proto-Lightspeed is an ultrafast CMOS based imager for the Magellan Telescopes. Here, we give a basic outline of the prototype instrument, which is mounted on the NasE port of the Magellan Clay Telescope. A detailed description of the instrument design, performance, and commissioning results is presented in Layden et al. (2026, submitted).
- Detector: We use the Hamamatsu Orca-Quest 2 qCMOS camera as the sensor. This sensor is exceptional in its read-noise and dark current performance, and the frame rates it can achieve. See the table below:
| Readout mode | Typical use | Noise level | Full-field speed | Small-region speed |
| Standard | Fastest possible imaging | Very low (0.41 electrons RMS) | ~200 images/sec | Up to ~6,600 images/sec |
| Ultra-quiet | Faint targets | Extremely low (0.29 electrons RMS) | ~50 images/sec | Up to ~1,400 images/sec |
- Optical design: the instrument uses a set of commercial lenses to re-image the telescope’s focal plane onto the detector. This allows us to adjust the image scale on the sky, depending on whether we want a wider field of view or finer spatial detail, while preserving image quality.
- Field of view and speed: proto-Lightspeed images a region of the sky about one arcminute across (roughly 1/30 the apparent diameter of the full Moon). It can take up to 200 images per second over the full field, and even faster when observing smaller regions, allowing us to capture rapid brightness variations.
- Filters and observing modes: proto-Lightspeed supports standard optical filters (g’, r’, and i’) as well as specialized observing modes. Its modular design allows additional capacities to be added as the development continues.
- Timing accuracy: exposures are synchronized using a GPS-based timing system. This allows us to measure when each image was taken with very high accuracy (at the tens-of-microseconds level), which is essential for studying eclipses and other fast, repeating signals.
- Software and data: proto-Lightspeed is operated using custom Python software. Supporting tools—such as exposure-time calculator—are maintained alongside the instrument and shared via GitHub.