If "servo" equals "rc servo" -> bad idea. Use a closed loop stepper or a closed loop geared dc motor with encoders - which is alo called "servo", but not "rc servo"
Those type of questions can only be answered by you. How do YOU want to do the attachment? How fast do YOU want the mechanism to turn? How do YOU want to attach a motor to the telescope? How do YOU want to power the motor?
We need to see your schematic and your code at the very least.
We can only know what you tell us, and what you are telling us is just too vague to make any sort of accurate answer possible.
For example, is the movement to track the sky? If so we need to know what the telescope mount is. Normally you would need two motors to move the telescope anywhere in the sky.
Well, the quest it's quite well defined. Problem is, if you are not familiar with telescope mountings you have a hard time understanding it. If it's a school project then you would just use the equatorial mount and compensate for time --> 24h == 1 turn. You'd still dial in the coordinates of the object you are interested in manually but the tracking would be automatic --> best for taking fotos. In earlier days this job was done by using a syncronous motor + gearbox, so no uC but mains power supply.
Programming microcontrollers is a lot like writing a paper for language class; you must ask and answer the questions "Who, What, Where, When, How, and sometimes Why" (wait... a,e,i,o,u... sometimes y... still stands). For programming microcontrollers, you need Idea (in words and drawing), Devices (the hardware you will use), Schematic (wiring+wireless diagram connecting all devices), Code (the instructions for the microcontroller to employ the devices).
Here is a link to a plain "r" telescope. Use it to help define, explain and create your telescope.