Celestron CPC 1100 GPS Review Hands-On

Written by Zane Landers 2 years ago, for TelescopesToBuy.

Introduction

The Celestron CPC 1100 GPS is an absolute monster of a telescope, and probably isn’t best as a beginner or “only” instrument - but boy, does it deliver.

Celestron has been offering Schmidt-Cassegrains atop double-armed fork mounts since their inception in the 1960s, and the CPC series telescopes are the last remnants of that era. The CPC 1100 is the largest of the three aperture options in the CPC line, and Celestron doesn’t sell a 14” CPC for a good reason - these fork mounts are massive! The CPC 1100 is a very capable instrument, but between its price tag, weight, and complexity, you should probably own or have owned at least one or two other telescopes so you know what you’re getting into.

The C11 Optical Tube

The C11 has been around since the late 1970s when Celestron introduced a new telescope to fill the gap between the portable C8 and the observatory-class C14 (the C9.25 came much later). The C11 is an 11” (280mm) f/10 Schmidt-Cassegrain with a focal length of 2800mm, achieved using a spherical f/2 primary mirror and a convex, 5x magnifying secondary mirror. The Schmidt corrector plate at the front removes spherical aberration. The C11 focuses by moving the primary mirror along a rod inside the telescope; accessories and adapters screw onto the back. The secondary mirror can be removed to convert the telescope to an f/2 Schmidt camera with Starizona’s HyperStar system, enabling fast deep-sky imaging with or without an equatorial wedge. Various adapters, focal reducers, and accessories are available for customization.

The CPC Fork Mount & Tripod

The CPC mount is an alt-azimuth GoTo fork design, perched atop a massive steel tripod. To set it up, you simply place the tube/fork assembly on the tripod, align it with a few stars, and you’re good to go—assuming you can lift the 65 lb assembly. The mount’s GoTo and tracking are extremely accurate, allowing planetary astrophotography or short deep-sky exposures (under ~30 seconds) without a wedge. Adding a wedge converts the mount into an equatorial setup for long-exposure astrophotography, especially when paired with a focal reducer or HyperStar system. The mount supports Celestron accessories like StarSense Auto-Align and WiFi dongles for smartphone control.

The “GPS” part of the CPC 1100 GPS automatically updates time, date, and location. While GPS units may fail over time, this doesn’t inhibit telescope use, and a WiFi adapter makes GPS functionality redundant.

Accessories

The CPC 1100 GPS comes with a 9x50 finder, a 1.25” screw-on visual back, a 1.25” prism star diagonal, and a 40mm Plossl eyepiece yielding 51x magnification and a ~0.5° field of view. You’ll likely want additional eyepieces and a 2” star diagonal for a wider field of view. Fortunately, f/10 optics perform well with even modest eyepieces.

What can you see?

The C11 excels on most targets smaller than 1° across. Here’s what you can expect on Solar System objects:

• Mercury & Venus: Appear as featureless crescents or disks.
• The Moon: Stunning detail down to under a mile across.
• Mars: Polar caps, dark markings, and dust storms visible; its moons are a challenge but possible.
• Jupiter: Cloud belts, Great Red Spot, Galilean moons as disks with shadow transits.
• Saturn: Rings with Cassini Division; Encke gap and moons visible under excellent conditions.
• Uranus: Resolved disk with faint moons.
• Neptune: Bluish disk with its moon Triton.
• Pluto: Faint but detectable under dark skies.

Deep-sky performance varies by sky conditions. Under light pollution, you’ll be limited to bright clusters and nebulae. Under dark skies, the C11 reveals thousands of galaxies, resolves globular clusters, and shows nebulae like Orion in stunning detail.

Drawbacks

The C11 optical tube alone weighs 28 lbs, and with the fork mount it’s a 65 lb beast. Transporting or setting it up is a serious challenge. A dolly, garage roll-out, or observatory is strongly recommended. The long focal length limits field of view, and astrophotography requires a wedge (and is not beginner-friendly). Large objects like extended nebulae or clusters won’t fit in the field of view.

Conclusion

The Celestron CPC 1100 GPS is a massive commitment, but one that rewards you with lifetime capabilities. Its weight, cost, and size are daunting, but if you can handle them, it’s a powerhouse for deep-sky and planetary observing alike.