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I am thinking on grinding my own lightweight mirror (first f4 16", later f4 24"). The lightest and cheapest option is to get a thin blank and slump it in a decent kiln.
Anyone has longer term experiene with slumped mirrors? Overall doesn't seem to be more work than a normal (not pregenerated) blank.
Do I have to grind the backside as in case of normal flat back mirrors to avoid astigmatism? How do people support a convex back while grinding? Does it make sense to grind a hole in the middle for additional support? I am remotely considering a convertible Newtonian/Cassegrain system anyway...
Looking for a 12" DOB (or larger) which can be transported to Prestwick, Ayrshire. Any brand, as long as the telescope is optically sound and in good working order. I'm a reliable buyer who has bought and sold on this site before.
Can anyone confirm (or refute) - have I imaged Ganymede and Europa in orbit around Jupiter or is that just wishful thinking? (Only equipment used was a Lumix G7 with 150mm zoom lens - effectively 300mm with 2x crop factor - and of course a tripod).
It appears to be the case and yet I can't quite allow myself to believe it...
Thanks from an old newbie.
Looking to upgrade from my current 4.5" EQ reflector to an 8" Dob.
Not particularly concerned with brand and don't mind used condition provided all is in good working order.
Bundled accessories are a bonus (EPs and filters especially) though not a must.
Based in North Wiltshire and happy to drive to collect within reasonable distance (<1hr30).