Sky Rover 90 GPS 90mm f/6 Super ED Triplet APO PRO Refractor OTA

A 90mm f/6 triplet apochromat is one of the more useful telescopes you can own if you like to image. It's small and light enough to carry out and set up in a minute, fast enough to build signal efficiently in the hours the sky actually gives you, and — at 540mm — wide enough to frame large nebulae, clusters, and galaxy groups while still being sharp enough to enjoy the Moon and planets by eye. The Sky Rover 90 GPS is exactly that scope: an air-spaced triplet with a Super ED element, built to move easily between a camera and an eyepiece.

"GPS" is Sky Rover's General Purpose Stone series, and the 90 sits at the faster, wider end of it. Where the SkyRover 102 GPS is a 102mm f/7 at 714mm — a bit more aperture and reach — the 90 GPS trades a little of both for a faster f/6 focal ratio and a more compact, imaging-friendly package. If your nights lean toward wide-field astrophotography, the 90 is often the one you'll actually reach for.

It's a genuine APO PRO tube underneath, with the mechanics to match: a large 3.3-inch dual-speed focuser, a rotating Camera Angle Adjuster for repeatable framing, dual tube rings, and an extension tube in the box so you can set your working length for visual or imaging use.

Features

• 90mm f/6 air-spaced triplet apochromat. A true three-element air-spaced design with one FDC100 Super ED glass element for excellent color and contrast correction.
• 540mm focal length at f/6. Fast and wide for a triplet apo: efficient on faint deep-sky targets and generous enough to frame larger nebulae and clusters, while still delivering satisfying high-power views.
• Fully multi-coated (FMC) optics. Anti-reflection coatings on every air-to-glass surface for bright, high-contrast images.
• 3.3-inch geared dual-speed focuser. A large, stiff focuser with coarse and 10:1 fine control and a high-baffling drawtube that suppresses stray light. The drawtube carries M83×1 and M63×1 threaded interfaces and ships with a 2-inch eyepiece holder plus a 2-inch to 1.25-inch twist-lock adapter.
• Rotating Camera Angle Adjuster (CAA). Rotate a camera to frame a target and return to the same angle later — included, along with an extension tube to set your working length.
• Accessory-friendly dual tube rings. New dual-ring design with multiple side mounting holes for finders, guide scopes, and accessories, plus balance-bar mounting holes, a narrow astronomical dovetail, and a Vixen-compatible carry handle.
• Baffled aluminum tube, retractable dewshield. A machined aluminum tube with multiple internal baffles and a sliding dewshield that collapses for transport — about 402mm stored.
• Travels light. Roughly 4.8kg all-in (4.3kg for the bare tube), packed in a fitted soft carry bag.

The Optics

The heart of the 90 GPS is its air-spaced triplet objective built around an FCD100 Super ED element. Sky Rover is specific about the glass: it rates the Super ED element at an Abbe number of 95 or higher and is in the premium tier of extra-low-dispersion glass. Paired with a well-made three-element design, that's what brings the red, green, and blue focus points close together and keeps a bright star, a planet's limb, or the edge of the Moon clean and free of the colored halo a lesser refractor shows.

At f/6, the 90 GPS is deliberately faster than most triplet apos of its size. For imaging, that speed means more signal in less time, and the 540mm focal length frames the kind of medium-to-large deep-sky objects most wide-field imagers spend their nights on. For visual use, the same optics deliver crisp, high-contrast views with a sensible range of eyepiece magnifications.

Built to Be Used

The mechanics are where the "pro" in APO PRO shows. The 3.3-inch geared dual-speed focuser is a serious piece of hardware — large, stiff, and built to carry a real imaging train without sag, with a 10:1 fine knob for the last touch of focus and a blackened, baffled drawtube that keeps stray light from washing out contrast. Its drawtube offers both M83×1 and M63×1 threaded interfaces, so a flattener, reducer, or camera adapter threads on directly, and it ships with a 2-inch holder and a 2-inch to 1.25-inch twist-lock adapter for visual use.

Behind the focuser sits the rotating Camera Angle Adjuster. For imaging, it lets you frame a target and come back to the exact same orientation on another night; for visual use, it swings the diagonal to a comfortable angle. An extension tube is included so you can set the tube to the right working length for a camera or an eyepiece.

The mounting hardware is thought through the same way. Dual tube rings carry threaded holes on their sides for finders and guide scopes, there are balance-bar mounting holes for heavier imaging trains, a narrow astronomical dovetail mounts underneath, and the Vixen-compatible carry handle gives you a solid grip for moving the scope.

What It's Good For

The 90 GPS is, first and foremost, a wide-field imaging refractor. At 540mm and f/6 it frames larger nebulae, star clusters, and galaxy groups with room to spare, the fast focal ratio keeps exposures efficient, and the rotating CAA makes repeatable composition easy. Sky Rover offers a matched 1× field flattener and a dedicated 0.8× reducer for the 90 GPS; add the flattener for a flat full-frame field at native focal length, or the reducer to drop to a faster, wider system for the largest targets.

It's a rewarding visual scope, too. Ninety millimeters of well-corrected aperture shows the Moon in crisp relief, holds color on the brighter planets at high power, splits double stars, and pulls in the brighter deep-sky objects, while the wide 540mm focal length makes it a natural rich-field telescope for open clusters and the Milky Way with a low-power eyepiece.

An Honest Word on Fit

A 90mm triplet is compact but not featherweight — about 4.8kg with the rings and hardware — so it wants a stable mount: a solid photo or alt-az head for visual use, and a capable tracking equatorial if you intend to image. As a triplet, it also takes a little longer to reach thermal equilibrium than a doublet; give it time to cool on a cold night and it rewards you with its best images.

And while it's an excellent imaging telescope, it's a refractor first. For deep-sky photography you'll want the matched flattener or reducer, and the 90mm aperture is chosen for the bright and the wide rather than for chasing the faintest, smallest targets. Within that role — fast, portable, wide-field, well-corrected — it's hard to beat for the size.

What's Included

• Sky Rover 90 GPS 90mm f/6 Super ED triplet apo optical tube
• 3.3-inch geared dual-speed focuser with 2-inch eyepiece holder
• 2-inch to 1.25-inch twist-lock adapter
• Rotating Camera Angle Adjuster (CAA)
• Extension tube
• Dual tube rings with narrow astronomical dovetail plate
• Vixen-compatible carry handle
• Objective cover and retractable dewshield
• Fitted soft carry bag

Optional accessories from Sky Rover: matched 1× field flattener, dedicated 0.8× reducer, SR eyepieces, diagonal, erecting prism, and binoviewer.

Frequently Asked Questions

How is the 90 GPS different from the 102 GPS?
Both are air-spaced triplet apos in Sky Rover's GPS series. The 90 GPS is 90mm f/6 at 540mm — faster, wider, and more compact. The 102 GPS is 102mm f/7 at 714mm — a bit more aperture and reach. Choose the 90 for fast, portable wide-field imaging; choose the 102 for a little more image scale and aperture.

What glass does it use?
An air-spaced triplet design with one FCD100 Super ED element. 

Can I use it for astrophotography?
Yes — it's built for it. At 540mm and f/6 it suits a broad range of wide-field deep-sky targets, and the rotating Camera Angle Adjuster makes repeatable framing easy. Add the matched 1× field flattener for a flat full-frame field, or the dedicated 0.8× reducer for an even faster, wider system.

What size focuser does it have?
A large 3.3-inch geared dual-speed focuser with a high-baffling drawtube. The drawtube provides M83×1 and M63×1 threaded interfaces and comes with a 2-inch holder and a 2-inch to 1.25-inch twist-lock adapter.

Does it come with a diagonal or eyepieces?
No. It ships with the 2-inch holder and 2-inch to 1.25-inch adapter so you can add the diagonal and eyepieces that suit you. Sky Rover offers matched diagonals, eyepieces, and a binoviewer as options.

What size mount should I use?
It's about 4.8kg with the rings and hardware. For visual use, a sturdy alt-azimuth or equatorial head sized for a small refractor is fine; for imaging, use a capable tracking equatorial mount and include the weight of your camera and accessories when sizing it.

How compact is it for transport?
With the dewshield retracted the tube is about 402mm long, extending to roughly 550mm in use with the CAA and extension tube fitted. It packs in a fitted soft carry bag.

Final Thoughts

The Sky Rover 90 GPS is a fast, portable triplet apo that's just as happy behind a camera as behind an eyepiece. The air-spaced Super ED triplet — rated by Sky Rover at FPL-53-grade — supplies the color correction, while the big 3.3-inch focuser, rotating Camera Angle Adjuster, accessory-ready rings, and included extension tube make it easy to build the system around the way you actually image and observe. It isn't the largest or longest apo in the line, and that's the point: at 90mm f/6 it's the one you'll carry out on a weeknight, frame a wide swath of sky, and keep for as long as you own a mount to put it on.

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