I have an old Takahashi CN-212 convertible telescope from 1996. Heres the link to the manual: https://www.astropic...al_english.pdf
It says on page 17 that if you switch between cass and newt mode you will have to recollimate. That makes sense but what i'm wondering is do you have to center the spider in newtonian mode? On page 20 it talks about adjusting the spider in cass mode, but theres no mention of adjusting the spider for newtonian mode. Does this mean that once ive centered the spider in cassegrain mode, It should be fine for newt mode, and I just have to collimate the mirror?
More generally, say for a regular newtonian, does the spider have to be perfect centered? When I center the spider in cass mode, looking at the secondary mirror in newt mode it looks like the image i've attached where you can see one of the sides of the mirror since the spider isn't perfect, but does that matter?
I just want to know essentially if I have to center the spider every time I switch modes or if centering it in cassegrain mode is enough. Thanks!