For NexStar 4 and for all C90 spotting scopes With these Celestron T adapters, 35 mm SLR cameras can be connected to the primary focus of the NexStar 4 or the C90 spotting scope. This allows you to take terrestrial photographs as well as lunar and planetary images. For deep sky photography you need an additional guide scope. In addition to the T-adapters, a T-ring is required for the respective camera.