Orion replaces their popular 4.5-inch AstroBlast beginner telescope with the SkyScanner BL102. Is it a worthy successor?
For many years, I and many others have recommended Orion’s StarBlast reflectors on their sturdy Dobsonian mounts as great choices for anyone looking for the best value in a beginner telescope. I reviewed the 6-inch tabletop StarBlast here for AstroGearToday.
Alas, that telescope, and the 4.5-inch full-height StarBlast Dob, are victims of Orion’s purchase of Meade Instruments and the subsequent re-alignment of their product lines.
In their place, Orion now offers two “SkyScanner” branded telescopes, a 135mm (5.3-inch) f/8 full-height Dobsonian for $380, and the smaller tabletop 102mm (4-inch) f/6.3 reflector for $190 (on sale for $180 at the time of writing). The 102mm SkyScanner hits the price spot for many beginners, particularly parents seeking a starter scope for a child keen on seeing stars and planets.
To test how well it would meet expectations for a starter scope for under $200, I purchased a SkyScanner BL102 direct from Orion. Despite being shipped to me in Canada over the holiday weekends in early July, the telescope arrived by UPS only a week after ordering.
As with most Dobsonian mounts, some assembly is required, enough in the case of the SkyScanner that adult assistance will certainly be needed. The tube comes as a pre-assembled unit (with the exception of having to attach the little red-dot finder), but the mount’s wood parts require screwing together, in IKEA fashion.
The instruction manual (which covers both SkyScanner models) is fairly clear and all the screws and tools are supplied. I say “fairly clear” as it was not obvious what side of the vertical sideboard should face in or out. While assembly was quick and painless, I couldn’t help but think some background information (or a link to a video showing this model) explaining how Dobsonian mounts work would help even an adult using such a telescope for the first time.
The SkyScanner BL102 is compact enough that it can remain assembled and be carried outside in one piece. It should be manageable by an older child, though care has to be taken not to bang the plastic fittings that could break.
However, for proper use the telescope must be placed on a solid table or box. While the telescope itself is very sturdy, images will bounce around if the scope is on a shaky platform.
The key requirements for good performance mechanically in a beginner scope are simplicity of operation, with smooth, intuitive motions, and a lack of image-blurring vibrations. A wooden Dobsonian-style mount can deliver on all those counts.
The SkyScanner uses a single-arm design common to other small tabletop “Dobs.” It works very well, with the proviso that the two tension knobs, one on each axis, have to be adjusted just right to assure smooth motion for finding objects; not so loose that the scope moves inadvertently, or so tight that it’s hard to nudge the scope to follow targets.
The base of the mount turns on three ball-bearing rollers, not on pads of Teflon, as is usual with Dobs. This is an odd choice that can lead to motion in azimuth (left-right) that is much too loose — think of a spinning “Lazy Susan” turntable.
But the azimuth has a spring-loaded tension knob that can produce a good compromise of easy motion for making fine position adjustments without running away from the user. Nevertheless, a child will have some difficulty getting the scope set right for ease of use. I know I did. The similar up-down altitude tension is easier to adjust. The tube balanced fine with lightweight eyepieces, like the ones supplied and other Plössl eyepieces I tried.
The fittings — the focuser, finder, secondary mirror holder, and even the eyepieces — are all plastic. I suppose that’s to be expected today, and they all did work fine. The focuser is a rack-and-pinion design that worked well and was a definite improvement over the plastic helical (twist-type) focusers used on some competing tabletop Dobs.
The red-dot finder is decent, with adjustments in the X and Y axes to align it with the main optics and a useful two-level brightness switch. The finder’s plastic stalk strikes me as the most fragile part, prone to snapping off with an accidental bump. Its base is not the standard design used by larger finderscopes, and I didn’t see that the finder included with the SkyScanners could be purchased as a separate item from Orion should it need to be replaced.
So be careful! The lack of a working and properly aligned finder makes it tough to use any telescope, as beginners often find out.
The low power (26x) 25mm eyepiece is labeled as a Kellner design, while the higher power (64x) 10mm is called a Super Plössl. The 25mm Kellner presented a wider apparent field, at about 50°, than most bargain Kellner eyepieces. The 10mm was only a bit narrower with about a 45° apparent field. Thus, the views through both were not as “tunnel vision” as with many beginner-scope eyepieces.
In fact, images were quite sharp and pleasing in both eyepieces, not only at their centers but also across the fields. It would take a fairly costly upgrade to a set of top-quality Plössls or wide-field eyepieces to provide a significant improvement in the views. And any such eyepiece upgrade might cost as much as the telescope!
The SkyScanner comes with a 3x Barlow lens, again of plastic construction. But optically, the image quality was surprisingly good, lacking the colorful aberrations of most cheap Barlows.
It worked well with the 25mm eyepiece, tripling its power to 77x, helpful for better views of the planets, and nicely framing the entire Moon. But used with the 10mm eyepiece, the Barlow yields 192x, way too much power for this telescope. The image became too dim and fuzzy, and the target too hard to follow. An included 2x Barlow would have been a much better choice with this scope, and that might be a good accessory to buy later.
The optics arrived in excellent collimation, so no adjustments were necessary, though both mirrors have screws to allow for collimation if needed, and the manual provides instructions.
So, what about the quality of the main 4-inch mirror? It is f/6.3, so not as fast as some tabletop scopes, which is good as the primary mirror is listed as having a spherical, not parabolic, surface.
Spherical mirrors are easier and cheaper to manufacture, but can lead to the infamous defect that plagued the Hubble Space Telescope no less, spherical aberration, where all the light from across the mirror does not focus to the same point. The result is images that never snap into sharp focus. The aberration is mitigated by having a mirror made with a slower f-ratio, like f/6.3, or in the case of the larger 135mm SkyScanner, an f-ratio of f/8.
I was pleased to see that the SkyScanner 102 did not suffer from noticeable spherical aberration. However, at high power images did exhibit some astigmatism — star images looked elliptical, and planets never snapped into best focus.
So, the telescope did suffer from soft images at high power, but not for the reason I had expected. The cause did not seem to be mechanically pinched optics which, if that were the case, could be alleviated by loosening the adjustments that hold the mirrors. I tried, to no avail.
I suspect the culprit was a mirror, either the primary or the small secondary, ground with a misshapen curvature. This was the one flaws that spoiled an otherwise fine beginner scope, though it might have been unique to my test unit.
That said, the scope did provide good views of Jupiter’s cloud belts and Saturn’s rings, just not detail in the belts or rings.
Despite its one nagging optical flaw, the SkyScanner BL102 will certainly wow any new user with views of the Moon, and of lots of deep sky wonders at low power. The 4-inch aperture will provide much better views than any comparably priced 60mm refractor from a local big-box store.
For a budget of under $200, the SkyScanner BL102 is one of the best choices for a decent beginner telescope in today’s fast-changing market. If you can swing a higher budget, I suspect (but have not tested it to confirm) that the BL135 might be the better choice, where its longer focal length is likely to lend itself to sharper optics, yet still be child-friendly in size, and parent-friendly for cost.
While Orion offers 4.5-inch reflectors with parabolic mirrors in the $200 price range, the style of equatorial mounts they come with, while looking impressive and scientific, can be shaky, complex, and difficult to aim. I recommend beginners stay with simplicity, solidness, and ease of use. Orion’s SkyScanner BL102 provides all those traits at an attractive price.
Solid, easy-to-use mount
Decent fittings and accessories
Good aperture for the price
Slightly astigmatic optics in test sample
Motions require careful tension adjustments
Overpowered Barlow lens
MSRP: $189.99 plus shipping