First, what is the function of the aluminum sheet in your laminate? If you require fastening items to the laminate with threaded holes, you would have to be using fairly thick aluminum sheet to provide any useful thread, in which case the aluminum by itself is probably sufficient without being part of a laminate.
Having such a large surface area of aluminum sheet as a part of your laminate may result in problems with the part long before corrosion would be a concern. That problem being the large difference in CTE (coefficient of thermal expansion) between the carbon fiber and aluminum. For something like a telescope tube, the stresses in the laminate from the thermal expansion/contraction may be enough to affect the alignment of the optics, or may result in bond failure between the aluminum and the rest of the laminate.
As to galvanic corrosion, it’s definitely a concern between aluminum and carbon fibers, but mostly apparent when the area of contact between the two is exposed to an electrolyte. If the aluminum is completely encased within the laminate and no moisture is present, the corrosion will be extremely slow. Areas where you may have holes through the laminate exposing the interface between the carbon and aluminum, will be far more likely to corrode (but even then it would be very slow unless that area is exposed to high atmospheric humidity or a liquid electrolyte).
If this were my project, I would not use aluminum within the laminate. I would bond threaded inserts to the laminate where fasteners are required. This should be done in a way so that sufficient bond gap exists between the laminate and any surface of the metal.
Any time you want to use mechanical fasteners through a carbon fiber laminate, it’s best to “pot” the through holes with some kind of resin or adhesive to insulate the laminate from the metal.
