Reviewing the Optical Tube Of Orion XT6
The XT6 – and its Plus variant – is a 6” f/8 reflector, a common standard of telescope for the past century.
If you went to Stellafane in the 1920s, what design made up the vast majority of homemade scopes? 6” f/8 reflectors. In the 1950s, what was the “serious” amateur telescope sold by Edmund and Criterion? A 6” f/8 reflector. In the 1970s when Meade was founded, what was their most popular product? A 6” f/8 reflector.
When the Dobsonian revolution began, what did early books like Build Your Own Telescope recommend making first? A 6” f/8 reflector.
The reason the 6” f/8 has been so ubiquitous, and is perhaps the perfect beginner’s telescope, is because it works. A 6” f/8 parabolic primary mirror is very easy to make, and the tube of a 6” f/8 is only 48” long, making it fairly portable and keeping the eyepiece at a comfortable height.
Lastly, at f/8 there’s no need to worry about ultra-precise collimation or the aberrations caused by using inexpensive eyepieces.
The focuser on both Orion SkyQuest XT6 variants is an all-plastic 1.25” rack-and-pinion. While functional, the focuser is easily damaged and Orion doesn’t sell a drop-in replacement – nor do any aftermarket vendors. This and the red dot finder are my biggest gripes with the XT6.
About the Accessories
The base XT6 comes with a single eyepiece – a 25mm Plossl(48x magnification). While nice, you do need a high power eyepiece or two. The XT6 Plus adds a 10mm Plossl(120x magnification) and 2x Barlow to the mix, making for a decent starter set.
The included red dot finder works adequately but a 9×50 finderscope or Telrad is a vastly better choice if you plan on much deep-sky observing. However, either is going to cost you some money that could also go towards another eyepiece.
Lastly, the Plus version adds a solar filter – rather pointless considering the current ultra-low state of solar activity but nice nonetheless.
How Good Is The Mount?
The regular Orion SkyQuest XT6 uses springs for tensioning, a system that in theory allows for easy balancing with heavy eyepieces, but without a 2” focuser you probably won’t be using very heavy eyepieces in the first place. It works just fine. The Plus version replaces the spring tensioning with a more conventional friction-based system, which is either an improvement or a downgrade depending on who you ask.
The XT6’s base is particle board overlaid with melamine. Not only is it heavy, but if the melamine is damaged the whole thing will quickly warp and rot. Thankfully, you can easily make your own base out of ¾” plywood or buy one from a third party should this ever become an issue. The Plus version slightly decreases the weight with cutouts but long-term the best solution is really just a new base. However, provided you take care of it and don’t mind the weight the stock base is just fine, and conveniently assembles out of the box in just a couple minutes with the included Allen key and screws.
What Can You See?
Even from the suburbs, a 6” telescope can be an absolute powerhouse.
Neptune’s moon Triton can be spotted, Saturn’s bands, Cassini division and several moons are easy, and Jupiter’s moons become disks rather than pinpoints. The smallest craters on the Moon visible are around a mile in size. Mars at opposition shows several dark markings and its ice cap.
The Orion Nebula begins to show a slight greenish coloring with a 6”, and globular clusters are somewhat resolvable. Many planetary nebulae, some showing a slight greenish or bluish tint, can be spotted. Under dark skies, M51’s spiral arms can be seen, along with several hundred other galaxies – a few dozen of which display considerable structure.
The Orion XT6 is again overall a great scope for beginners and for most users, I would probably recommend it over the gizmo-encrusted and more complicated beginner instruments like the Celestron AstroFi 130.
Overall the Orion SkyQuest XT6 is a remarkably simple instrument and probably one of the least complicated nor stressful telescopes to own – there’s no polar alignment to worry about, nor batteries or cables, nor GoTo calibration or precise collimation, nor dew, nor the quality of your eyepieces, nor the fear of getting a hernia from lifting a massive tube or base. Just plop the scope on the base, strap on the springs, tweak the collimation and you’re ready to go. It doesn’t matter how old you are or how much you know – you can use an XT6.