Astro-Physics .76X CCD Telecompressor Corrector for 155 F/7A dedicated telecompressor for the 155 F/7 Starfire EDF telescope, this item was originally designed with the specific needs of CCD camera's in mind. However, it is more than capable of being used with any kind of camera- such as modern SLR and DSLR Camera's, or even Video Camera's, so long as the proper adapter is installed. It must be used with the 4" focuser- if your 155 F/7 EDF has the 2.7" focuser, it's a simple matter to upgrade to the superior 4". Optical performance involving this .76x CCD Telecompressor depends on a variety of factors, as follows: Firstly, it absolutely must be used with the 4" focuser. Secondly, the distance of the back of the housing to the image plane must be within 1 mm of ideal (80.8 mm +/- 1 mm). If this is an issue, there are adapters available sold separately. It is of further note that it is the optical distance, not the mechanical distance, that is being spoken of here. Please be sure that you have accounted for the indexing effects of your filters, sensor cover slips and any other glass in the light path. Thirdly, a UV-IR filter must be installed in the luminance channel in order to preserve the best possible image resolution into the corners of large formats. When used with the recommended custom adapters, the image is fully illuminated with the recommended cameras. Only 2" round filters will present a tiny, insignificant amount of vignetting in the very corners.
Basically- if you follow these general guidelines, it will perform at a top notch level when used with the 155 F/7 Starfire EDF telescope for imaging- no matter the kind of Camera, it can be adapted for use with this telecompressor.
Manufacturer Product Number: 155TCC