing out the root of the problem – That I switched from the off-centre chordial strokes to the centre-on-centre strokes too soon. A couple of hours of Off-centre grindign and I’ve improved with both the sagitta and the roughned up centre.
Satya was gracious enough to not only drop into my place and give us some feedback about the mirrors – but also gave me – whats called the “bible of telescope making” – “How to make a Telescope” – by Jean texereau for the keeping ( only a couple of days )…but thats way good enough for me.. I’m planning to get the useful sections of the book either Xeroxed or scanned.. This book’s just brilliant – a total telescope-dumbo’s guide to building scopes of world – class quality and optics.
It’s funny how valuable the human-element is in Telescope making – epsecially the optics.. Most reputed telescope makers putting up the caption “Hand-crafted optics” for their most expensive instruements…The supposedly “random-strokes” of the human hands providing amazingly precise curvature and creating accurately spherical mirrors. Whats funnier is the fact that – mirror grinding machines that have been created supposedly use no more technology than to emulate the human hands itself.
Still a good way ahead.. more grinding with the higher grits and polishing as well..a pretty laborious process…But no astro freak would abstain from taking the pain…all that counts is the peep you can have through the instrument two months later.