The 48mm T-Adapter is the accessory of choice if you’d like to attach your full frame DSLR or astronomical camera to a Celestron EdgeHD optical tube. With DSLR CCD chips getting larger, Celestron created the 48mm T-Adapter to reduce vignetting and provide a larger light path to your camera’s sensor, producing exceptional astrophotos.

The standard comes with a 42mm T-Thread for a 42mm T-Ring. This smaller 42mm T-Adapter truncates the light cone coming from the back of the EdgeHD optical tubes, which creates vignetting in the corners of full frame imaging sensors. The 48mm T-Adapter has a larger T-Thread opening, allowing the unhindered light to illuminate the entire sensor, optimizing your full-frame sensor’s capabilities.

Below, you will find the difference between the 42mm and the 48mm T-Rings to give you an idea of the space the 42mm and 48mm T-Threads on the T-Adapter will provide.

Note: The 48mm T-Adapter will not offer any advantage to imagers with smaller APS-C sensors.  For this, Celestron still recommends the  and 42mm T-Rings for your specific model of camera. T-Rings are sold separately. See our 42mm or .

Celestron does not offer 48mm T-Rings, however, we do recommend the ones sold by .  They offer the most popular models for Canon, Nikon, and Sony cameras.

The chart below shows the relative illumination of the sensor in a 42mm and a 48mm T-Adapter. The X-axis is the distance from the center of the camera sensor.  The Y-Axis is the amount of light being received. As you can see, the 48mm receives more light than the 42mm T-Adapter and will reduce vignetting in your images.