The Optical Tube
The SkyProdigy 6 uses Celestron’s standard C6 optical tube, which was introduced in 2006. A 6” f/10 Schmidt-Cassegrain, the C6 is a great performer and fits into a very compact package. The C6 is compatible with Starizona’s HyperStar technology to turn it into an ultra-fast f/2 Schmidt camera (though you’d need a proper equatorial mount and, of course, a CCD or CMOS camera to attach to it). It will also work with a 2” diagonal or, for both visual and photographic use, Celestron’s f/6.3 reducer, and a variety of adapters can also be attached to the back thanks to the scope’s standardized rear threads.
Thanks to its small size, the C6’s manufacturing tolerances are a lot less stringent than a larger Schmidt-Cassegrain and as a result, the optics tend to be top-notch.
Like all Schmidt-Cassegrain telescopes sold by Celestron and Meade, the C6 focuses by moving the primary mirror along a threaded rod. This can sometimes result in an issue known as “image shift,” where the image tends to jiggle when focusing at high magnifications as the mirror flops on the rod. Thankfully, the C6’s small primary mirror also doesn’t weigh much, so image shift tends to not be a huge issue if it shows up much at all in the telescope.
For a telescope that retails for nearly a thousand dollars, the SkyProdigy’s accessories are a little lacking. It comes with the usual 1.25” visual back and diagonal, which is to be expected, but the eyepieces are Kellners (25mm and 10mm, providing 60x and 150x, respectively). Kellners aren’t bad eyepieces per se, but some proper Plossls or wide-angle eyepieces would be much appreciated given the scope’s high price tag.
The SkyProdigy 6 also comes with Celestron’s standard StarPointer red dot sight. If the SkyProdigy mount were to do its job correctly, you would never actually need this finder for anything, as the mount is, of course, supposed to align itself. Unfortunately, that is not usually the case.
The Celestron SkyProdigy Mount & StarSense Technology
The SkyProdigy mount is, more or less, a Celestron SLT mount with StarSense technology, a hand controller, and a camera integrated into it. While the SLT/SkyProdigy mount is admittedly not the most accurate thing available and the gears are on the cheap side, the build quality is overall decent enough to do the job – though of course, being a cheap alt-azimuth mount, it is utterly useless for long-exposure photography. Like the SLT, the SkyProdigy mount uses rather spindly 1.25” steel tripod legs, and as a result, it’s not as stable with the C6 OTA as one would probably like (though it does work okay, especially if you don’t extend the legs all the way and fill them with foam or sand). The C6 attaches to it via a standard Vixen-style dovetail plate connection.
The biggest difference from the SLT mount that the SkyProdigy, of course, possesses is the StarSense camera and software. The StarSense basically works by taking at least a dozen pictures of random portions of the sky and determining their positions via a built-in star map—a process known as plate solving. Plate-solving is used by many astrophotographers to skip the time-consuming process of aligning an equatorial mount’s GoTo system after it has been polar aligned and to verify that a dim target that may not show up in a short exposure is indeed in the frame. However, this version of plate solving is usually only used on an equatorial mount and involves simply slewing to where the target is supposed to be, taking a snapshot, and making corrections until it is centered—not taking pictures of the whole sky. And with an equatorial mount and good polar alignment, the mount/scope already knows where north, south, east, and west are – something the SkyProdigy’s alt-azimuth mount cannot do.
Unfortunately, as a result of how it works, the StarSense technology needs a lot of things to go perfectly right to function correctly, including a well-leveled tripod, no large obstructions in the sky by trees or buildings, and for the camera to be properly aligned to the telescope tube. This last one, unfortunately, is basically impossible for the SkyProdigy to achieve. Celestron sells the StarSense tech as an add-on for your existing mount, and in that configuration, the camera is piggybacked atop the telescope tube and can be calibrated to sync up with the telescope in case there is any mechanical misalignment. However, the SkyProdigy’s StarSense camera is built into the mount, has no sync procedure that you can do yourself, and, of course, the alignment will probably change slightly every time you remove the tube from the mount and attach it again. Additionally, the wobbly stock tripod on the scope means that all sorts of additional inaccuracies are almost guaranteed to show up.
As a result of its design, even if you are able to achieve satisfactory conditions and stabilize the tripod, the likelihood of the SkyProdigy being able to align itself at all is not very high, and even if it is “successful,” you may be faced with an extremely inaccurate alignment and the telescope pointing several degrees away from where it should be – and this is why Celestron has so helpfully given the scope a red dot sight. Provided you know the names of some stars and how to align the finder (y’know, only the two things the SkyProdigy is supposed to obviate the need for) you can sync the telescope and be on your merry way – and have completely eliminated the point of the StarSense tech and spent hundreds of dollars more than you could have a NexStar SLT or NexStar 6SE, either of which will deliver the same result (and the latter with a more stable mount to boot).
Should I buy a Used SkyProdigy 6?
Unless it’s so cheap that you’re getting the mount for free and are willing to buy something else for the C6 optical tube to ride on, no.
What can you see with Celestron Skyprodigy 6 SCT?
Provided you can get it to work, the SkyProdigy 6 will excel at views of the moon and planets. You’ll have no trouble seeing Jupiter’s cloud belts, the Great Red Spot, and its 4 brightest moons. Saturn’s rings, the Cassini Division in them, its cloud belts, and around half a dozen moons are no problem. Mars’ darker regions and ice cap are visible when the planet is at and near opposition, and you can, of course, see the phases of Venus and Mercury. Uranus and Neptune are small bluish dots, and you may be able to pick out Neptune’s moon Triton with good skies and some effort. The Moon will also show a large amount of detail, with features as small as about 2 miles (3 kilometers) visible.
Beside the Moon and planets, there are hundreds of open star clusters that the SkyProdigy 6 can show you, along with several dozen globular clusters that will appear as grainy fuzzballs. There are also a handful of bright emission nebulae such as the Orion, Lagoon, and Swan Nebulae that will look absolutely fantastic, especially under dark skies, a couple dozen planetary nebulae (most of which will appear as tiny, albeit perhaps colorful, fuzzy dots), and, of course, a great number of galaxies, though keep in mind that few will have much in the way of visible detail.