*** I qualify as a carpal tunnel because my quantity always beats my quality *** Amateur astronomer - Sirius Hobbyist! Jackie Borg 125SD 6" achro w/ Jaeger lens 4" LZOS CF 105/650 DM-6 & Tri36L Ethoses, Pentaxes, BGOs, Naglers, Pans,etc Garrett 100mm Mk II
Active instruments: 4.25" f/6 Newtonian on altazimuth Springfield mount with crutch tripod -- telescope for the handicapped. 12" f/6 Newtonian Telescope maker since 1958; always more to come? Well maybe just one more and it will be something very special Stellafane Awards: 1977 1st award for 4" f/6 refractor 1978 1st award for 4" f/4 Lurie Aplanat 1983 1st award for Newtonian smoking pipe For Sky and Telescope articles, please see Bio info.
Quote:Does it really matter in terms of balancing, collimating, etc.
Quote:I am toying with many possibilities in a Dob right now from getting new to buying a mirror and having the structure built for me.One issue is keeping the eyepiece at zenith close to 5' 8" or so. I am thinking ultralight and a mirror of 1" or less (already have two good candidates in the 14" -15" range). Is the difference between a focal ratio of f/4.5 pretty inconsequential versus a 4.8 except maybe for a small difference in eyepiece height? Does it really matter in terms of balancing, collimating, etc. I guess I am leaning towards a 4.8 hoping I might not need a paracorr.