QHYCCD QHY5III678M Mono

Sony IMX678: An 8.4 MP Sensor with 2.0µm Pixels

At the core of the QHY5III678M is a Sony IMX678 monochrome sensor, offering a 3856 x 2180 resolution on a back-illuminated (BSI) sensor with 2.0µm pixels. QHYCCD's sample images with this camera include Jupiter and Saturn by Christopher Go, the lunar craters Clavius, Blancanus and Moretus by Philippe Cambre, and a solar prominence by Eduardo Schaberger Poupeau with a 60 mm Coronado SolarMax III double-stack.

The 1/1.8-inch format measures 7.71 mm x 4.36 mm, an 8.86 mm diagonal. In the review on QHYCCD's page, Luc Cathala notes that the larger sensor reduces the number of mosaic panels and the smaller pixels let him use a weaker Barlow than with the QHY5III178M.

0.57e- Read Noise and Deep Near-Infrared Sensitivity

The IMX678 sensor features a physically deeper photodiode structure, which dramatically increases its sensitivity to red and near-infrared (NIR) light. The sensor shows almost equal peak sensitivity to NIR light as to visible light. Luc Cathala, who images in infrared to combat turbulence, reports in QHYCCD's review that the 678 peaks between 650 and 715nm and loses only 14% out to 807nm.

• Low Read Noise: Read noise runs from 0.57e- to 3.3e-.
• High NIR Quantum Efficiency: The peak sensitivity to NIR light is almost equal to that in the visible spectrum; the included IR850nm pass filter uses that range.
• Full Well Capacity: 9,000e- per the specification table.

43 FPS Planetary Capture with a 512MB DDR3 Buffer

In planetary imaging, capturing a high volume of frames in a short time is essential to "freeze" fleeting moments of steady seeing. The QHY5III678M streams its full 8.4 MP resolution at 43 FPS in 8-bit mode. Like all QHY5III V2 cameras it has a 512MB DDR3 image buffer, which reduces the transfer pressure on the computer during planetary capture.

At 16-bit the full-frame rate is 22 FPS. With a region of interest, the camera reaches 85 FPS (8-bit) or 43.5 FPS (16-bit) at 1080 lines, and 140 FPS (8-bit) or 71 FPS (16-bit) at 640 lines. Luc Cathala reports 43 FPS at full resolution with no dropped images up to at least 5000 SER frames on his laptop.

A Sensitive 90g Autoguider with an ST-4 Port

QHYCCD makes the QHY5III V2 cameras planetary and guiding cameras. The QHY5III678M weighs 90g.

The ST-4 compatible guide port replaces the custom interface of the previous generation (the QHY5III178M used a 5-pin LEMO port), so a lost or damaged guide cable is easy and cheap to replace.

8mm & 17mm Back Focus for C-Mount, CS-Mount, and 1.25-inch Setups

The QHY5III678M features a flexible front-end design with two native back focus distances: 8mm and 17mm. The telescope interface is 1.25-inch, with CS and C-mount.

• 8mm Back Focus: Without the top adapter. The 8mm back focus of V2 cameras makes them easy to use with an OAG.
• 17mm Back Focus: With the basic top adapter, which has 1.25 inch threads for a 1.25 inch filter and swappable glass.
• C-Mount and CS-Mount Lenses: The package includes both a CS-to-C adapter and a 1.25-inch-to-CS adapter, for CS-mount and C-mount lenses; the swappable top glass lets you keep a filter in place even with a lens.

The Monochrome Advantage for LRGB and Near-Infrared Imaging

As a monochrome camera, the QHY5III678M has no Bayer matrix, so each of its 8.4 million pixels records all the light that reaches it, and colour comes from separate filtered frames such as LRGB. QHYCCD offers a 1.25-inch filter wheel adapter to connect a mono planetary camera to the QHYCFW3-S filter wheel.

Luc Cathala also notes in QHYCCD's review that other astronomers report good infrared results in solar imaging and on Venus's clouds, and that in the visible band you need to keep the IR-cut filter.

QHY5III678M vs. QHY5III178M: A Leap in Resolution and Data Stability

The QHY5III678M is the upgraded version of the QHY5III178M, which is now discontinued.

• Resolution: The QHY5III678M provides a major resolution increase to 8.4 MP, up from the 6.3 MP of the 178M.
• Pixel Size: The 678M uses smaller 2.0µm pixels compared to the 178M's 2.4µm pixels. This gives finer sampling at the same focal length.
• Image Buffer: The QHY5III678M has a 512MB DDR3 buffer, which the 178M lacked. The 678 also moves from the 178's USB-B 3.0 port to USB-C 3.2 Gen 1 and from a 5-pin LEMO guide port to ST-4.

QHYCCD All-In-One Pack: Native Drivers for ASCOM and SharpCap

QHYCCD provides a comprehensive All-In-One software pack to get your camera running quickly. It includes the system driver and ASCOM drivers, and SharpCap is included in the pack, authorized by SharpCap. Install any third-party capture software before the pack. The camera is powered over its USB Type-C connection; some notebook USB ports give less than 5V, which can starve the camera of power.

The pack also includes QHYCCD's EZCAP_QT for device tests and update management, and a WDM broadcast driver that gives a live signal to OBS and other live software.