orion skyscanner 100mm

The Orion SkyScanner 100mm TableTop Review: A Quality Starter for Amateur Astronomers

  • Overview
  • in depth Review of Features
  • comparisons



The Orion SkyScanner 100mm is an reflector telescope. While Orion has positioned the SkyScanner as a beginner telescope in its marketing materials, it offers a great deal more in the way of value and quality than a lot of the lower-level beginner telescopes on the market. For one, its larger aperture offers greater brightness and clarity. It also eschews less expensive plastic optics in favor of higher-quality materials to improve the user experience and image quality.

Reflector telescopes are those that use a mirror or series of mirrors to gather light and convey images to the eye of the viewer. Lower-end telescopes tend to favor refraction over reflection because, all things being equal, it tends to be cheaper to manufacture lenses than it is to manufacture mirrors of similar quality. That the SkyScanner is a reflector at this price point makes it relatively rare among telescopes for beginners.​

The benefit of a reflector, as we've discussed before, is that ​perfection is easier to achieve with mirror than it is with a lens. With a lens, light must pass through the entirety of the material before it passes on to the eye of the viewer. The result of this is that tiny imperfections anywhere in the substance of the lens can affect the quality of the image. To make a perfect lens, you must make the entire thing perfect.

Mirrors, on the other hand, merely reflect the light via their surface. The result of this is that tiny imperfections below the surface of a mirror have no affect on image quality. ​As long as those imperfections aren't on the surface of the mirror, image quality will be preserved.

Another benefit of reflector telescopes is that mirrors don't suffer from ​the chromatic aberration that lenses do. Chromatic aberration occurs when the different wavelengths comprising light pass through a lens at different rates because of the particular material used to construct the lens. The result of these different rates is a distortion that must be corrected after the fact in order to preserve a true image. Reflector telescopes also avoid this problem because the light does not have to pass through the material of the mirror. It need only interact with the surface of the mirror before it is passed on to the viewer.

That's not to say that the use of mirrors in reflecting telescopes doesn't have its own set of drawbacks. There are some challenges reflecting telescope users face that aren't a problem with reflector telescopes because of their use of lenses instead of mirrors.

The first problem with mirrors is that they tend to be more expensive to make. As we mentioned before, the fact that the SkyScanner can be purchased at this price in spite of its use of mirrors is remarkable.

Second, unlike lenses, which can be firmly held in place by their sides, mirrors tend not to be fixed within the tube of the telescope. The result of this is greater need for collimation (adjustment) than can reduce the usability and simplicity of a telescope.

Third, because telescopes like the SkyScanner often use parabolic mirrors, users sometimes report image clarity that is less crisp near the edges.​

Mirrors also can suffer from light reduction and loss of contrast because their images must be reflected off of a second mirror to convey the image to the eye of the viewer.

reflecting telescope diagram

Image: Diagram of a reflector telescope

The SkyScanner itself exhibits all of the benefits and detriments of its construction. Orion opted to use real, non-plastic optics here, which increases image quality and clarity. The 100mm aperture is great in relation to smaller apertures because it lets in a ton more light. This greatly increases image brightness, which means you can go beyond just viewing the Moon and planets to actually seeing the brighter deep-sky objects and Messier objects.

Given that we're actually just beyond that 60mm - 80mm diameter aperture range usually available to beginners, you can imagine what functions the SkyScanner is most effective at performing. It's certainly effective for viewing terrestrial objects and the planets. A lot of beginner scopes will give you access to those.

Another plus about the SkyScanner is that it's a true Newtonian reflector with a parabolic mirror. Unlike the Jones-Bird configuration that a lot of lower-priced telescopes choose in order to correct the image, the SkyScanner eschews an added lens.​

The SkyScanner 100 vs the 4.5-inch StarBlast

A lot of people are drawn to the SkyScanner because it has similar characteristics to the Orion StarBlast 4.5 Astro at a fraction of the price and weight.

[Check out our full review of the StarBlast 4.5 here.]

Its aperture is nearly as large as that of the StarBlast, which leads a lot of people to think that the SkyScanner is an equivalent of the StarBlast at a lower cost.

While these are not actually similar telescopes, that doesn't mean that the SkyScanner doesn't have a lot of merit, even in comparison to the StarBlast 4.5.

The first way in which the SkyScanner differs from the StarBlast  is that its mirror isn't diffraction limited. This of course can have an effect on image quality.

The way their respective mirrors are fixed also makes the StarBlast much easier to collimate than the SkyScanner. It also has a longer cool-down time than that of the StarBlast.

The SkyScanner also lacks one of the features that really sets the StarBlast apart, which is the ability to change the orientation of the tube in its rings. This feature makes the StarBlast really easy to use with a tabletop mount because you can always get the eyepiece in a position that's easy to use. But it's also fair to add here that this is a feature that's lacking in a lot of commercially-available telescopes, even ones that are significantly more expensive.

But the SkyScanner does compare favorably in a couple of ways. The first is that the SkyScanner comes threaded for attachment to a tripod. The StarBlast lacks this feature, which can really come in handy and makes the SkyScanner quite flexible and convenient. This can also be a factor to consider when you're looking for an astrophotography telescope. The StarBlast isn't threaded to allow attachment to photo tripods.

The second point of comparison where the SkyScanner wins is cost. In most cases, you can find the SkyScanner for about half the cost of the StarBlast, which is no small feat when you're on a tight budget.

Ultimately, the comparison is a bit of an unfair one in that these are very different scopes. The SkyScanner would likely pale in comparison to the StarBlast. We recommend comparing it, instead, to other entry-level telescopes in the 60-80mm range, a comparison in which the SkyScanner could come out way ahead.​

However, the SkyScanner additionally gives users a view of  brighter celestial phenomena like Orion, Andromeda, and the Messier objects. The ones you can see are more numerous than those on a telescope with a smaller aperture.

One thing to keep in mind about the SkyScanner is that it's best used for wide-field viewing. Because of its relatively shore focal ratio (f/4), some objects can become distorted near to the edge of the field of view, although it is still an impressive telescope at its price point.​

The thing to remember with the SkyScanner is that you get the most aperture possible for around $100, depending on which package you select. It also has a ton of flexibility because of its other accessories.

This is a fine telescope with some predictable limitations, but for the price it won't disappoint, and could pleasantly surprise you.​


The SkyScanner is mounted on a tabletop swivel alt-azimuth mount. It swivels up and down and left and right. Of course, under normal circumstances this will require a tabletop to stabilize the telescope.

The action of the mount is smooth enough and works well. This type of mount is favored by many beginners because it allows for fast setup and facilitates easy mobility. If you're just using this mount for basic viewing, it will work great in most cases.

The tabletop mount especially makes the SkyScanner an effective grab and go scope, as there is no need for putting up and taking down a tripod mount. It takes up very little space despite its good stability and pleasing image size and brightness. This is also a great scope for people who live in small spaces like apartments or dorms, or who live in the city. The SkyScanner just doesn't take up much room, and when you need to move it you can do so without any trouble.

However, not everybody is in love the with idea of using a table-mounted telescope. Tabletop mounts tend to limit viewing angle in some cases, and don't always offer a lot of space for viewing.

If you're one of those people who doesn't love tabletop mounts, the mount also comes with a threaded adapter for use on a standard tripod. This feature becomes particularly useful for those who are looking to use their telescope for astrophotography. Because the tabletop mount does a poor job of offsetting and accommodating the weight of cameras and astrophotography adapters, a decent tripod will probably become necessary.

One limiting factor in trying to change the mount is the SkyScanner's use of the Vixen DoveTail, which is attached directly to the end of the telescope. This can make for some awkward viewing when you use this with mounts that have dovetail saddles in different positions. Just keep in mind the position the eyepiece will be in depending on the mount configuration.​


The Orion SkyScanner comes with the standard EZ Finder II, a basic red-dot finder. The EZ Finder II works by projecting a red dot onto a window in the finder. As you view the target through the window, you move the scope until the red dot lines up with the target.

This works fairly well, and it's certainly better than a lot of the finder scopes on the market. We found the red dot to be a bit too bright; it might be more effective if it were a bit dimmer.

The SkyScanner standard package includes Orion's Starry Night Special Edition Software. This software allows you to educate yourself on what you might be seeing in the sky from the comfort of your own computer. You can also prep for viewing with your own star charts and maps. As we've said before about the Starry Night software, its inclusion isn't a reason to buy one telescope versus another, but it's a nice additional feature that can sweeten the deal.​