Celestron C9.25 SCT 9.25-Inch Schmidt-Cassegrain Optical Tube

The 9.25-inch SCT: the sweet spot between portability and aperture

The Celestron C9.25 SCT (C9.25-A XLT) is a favorite among experienced observers and imagers. Its 9.25-inch (235mm) aperture gathers over 1,100 times more light than the unaided eye, and its slightly slower primary mirror gives a flatter field and crisp star images across the view. The Schmidt-Cassegrain design folds a 2350mm focal length into a tube just 22 inches long and 20 lbs, a sweet spot between the portable C8 and the larger C11.

This listing is the optical tube assembly (OTA) only, so you can pair it with the mount that suits the way you observe.

Planetary detail and deep-sky reach

At its native f/10, the C9.25 delivers detailed, high-magnification views of Jupiter, Saturn, Mars and the Moon, with a theoretical resolution of 0.49 arcseconds. The extra aperture over an 8-inch pulls in fainter galaxies, nebulae and globular clusters. Celestron's StarBright XLT coatings maximize light transmission through the optical system for brighter, higher-contrast images.

Built for imaging: Fastar and HyperStar compatible

The C9.25 SCT is Fastar compatible. The secondary mirror can be removed and replaced with a HyperStar lens, turning it into a fast f/2 imaging system for wide-field deep-sky astrophotography with short exposures. You can also add Celestron's f/6.3 reducer/corrector for a wider field and faster focal ratio, or image at native f/10 for planets and the Moon.

Pair it with a modern mount

At 20 lbs, the C9.25 pairs well with today's strain-wave (harmonic drive) mounts: compact, light enough to carry in one trip, and able to handle a mid-size SCT without the bulk of a traditional German equatorial mount.

• Sky-Watcher Wave 150i: rated for 33 lbs without counterweights and 55 lbs with the Wave counterweight kit, and works in both equatorial and alt-az modes.
• ZWO AM7: rated for 44 lbs without counterweights and 66 lbs with them, leaving plenty of capacity for the C9.25 and a full imaging train.

Plan on using a counterweight. Strain-wave mounts can carry a lot of weight without one, but an SCT puts its center of mass well out from the mount. A counterweight balances the load, reduces strain on the mount and gives smoother tracking. The included Losmandy-style dovetail fits all of these mounts.

What's included

• Celestron C9.25 9.25" f/10 Schmidt-Cassegrain optical tube with StarBright XLT coatings
• Losmandy-style (CGE) dovetail bar
• 25mm eyepiece (94x)
• 1.25" star diagonal
• 1.25" visual back
• 6x30 finderscope

Celestron C9.25 SCT FAQ

What mount do I need for the C9.25?

The tube weighs 20 lbs before accessories, so choose a mount with comfortable capacity to spare, especially for imaging. The Sky-Watcher Wave 150i and ZWO AM7 are both good matches. Whichever mount you choose, use a counterweight for best balance and tracking. The included Losmandy-style dovetail fits most mid-size and larger mounts.

C8, C9.25 or C11?

The C8 is the most portable at 12.5 lbs. The C9.25 adds aperture and a flatter field at 20 lbs, and is often considered the best-corrected of Celestron's standard SCTs. The C11 offers the most light gathering at 27.5 lbs, but needs a larger mount. The C9.25 is the balance point for many observers.

C9.25 or EdgeHD 9.25?

The EdgeHD 9.25 adds flat-field optics and mirror locks designed for wide-field imaging with large camera sensors at native focus. The standard C9.25 costs less and excels at visual observing, planetary imaging and HyperStar imaging, where the HyperStar lens provides its own field correction.

Can I use 2" eyepieces?

Yes. Replace the included 1.25" visual back and diagonal with a 2" SCT visual back and 2" diagonal for wider fields of view with 2" eyepieces.

Specifications