Orion SkyQuest XT4.5 Overview Research

Written by Astrosyo

The Orion SkyQuest XT4.5 is a quirky little Dobsonian with a design you won’t see in many other beginner scopes. Its unusually long tube houses a spherical mirror, a choice that Orion offset with clever engineering. The result? A telescope that delivers surprisingly sharp planetary views, though with compromises in ergonomics and wide-field deep-sky observing. Depending on what you’re looking for, this scope can either feel awkward or like a gem you’ll keep for years.

Optics

The XT4.5’s 114 mm spherical primary mirror is paired with a long 900 mm focal length — unusual for a telescope this small. Orion designed it this way to reduce spherical aberration, and it works: views are sharper than most beginner scopes at this price. The f/7.9 focal ratio makes it particularly friendly for high-magnification planetary observing, though it does narrow the field of view. Collimation is also simpler than with short-tube reflectors, a nice bonus for new observers.

Planetary & Lunar Performance

This is where the XT4.5 shines. Jupiter’s cloud bands, the Great Red Spot, and Galilean moons are visible. Saturn reveals its rings and Cassini Division, along with Titan. Mars shows polar caps and dark surface markings during favorable oppositions. The Moon is razor-sharp across its craters and maria. Venus’s phases are easy to see, and Uranus/Neptune appear as small colored disks. For planetary detail at this size, the XT4.5 performs better than expected.

Deep-Sky Performance

The narrow field of view is the biggest limitation. Bright objects like Orion Nebula, Andromeda Galaxy, and open clusters are viewable, but larger nebulae and extended galaxies don’t fit comfortably. Sharpness is good, but deep-sky performance feels restricted compared to wider-field 130 mm reflectors or 6″ Dobsonians.

Mount

The Dobsonian base is stable and smooth, handling the long tube without issue. Motions are easy to control, and the friction bearings allow for decent adjustment. It’s a simple, reliable design — exactly what a small Dobsonian should have.

Ergonomics

The 900 mm tube makes the eyepiece position awkward for adults. You’ll often need to hunch over or place the scope on a table or stand. For children, though, this height is perfect — making the XT4.5 a surprisingly good family telescope for younger observers. Just remember that a table or extra stand will become part of your regular observing kit.

Accessories

The included 25 mm (36x) and 10 mm (90x) Plössl eyepieces are a pleasant surprise — both are usable and provide good performance out of the box. Unfortunately, the 6x26 finder is underwhelming: the image is dim and small, making star-hopping difficult. Many users replace it with a red dot finder. The plastic focuser is basic, but smooth enough for casual observing and helps keep costs down.

Conclusion

The Orion SkyQuest XT4.5 is not a one-size-fits-all telescope. Its design favors planetary and lunar observers who value sharp, high-magnification views in a compact aperture. The long tube and awkward ergonomics may frustrate some adults, and the narrow field of view limits deep-sky exploration. But for kids, families, or anyone primarily interested in Solar System targets, the XT4.5 is a unique and well-built option that can serve faithfully for years.

Alternatives

If you want a more balanced all-rounder, a 6″ or 8″ Dobsonian is the next logical step. A 130 mm tabletop reflector is another alternative: wider field of view, easier ergonomics, but slightly less planetary detail compared to the XT4.5.