How to align an alt azimuth to a comet?

[WilliamAstro]

I use a Celestron Nexstar 127 SLT and I am wondering how can I be able to align my telescope to the comet so I can photograph it?

[Paul M]

Assuming you have successfully aligned the telescope already, such that you are getting accurate GOTO's: 

Page 20 of the user manual explains how input user defined objects, select enter RA-DEC and manually enter the current Right Ascension and Declination for your chosen object. For Solar System objects those values change constantly so you need the correct value at the time of your observation.

I use SkySafari or Stellarium. For example here is what I get from Stellarium (in the info field top left) for Comet Atlas (Y4) at the time shown: