Ultratelephoto photography is easily achieved with your telescope and Sony NEX camera by purchasing this T-Mount Adapter for Sony NEX Digital Cameras. You'll need to take precautions to minimize vibrations, such as locking up the mirror if possible as well as using a cable release or remote control to fire the shutter.
First, remove the eyepiece. Next, attach the SLR camera adapter where the eyepiece would normally be attached to the telescope, and screw in this T-mount adapter to the opposite end of the SLR camera adapter. Now you can attach your camera to the T-mount and you are ready to begin taking pictures!
In addition to being used with telescopes, there are many old and new T-mount lenses which are installed to your NEX camera by adding this T-mount adapter to the rear of the lens and installing lens/adapter upon your camera.
Note: NOTE: Your camera will need to be in fully manual exposure mode, although some cameras may also work in aperture-priority autoexposure mode. Additionally, if there is a switch on the camera which chooses the focus mode, that switch must indicate manual focusing.