ZWO’s new ASI174MM camera uses Sony’s latest Pregius IMX174 CMOS sensor. It combines several features putting it high on the list for anyone wanting to capture spectacular lunar and solar images, high resolution planetary images at long focal lengths or even as an autoguider without worrying “will I be able to find a guide star?”
The main advantages of the Sony IMX174 chip are:
- Large sensor size of more than 13mm across the diagonal
- High quantum efficiency of 78% at its peak
- Very low read noise of only 6e
- Extremely fast frame rate – effectively freezing moments of steady seeing
- Global shutter and no fixed pattern noise
Sony IMX174 Sensor – big benefits
Prior to the release of the ZWO ASI174 cameras it was difficult to find a good camera capable of full disk images of the Moon or Sun. This is no problem with the ASI174. It’s sensor has a pixel array of 1936 x 1216 with 5.86 µm square pixels. This makes the diagonal measurement of the chip 13.4mm across.
The Image above shows the comparative field of view between the ASI120 camera and the new ASI174. Shot through a small refractor at 600mm focal length you can see the ASI174 will easily cover 0.5° of sky. It is now very easy to caputre full disk images of the Sun through many popular solar telescopes from Coronado and Lunt – no more mosaics required.
Quantum Efficiency and Read Noise
Another big benefit of Sony’s IMX174 chip is the high quantum efficiency coupled with very low read noise. This equates directly to better signal to noise. Even with very fast capture rates you will get more signal from your target and less contribution from reading off the sensor of the camera – in essence cleaner data resulting in better images!
For a few years now Sony’s highly regarded ICX618 CCD chip was a popular choice for planetary cameras. If we compare the new Sony IMX174 sensor to Sony’s ICX618 the news is good for both QE and read noise.
The quantum efficiency of the IMX174 is slightly more than 11% better with read noise of nearly half! (6e for the IMX174 vs 11e for the ICX618).
| Sensor |
1/1.2″ CMOS IMX174 (mono) |
| Pixel Array | 1936 x 1216 |
| Pixel Size | 5.86µm |
| Exposure Range |
32µs-1000s |
| Bit Depth | 12 or 10 bit output (12bit ADC) |
| ROI | Supported |
| Interface | USB3.0 |
| Adapter | 2″ / 1.25″ / M42X0.75 |
| Peak QE |
78% |
| Read Noise |
6e |
| Well Depth |
32,000e- |
| Max Frame Rate |
164fps (at full resolution – 10bit) |
Mechanical Drawing ZWO ASI174MM
