Sky-Watcher Virtuoso GTi 150P Review: Editor’s Choice

The Optical Tube

The Sky-Watcher Virtuoso GTi 150P is a 6” (150mm) f/5 Newtonian reflector with a resulting focal length of 750mm.

Most f/5 Newtonians that I’ve tested usually have some coma at the outer edges of the field when viewed with 2” eyepieces, but 150P is limited to 1.25” eyepieces thanks to its design. So you’re unlikely to notice any coma. More problematic are the other edge-of-field aberrations, like astigmatism, especially when used with cheap wide-angle eyepieces.

Sky-Watcher claims to have added 94% reflective enhanced coatings to the optics in the Virtuoso GTi 150P. Provided that the coating works effectively across all wavelengths, it should add about 10% more light-gathering ability to the scope than a standard aluminum coating that has 89% reflectivity. Even though this is not supposed to be a huge improvement, I am hard-pressed to notice this difference at the eyepiece. Many modern reflecting telescopes’ optics already come with 92–93% reflective coatings anyway.

Still, the Virtuoso GTi 150P is different from most other 6″ f/5 Newtonian telescopes on the market because it has a collapsible strut tube that you have to unlatch and extend to put the optics at the proper spacing when using it. Provided the strut tube is fully extended, the pair of struts hold collimation pretty well during usage. Though regular collimation is required, this isn’t a big deal.

Due to the open tube, the Virtuoso GTi 150P’s mechanical design does make a couple of compromises. The openness of the tube means that stray light from nearby sources, such as streetlights or even the Moon, can get in. This is in addition to the general contrast loss from a light-polluted sky. Right across from the secondary mirror, I can see a small baffle as a partial solution, but this is not enough. My go-to solution to the stray light problems of the 150P is to construct a DIY shroud out of foam, which takes just a few minutes and costs nothing. This will also shield the optics from dew, bugs, dust, or curious hands.

The other weak link of the 150P optical tube is its 1.25”-only helical focuser. To keep the weight down, rather than providing a traditional metal Crayford or rack-and-pinion focuser, Sky-Watcher has gone with a simple helical focuser (essentially a giant threaded screw with a hole in the middle) made entirely out of plastic.

A Vixen-style dovetail rail is used to connect the optical tube of the Virtuoso GTi 150P to its mount. This means I could technically put the tube on another mount. But given the open-frame design and lack of rotating tube rings, I’d end up with the eyepiece in an uncomfortable position. The scope is also subject to mechanical flexure to work as a deep-sky astrophotography instrument, even though the optics are ideal for such.

Accessories

The Sky-Watcher Virtuoso GTi 150P comes with the same set of accessories as the Heritage 150P and 130P—a pair of 1.25” “Super” eyepieces of 25mm and 10mm focal length, yielding 30x and 75x magnification, respectively, with the 750mm focal length 150P.

The 10mm’s mere 75x magnification is hardly pushing the capabilities of the 150P’s optics. You’ll want a high-power eyepiece giving you something in the range of 100–200x for the best possible views of the planets, small deep-sky objects, and to split close double stars with the Virtuoso 150P.

With the Virtuoso GTi 150P, Sky-Watcher gives you a standard red dot finder powered by a CR2032. This finder is, of course, just fine for aligning the GoTo mount of the 150P initially, as well as manually aiming it, thanks to the huge field of view you get at low magnification.

Mount

Internally, the Sky-Watcher Virtuoso GTi mount shares little in common with the old, tracking-only “Virtuoso” mount that Sky-Watcher still bundles with their 90mm Maksutov (also formerly sold by Orion as the StarBlast AutoTracker).

The Virtuoso GTi is a tabletop Dobsonian (really a one-armed fork) mount with motors and clutches attached to both the altitude (up/down) and azimuth (left/right) axes.

You could turn the mount on, connect it to your smartphone or tablet, and then follow a simple alignment procedure with the free SynScan app or SkySafari. Following that, the Virtuoso GTi mount will automatically slew to tens of thousands of objects of your choosing and track across the sky.

I would recommend a bar stool or a milk crate to put the GTi 150P on, or alternatively, you can build a stand yourself for relatively little cost.

Should I buy a Used Sky-Watcher Virtuoso GTi 150P?

A used Sky-Watcher Virtuoso GTi 150P is unlikely to be very old, as these telescopes only debuted in 2022. However, be sure to check that the electronics work (though the telescope will work just fine without them). The lower part of the tube can be easily dented; small dents will not affect anything, and big ones can usually be hammered out.

Alternative Recommendations

The Sky-Watcher Virtuoso GTi 150P is, of course, my top pick in its price range, but I understand that some might want a different telescope with different capabilities, price, etc. So here are my picks. It should be noted that none of these telescopes are motorized or computerized; it’s a miracle that Sky-Watcher offers the GTi 150P at such a low price.

• The manual Heritage 150P, as well as the smaller Heritage 130P, are both great choices—and very similar to the GTi 150P—if you don’t want or can’t afford the GoTo upgrade.
• If you’re looking for a closed-tube tabletop Dobsonian to get around the inconveniences of a collapsible tube and required shroud, the Zhumell Z130 works great, though it has a smaller aperture than the 150P.
• The free-standing Orion SkyLine 6, Orion SkyQuest XT6, and Sky-Watcher 6” Classic Dobsonians are easier to collimate than the 150P tabletop scope and don’t need a table, but are significantly more bulky and suffer from a narrower field of view.
• For a bit more money, an 8” Dobsonian like the Apertura AD8/Zhumell Z8/Orion SkyLine 8, Orion XT8, or Sky-Watcher 8” Classic will blow a 6” scope out of the water in terms of viewing quality with the same portability factor as a full-sized 6” f/8 telescope. Celestron’s StarSense Explorer 8” Dobsonian also features computer-aided (albeit not motorized) pointing capability.

Aftermarket Accessory Recommendations

The Sky-Watcher Virtuoso GTi 150P can handle up to 300x magnification thanks to its whopping 6” of aperture and quality optics, but realistically, there isn’t much benefit in going above 200x or so. I would recommend you get a 6mm “redline” eyepiece for 125x magnification with the 150P, and if you must have a bit more magnification, a 4mm “planetary” eyepiece will yield 188x magnification. At this level of magnification, you’ll have no trouble resolving globular star clusters’ outer members, splitting tight double stars, or watching shadow transits of Jupiter’s moons.

While they certainly aren’t a cure-all for light pollution, a good nebula filter—particularly a narrowband, ultra-high-contrast (UHC) unit—can significantly shore up the contrast of bright nebulae under almost any sky conditions, making them a useful addition to your observing toolkit. We would recommend purchasing the 1.25” version of the Orion UltraBlock UHC filter for this purpose. It’ll greatly increase contrast on nebulae like Orion (M42), the Lagoon (M8), the Swan (M17), and bring out planetary nebulae at low powers so you can hone in on them at higher magnification more easily. Under decent skies, the UHC filter also allows you to see targets like the Veil or North America Nebula, which are very difficult to see with any telescope unfiltered due to their low contrast against even the natural background sky.

What can you see with Virtuoso GTi 150P?

The quality of your deep-sky viewing with any telescope is going to be heavily influenced by how light-polluted the skies are where you observe. As mentioned before, it’s very important to construct a shroud for the Virtuoso GTi 150P regardless of your sky conditions, but this is paramount if you have any significant light pollution; otherwise, the view will be washed out entirely.

The GTi 150P is great for looking at large open star clusters no matter what the sky looks like because it has a wide field of view. Objects like the Double Cluster in Cassiopeia or the Wild Ducks Cluster (M11) in Scutum are great targets, as is the famous Pleiades cluster (M45) in Taurus. You can also start to resolve the brightest globular clusters with the 150P, such as M13, M15, and M22, into individual stars under most viewing conditions, though you’ll need to use 100x magnification or more with the 150P to do so easily.

Under dark skies, the Virtuoso GTi 150P can also do a decent job of observing galaxies. You can see dust lanes in large, brighter galaxies like M31, M64, and M82, and you can tell that galaxies like M51 and M101 have spiral arms, though the arms themselves are just out of reach. The Virgo Cluster shows dozens of members, and numerous galaxy groups can be observed too.

Nebulae like Orion (M42) and the Lagoon (M8) can be seen under moderately light-polluted conditions with the Virtuoso GTi 150P, but the darker the skies, the better they’ll look. A UHC filter also helps bring out details and will reveal targets like the Veil, North America Nebula, or the Helix Nebula, which can be hard to see without a filter, even under dark skies. Small planetary nebulae like the Ring, Cat’s Eye, and Blue Snowball can also be seen; 6” of aperture begins to show the blue and green coloration in some of these objects.

The Virtuoso GTi 150P delivers excellent performance on Solar System objects too. You can easily see the phases of Venus, but you need a strong telescope and a clear night to see Mercury’s phases. Neither planet has any surface features that an amateur telescope can show. Mars shows its polar ice cap and any ongoing dust storms easily, while a few dark markings can be seen on its surface when the planet is close to Earth and conditions are good. You can, of course, see Jupiter’s moons easily at any magnification; high power shows their disks and dark shadows when they transit across Jupiter, along with Jupiter’s colorful pastel cloud belts, festoons, and the Great Red Spot. Saturn’s rings can be seen along with the razor-thin Cassini Division within them; its linear, dull cloud belts are visible; and a handful of dim moons appear around it as star-like pinpoints with the 150P. You can see Uranus and Neptune as fuzzy greenish and bluish splotches, but the GTi 150P lacks sufficient aperture to reveal any of Uranus’ moons, while Neptune’s moon Triton is a difficult catch. Pluto is just beyond the reach of a 6” telescope under dark skies, as it has receded from the Sun and continues to dim; by 2100, the icy world will be so distant that it will be beyond the reach of even most 12” telescopes under ideal viewing conditions.

Astrophotography with GTi 150P

As the Sky-Watcher Virtuoso GTi mount provides tracking, astrophotography with the GTi 150P is in fact possible – though you’re limited to the Moon and planets. Your smartphone will suffice for the Moon; for planetary imaging, all you need to do is get a functioning laptop and pop in a 3x or 5x Barlow lens along with a high-speed CMOS camera like the ZWO ASI224MC. You’ll be able to get great shots of Mars, Jupiter, and Saturn showing a bit more detail than you’re likely to be able to spot visually, especially with good seeing conditions and post-processing.