Co-mounting DSLR on AP rig? Any impact?

[NickK]

Still thinking about the 1100D and co-mounting this on the imaging rig.

For example - the EQ6 running with the Pentax+OAG+383L at 1340mm, then remove the A80Mf to run with a 1100D + lens piggy backed.

Although the mount will be targetting pretty much the same thing but a far wide FoV, will the 1100D make any movement (ie mirror movement) that will impact the AP rig running at 1340mm?