Tucsen microscope cameras in astrophotography
Tucsen is a Chinese company making microscope CCD and CMOS cameras (site 1, site 2). In Great Britain some of them are sold by Opticstar as astronomy cameras. They also provide Nebulosity and Maxim support for those cameras.
Tucsen CCD cameras have 12-bit dynamic range (used Sony CCDs can't really use 16-bit A/D), active cooling and they can do long exposures. The 12-bit A/D makes them also faster than 16-bit Atik or QHY camera with the same CCD.
Most interesting is TCC-6.1 (Opticstar DS-615C XL) equipped with big APS-C size color CCD - ICX413AQ. The same sensor is used in QHY8. If you want a color upgrade to a DSLR this model may be the answer. Tucsen also has few more color cameras with big sensors. They have much smaller pixels and can be used with lenses or short focal lengths (small refractors). There is also few mono models, one is equipped with ICX285 (Atik 314L+, QHY2Pro). This camera may be an alternative to those Atik/QHY models as well as quite handy lunary cameras (as it's faster).
If you want to find the best price for Tucsen cameras try finding their local reseller or partner. You can also send an email to their support, and they will redirect you to the closest reseller... Check what software they provide, and which revision of given model they have - standard software has all the features but it's not astronomical software so you won't get FITS files for example. There seems to be few revisions of Tucsen cameras (from black housing to blue). They differ in cooling power or sometimes maximum exposure time. Some cameras may be supported in Nebulosity by choosing matching Opticstar camera name (not checked).