This booklet contains correct instructions at last for achieving symmetry and great reliability easily for Newtonian secondary mirrors. Fifty pages have been added to its 4th edition to give the background story to the 5 years development and so end all the intuitive thinking for it is a curse that should be thrown away, then seek the scientific adjustments needed by the 90° change in the light path.
Not knowing they don't know they don't know how to collimate the diagonal secondary mirror, has consequently been a disease of all writers so far. Please see Sky at Night January 2018 page 94. The reviewer could not correct f3.8 optics permanently, whereas the determined author with a 12 years start on an f3.0 primary mirror became fully successful by 2013.
Page 50 of the 11th to 16th editions of Norton's Star Atlas & Reference Handbook to 1966. Arthur P. Norton B.A. prodded his students too politely into trying to prevent them falling in with the established intuitive methods by suggesting replacement of the two lateral adjusters with a hinged flat mount, leaving understanding until after carrying out the collimation, then enjoying the telescope. Any imagined need for lateral correction is subconsciously combined with gyroscopic rotation the reflection dictates. Pretending absence of the two lateral bolts, this book stops august 'thinks' from saying there must be three. Like reversing with a trailer attached, the arms need to do something opposite of what the brain is telling them is another analogy.
Thanks to the TLK of optics slower than f5 where such as an auto collimator works, it hardly mattered until this century that scientific instructions made no headway. Then in 2014 and feeling all alone, Norton's page 50 was inspected. Trawling the internet then produced R.F. (Bob) Royce. In The Ultimate Newtonian he replaces the INCORRECT and ILLOGICAL with one adjuster and a central bolt, as does Ed Jones Tracking Travelscope in Sky & Telescope Oct. 2010 by Gary Seronik. Conradhoffman.com/secondary mirror locks 'the dastardly pair' into strict slavery with said bolt; exactly what this book does for today's faster and better telescope optics.
The beginner cannot get into extremes of adjustment that shattered a mirror edge and damaged a bolt head by following wrong advice to try a laser collimator.
Buyers of the 4th edition subsequently complimented the instructions at the International Astronomy Show, Stoneleigh Park, Warwickshire. Two customers without money paid two months later for the 3rd edition. Another bought two more white film canister eyepieces (with the flange on the inside). Photo processors in town always keep them for coins in the charity box.
Finally, if primary mirror adjustment at the 4th stage does not produce perfect symmetry in a slightly off focus star, a single port laser collimator will set the secondary's vertical angle very accurately for such as close double stars and Jovian moons observing. A new telescope at first light may only need its secondary mirror correcting for what has not been guarded against sufficiently during transport. Rotation. Fast Newtonian secondaries need freedom to rotate.
Using the book will bring great satisfaction, but frustration for those who may still wish to collimate again and again and again!
Watch a presentation by the author below:
"'The Cave Collimator was excellent for my Maksutov–Newtonian telescope and very good for my Rumak–Cassegrain."
- Professor Ian Morison, Jodrell Bank
"Peter Clark's more scientific technique for Newtonian 'scopes works well and requires just a peephole eyepiece as the only gadget needed. I have used the method on my 6" and 10" telescopes with good results. I do not have either a Cheshire eyepiece or a laser collimator and having seen the latter used can appreciate the risk of an eyeful of laser beam! There is no electronic aid that can substitute for a sound understanding of how a Newtonian is constructed and set up."
– Christopher Eagleton, Beverley
Christopher's comment about the laser collimator is pretty fair for his two f 5 Newtonians, but by f 3.9 is proving essential for the increasing accuracy in vertical tilt needed by the secondary mirror. Laser collimators do not feature in my instructions until stage. Its beam will then be well within the secondary mirror diameter. Neither big bolt heads nor establishment writer could help the review of a 3.8 on p.94 of Sky at Night Jan 2018.
"I am currently converting old spherical f3 Newise mirrors to paraboloids for putting them into telescopes for wide angle work, using coma correctors. Naturally, collimation will be an issue so we will be making use of your work."
– Peter Wise
Peter is a recipient of the BAA's Horace Dall Medal for showing marked ability in the making of astronomical instruments.
It has been very reassuring to have journeyed from adjusting both mirrors at every session for 4 years to just the f/3 primary mirror slightly twice a year since 2013; mainly by eventually regarding the secondary mirror's two lateral adjuster bolts as like the handlebars of a bike. Correction by turning them can cause the rider to fall off by gyroscopic inertia. Similarly, adjusting a Newtonian telescope's two lateral bolts just because they are there causes a fall off from collimation achieved. Then sourced from ideas and trusted writers, lower grade compensation then produces a twisted light path fit for one temperature. The instructions chapter steers you clear of such disasters, rocking the boat and ruffling feathers on the way. Adjustments have become easy and reliable for any f ratio.
Slipping back into wrong methods again is actually prevented by the re-engineering support suggested in Norton's Star Atlas 11th and 16th editions from 1950 p.50. Then on the internet additionally there's Conrad Hoffman's secondary mirror holder* and in S & T October 2010, Ed Jones's Tracking Travelscope. They either don't fit the two lateral bolts or they lock them into being strict followers of the central bolt. Thus are instructions constrained into exactly the same method that scales up to the fastest optics as the author developed with words arising from his work alone before trawling for like mind support. Commercially, the principle of one adjuster (with slaves) falls foul of the establishment. There's nothing they'd claim three bolts are needed for that rotation about the central bolt doesn't perform more easily within the arc of concern at stage  and better for both medium and high magnification interests. Adjustments feel micrometer like with no hit or miss from 4 years into the task, even with the f 3.0 primary mirror of the main development 'scope.