The QHY45GX is a 4 megapixel cooled CCD camera using a 2K x 2K KAF-4320 CCD with 24um pixels. It is small in size and highly integrated in internal electronics, just 10cm in diameter. The effective photosensitive area is 50 x 50mm. It has a two-channel readout mode, low readout noise, fast image download speed and an ultra-low noise switching power supply. The computer interface is a highly stable Gigabit network data interface with transmission distance up to 100 meters. Liquid cooling eliminates heat turbulence exiting the camera.
The circular design of the QHY45GX is very suitable for large field, prime focus imaging. The QHY45GX realizes sensor and circuit overall cooling. Liquid cooling dissipates heat without producing external heat turbulence. The water-cooling design avoids heat convection around the camera caused by exhaust fans, thereby avoiding affecting the prime focus near the entrance pupil. The liquid cooling design also avoids any vibration that might be generated by a cooling fan.
The QHY45GX sensor is 2k x 2k at 24um. The pixel size makes this camera ideal for long focal lengths. They also provide a generous 500ke- full well capacity for great dynamic range without relying on non-linear transfer of charge to avoid saturation of bright stars.
The QHY45GX uses a high stability GigaE Gigabit Network for data transmission. Transmission distance can reach 100 meters. Longer distance, anti-electromagnetic interference fiber transmission can also be achieved through Gigabit-fiber optic repeaters
In response to the special needs of the largest optical telescope in China (LAMOST), a joint project of the Shanghai Astronomical Observatory and Lightspeed Vision (QHYCCD) of the Chinese Academy of Sciences successfully researched and developed over three years this new cooled large target CCD camera, the QHY45GX. With 4 units installed at LAMOST and 4 more planned, the camera has proven its excellent performance and established that locally engineered and designed high quality instruments can compete on the world market.
QHY45GX has a large effective photosensitive area (50mm*50mm), 2K*2K resolution, and fast image download speed. With a round design, it is ideal for large field of view primary focus imaging.
The entire imaging array is read from four channels, each driven by a low impedance two-level source follower that provides high conversion gain. This combination enables low noise at a net readout rate of 12 MHz (3 MHz per output).
The KAF 4320 image sensor, a high performance monochrome area array CCD, is designed for a variety of image sensing applications. The sensor uses true two-phase CCD technology, which simplifies the support circuitry required to drive the sensor and reduces dark current without compromising charge capacity. The sensor also utilizes the TRUESENSE transparent gate electrode to increase sensitivity.