Which telescope to choose and some general questions I'm playing with the idea to buy a telescope for years now and finally decided to do so. There are two which I consider: 

The Celestron NexStar 127 SLT Mak and the Celestron NexStar 130 SLT

I already know the difference between a Refractor and Maksutov-Cassegrain and for which observations they're suited for best (and also that the Mak doesn't need collimating).

First question: Which would be the better choice for a beginner and eventually astrophotography?

Second question: Is it possible to buy just the tube later (so I can reuse the motors and the tripod)?

Third question: As I've read, the tripod is pretty wobbly, so is it possible to replace the tripod later on (or is there a norm for the mounts)?
Macs also need to be collimated, but much more rarely than Newtonians.
 They hold their alignment better (for more time).

For astrophotography you also have to think about the field of view each scope will give with the camera a that you will use and the fact that their mounts are not equatorial (less important if you are into planetary photography).

I see that the Mac has a Vixen dovetail, which means you can later use it on other compatible head mounts or put some other scope with the same dovetail type to the SLT mount.

It might be cheaper to wait more time and buy from the beginning the "right" equipment for your task, than buy something cheaper and then replace its parts.

Cheers!