A few years ago I purchased a Celestron Nexstar 130 SLT computerised telescope thinking that it would be a perfect to get me into astronomy. The issue is the computer doesn't work at all and manually finding objects was a pain so I haven't used it in years. Now I want to get back into the hobby the 'proper' way by tracking objects with star maps and I want to get it right since photography and spectroscopy really excite me and that's what I want to end up doing. Despite all of this I can't seem to find a dovetail Equatorial mount that will fit my optical tube so now I feel I am stuck with a motorised mount that doesn't allow me to point my tube precisely and is really no fun. Is there any way for me to get into the hobby with my current optical tube using a different mount, use my computerised mount accurately enough for decent observation, or do I really have to buy a whole new optical tube just for the mount?
A Celestron Nexstar 130 SLT is not suitable for spectroscopy and the only photography that it will be mush use for would be afocal or DSLR imaging of the Moon (or Sun with a suitable filter).
For more serious work you will need a equatorial mounted scope with a better focuser.
Exactly which one to choose will depend of your budget and what you want to do.
When you say the computer does not work can you be more specific.