[Outcast (Carlton)]

I have an ongoing focussing issue with my Meade Series 5000 80mm APO & I am very confused.

Bought the Meade second hand a few months ago & then purchased a range of eyepieces. The Meade comes with a 2" Meade diagonal & adapter to take 1.25" Eps.

Originally, I purchased a GSO Superview 20mm 1.25" EP (among others) but, could not get it to come to focus; not enough inwards travel on the focus tube.

I then exchanged it for a GSO SV 15mm 1.25" EP, tested it & achieved focus in the 2" diagonal. Problem solved, or so I thought.

Tonight I had the scope out & for reasons completely lost on me, I cannot get the 15mm GSO SV to come to focus; not enough inwards travel.

How can this be??

I simply don't understand what is going on here & it is messing with my head big time!!

Interestingly, a cheap HM25mm EP I have from a department store refractor comes to focus fine however, it is considerably smaller in construction than the GSO. All my other EPs work just fine.

Out of interest, the 15mm EP comes to focus just fine when used without the diagonal.

Could there be an issue with the focusser?

Could there be an issue with the diagonal?

Is this just an issue with these particular EPs design?

Should I switch to a 1.25" diagonal to shorten the light path?

Has anyone else had these issues with a refractor?

There is a huge amount of focus travel but, with the diagonal attached, the majority of my EPs only use the first cm or so of travel. Is this normal?

Can anyone help me out here please?