If it is the Imaging Newtonian:
This is the Coma Corrector recommended for this scope:
This coma corrector has a back focus distance of 75mm ± 5mm.
The 2600MC Pro has a back focus of 55mm when used with the extension tubes supplied with it.
So you'll need to add an extra 20mm to achieve the correct back focus using an extension tube from this set:
This will ensure that the camera is held at the correct distance for the coma corrector to work optimally.