Sky-Watcher 2″ Coma Corrector for Newton Telescopes
Anyone who has used a Newton telescope for astrophotography or visual observation will recognise the problem: stars in the centre of the field are sharp and pinpoint, but towards the edges they break apart into characteristic comet-like tails. This optical defect is called coma, and it is a natural result of the parabolic shape of the mirror. The Sky-Watcher 2″ Coma Corrector solves this problem at the source - it sits in the light path between the mirror and your sensor or eyepiece, and delivers evenly sharp images from the centre all the way to the edge of the field of view.
What is included
The coma corrector has a 2″ barrel, so it fits into any standard focuser without modifications. The package includes:
- The optical corrector element
- An adapter from the external thread to the 2″ barrel - designed for older Sky-Watcher focuser types
- A 2″ extension tube for visual observation
The corrector features an M48x0.75 thread, which is the standard used by the vast majority of astrophotography adapters today. If you plan to connect a DSLR camera, you will also need the appropriate T-ring for your specific camera mount - this is ordered separately according to your camera model.
Designed for fast f/5 Newton telescopes
This coma corrector is optimised for Newton telescopes with a focal ratio of approximately f/5. Fast Newtons of this type suffer the most visible coma, which is why the improvement is immediate - especially in wide-field astrophotography of nebulae, star clusters, and galaxies, where image quality across the entire field matters. Visual observers will appreciate the included extension tube, which allows comfortable focusing without any additional accessories. Photographers can use the M48 thread to connect directly to a camera or T-ring.
Technical specifications
| Parameter |
Value |
| Barrel diameter |
2″ |
| Thread |
M48x0.75 |
| Recommended focal ratio |
f/5 |
| Suitable for |
Newton telescopes |
| Use |
Visual observation and astrophotography |
| DSLR adapter |
T-ring required (ordered separately) |
Who is this corrector for
The Sky-Watcher 2″ Coma Corrector suits anyone who uses a fast f/5 Newton telescope and wants sharp stars across the entire field of view - whether for photographing nebulae and galaxies, or for comfortable visual observation with wide-field eyepieces. It is a practical and straightforward upgrade that makes a visible difference from the very first use.
