|
Shame you didn't get a chance to make more progress, Colin. Very cool project and hopefully you'll get a chance to finish the job, even if it's not this year.
IMO parfocal is a meaningless term suitable only for marketing brochures. Filters that are "parfocal" on a f/9 RC scope may not be on a f/5 refractor or on a f/3.8 newt. It also assumes that you buy into the belief that anywhere in the CFZ is good enough...
Cheers,
Rick.
|