A meniscus corrector removes the coma of a fast Newtonian mirror
A plain Newtonian mirror at f/5 shows coma: stars away from the center of the field stretch into small comets. Dmitri Maksutov's thick, deeply curved meniscus lens, placed at the front of the tube, cancels most of that coma and leaves a field that is sharp across a camera sensor without a separate corrector.
The corrector does a second job. The diagonal flat is mounted on its inside face, so the tube needs no spider vanes. Stars come out round, without the four spikes a Newtonian adds, and less scattered light reaches the eyepiece. The secondary mirror can also be smaller than in a Schmidt-Cassegrain or Ritchey-Chrétien, which helps contrast on the planets.
The costs are weight and cool-down time. The meniscus is a thick piece of glass that must reach the night air temperature before the image settles, and a closed tube is slower to cool than an open Newtonian.
Sky-Watcher's Starlux 190 is the Maksutov-Newtonian you can still buy new
| Model | Maker | Aperture | Focal length | Weight | Price |
|---|---|---|---|---|---|
| Starlux 190 | Sky-Watcher (Synta, China) | 190 mm | 1,000 mm (f/5.3) | 29 lb | $2,375 |
| Quattro 200P (alternative) | Sky-Watcher (Synta, China) | 200 mm | 800 mm (f/4) | tube only | $925, plus coma corrector |
Prices are US list prices checked in November 2026. Special-order instruments are quoted by the dealer.
Russia's Intes-Micro and Orion's MN series, made by Synta, were the other well-known Maksutov-Newtonians; Intes-Micro models are now hard to find new and Orion closed in 2024. For imaging, most buyers now choose a fast Newtonian such as the Sky-Watcher Quattro with a separate coma corrector: cheaper and lighter, at the cost of diffraction spikes.
At 1,000 mm the Starlux 190 frames galaxies and globular clusters
On an APS-C camera with the Sony IMX571 sensor (23.5 x 15.7 mm, 3.76-micron pixels), the Starlux 190 at 1,000 mm gives a field of 1.35 x 0.9 degrees at 0.78 arcseconds per pixel. 100 of the 110 Messier objects fit in the frame, and 36 of them fill at least a quarter of its short side, among them M22 (Sagittarius Cluster), M67 (King Cobra Cluster), M101 (Pinwheel Galaxy) and M20 (Trifid Nebula).
Most backyard skies blur stars to 2 to 3 arcseconds. Image scales below about 0.7 arcseconds per pixel record no extra detail, so cameras on long focal lengths are usually binned 2x2.
Unlike most designs on these pages, a Maksutov-Newtonian is a fine visual telescope
The small secondary and absence of spikes make it one of the best planetary telescopes for its aperture, and its fast focal ratio still gives wide deep-sky fields. The reasons not to buy one are its weight on the mount, the cool-down wait, and a price about three times that of an 8-inch Dobsonian, which shows more deep-sky objects. See Newtonian reflectors and Maksutov-Cassegrains.