315+ Telescopes Ranked

View Rankings
Having collaborated with astronomy retailers and as an Amazon Associate, we earn from qualifying purchases. See full disclosure.

Orion StarBlast 4.5 Astro Reflector Reviewed – Editor’s Choice

The Orion StarBlast 4.5 Astro is an excellent beginner scope or “grab n’ go” complement to a larger instrument, and is sold at a remarkably low price.
Photo of author

When you read one of my reviews at TelescopicWatch, you can trust that not only have I gotten to use the product, but I’ve compared it to numerous others and tinkered with it down to the literal nuts and bolts. When I'm not writing reviews, I'm out under the night sky with my own homemade or modified telescopes, with over 7 years of hands-on experience in astronomy, having owned 430 telescopes myself, of which 20 I built entirely.

Tested by

Score Breakdown

Optics: 4/5

Focuser: 3/5

Mount: 4/5

Moon & Planets: 3/5

Rich Field: 5/5

Accessories: 3/5

Ease of use: 5/5

Portability: 5/5

Value: 5/5

Read our scoring methodology here

The Orion StarBlast 4.5 Astro is a small but capable telescope ideal for beginners or experienced astronomers alike, with a 4.5” primary mirror offering sharp wide-field vistas of deep-sky objects thanks to its mere 450mm focal length as well as great high-resolution views of the moon, planets and double stars. The StarBlast 4.5 Astro continues to shine as one of the best telescopes available after nearly two decades of availability, essentially unchanged apart from a few accessory swaps and upgrades.

Orion StarBlast 4.5 Astro

How It Stacks Up







Orion StarBlast 4.5 Astro


See All Telescopes' Ranklist

Best Similar Featured Alternative: Orion StarBlast 4.5 Astro is indeed the best 4.5" dobsonian.

What We Like

What We Don't Like

  • A 130mm or 150mm scope is a lot more capable for only a little more money
  • Needs very short focal length eyepieces and/or Barlow lens for high magnifications
  • Can be hard to find a sturdy surface to set the scope on
  • No dovetail for attaching tube to other mounts
TelescopicWatch Editor's Choice

The Orion StarBlast 4.5 Astro is an ideal telescope for the price. It’s got enough aperture to actually show you things and the scope excels at both high-power and wide-field viewing. The tabletop Dobsonian mount is easy to use, and the included accessories are good enough to get you started.

Buy from Recommended Retailer

For smaller telescopes and accessories, ordering off Amazon tends to be the most seamless and often cheap option, even when compared to our favorite astronomy retailers.

Optical Performance Of Starblast 4.5

The Orion StarBlast 4.5 Astro is a 4.5ʺ f/4 Newtonian with a focal length of 450mm. Originally designed to compete with the sadly-discontinued Edmund Astroscan, the StarBlast 4.5 excels as a wide-field telescope, offering a nearly 4° field of view (that’s eight full moons across!), along with a 32 mm Plossl or 24 mm wide-field eyepiece (not included). Both the optical tube and mount of this scope are identical to the Zhumell Z114, which we also recommend.

Orion Starblast 4.5 Astro at floor
Pic by Zane Landers

While primarily a wide-field instrument, the StarBlast performs pretty well on the Moon and planets, much better than the 60-90mm refractors often cited as good beginner scopes. And of course, it’s no contest when it comes to deep-sky objects. It does need collimating, but that’s an easy task. The focuser is a standard 1.25” rack-and-pinion unit.

The StarBlast attaches to its mount with a simple clamping tube ring, allowing you to slide the tube back and forth and rotate it. For mounting it on a full-sized equatorial or alt-azimuth mount, you’ll need a pair of tube rings and a dovetail plate.


The StarBlast 4.5 Astro includes two eyepieces: 20mm (23x) and 10mm (45x) oculars, seemingly of some variant of the Kellner or Plossl design. They work well, though you really need a short focal length eyepiece of 6mm or below to get reasonably good planetary views out of the StarBlast’s short 450 mm focal length, and a wide-angle eyepiece in the 25mm range will give you a wider and slightly sharper view than the stock 20mm does.

As with most beginner scopes, the StarBlast 4.5 Astro is provided with a red dot finder for aiming—more than adequate given its ultra-wide field of view. A 13% transmission “Moon filter” is also included; this silly piece of glass does nothing but slightly blur and pointlessly dim your view of the Moon, which, while dazzling, cannot actually harm your eyes, even in a very large telescope.

Reviewing Mount Features

The StarBlast 4.5 Astro was a pioneering scope for introducing the tabletop Dobsonian mount to the world. While not a true “Dobsonian” due to the single-sided bearing, which doesn’t use any Teflon pads, the tabletop mount of the StarBlast is lightweight, compact, easy to aim, and extremely cheap to construct. 

Orion 10015 StarBlast 4.5 Astro Reflector Telescope

Orion Starblast 4.5 Astro’s mount has a wider footprint than some competing models, which makes it more steady and less prone to being knocked over.

We earn a commission if you click this link and make a purchase at no additional cost to you

Starblast 4.5 astro Orion

However, you’ll need a milk crate and a chair to comfortably use it. A Rubbermaid bin or similar will also work as a stand, but it will hamper the scope’s portability. Sticking the scope on top of a bar stool or car hood also works in a pinch, or you could make a custom stand/tripod for it pretty cheaply.

Alternative Recommendations

Besides the Zhumell Z114, which is essentially the same telescope apart from including slightly different eyepieces, there are a few other scopes you might want to consider in lieu of the Orion StarBlast 4.5 Astro if you’re on a tight budget or looking to get a larger instrument.

  • The Sky-Watcher Heritage 150P offers considerably more light gathering and resolving power than the StarBlast 4.5 Astro and is easier to collimate at its f/5 focal ratio, while the collapsible tube helps minimize volume when the scope is not in use.
  • The Sky-Watcher Heritage 130P features a bit more light gathering and resolution ability compared to the StarBlast 4.5 Astro while also being easier to collimate at f/5, and just as compact as the StarBlast thanks to its collapsible tube.

Aftermarket Accessory Recommendations

A 6mm “gold-line” or “red-line” eyepiece (75x) would be ideal for augmenting your eyepiece collection for the StarBlast 4.5 Astro at the high-power end, and a 2x Barlow lens will allow you to double the power to 150x, which is about the limit of what the StarBlast can handle. 

For low power, a 25mm Plossl provides 18x and a 3-degree field of view. A 25mm Agena Starguider, while expensive, will deliver sharper stars at the edges and extend the field out to about 3.3 degrees.

You could add in additional eyepieces in the 9–15 mm range to further extend your magnification options, but a good high-power eyepiece and a good 24-26mm eyepiece for the maximum possible field of view is all you probably need with the StarBlast.

Lastly, one other accessory you might want to pick up is Orion’s UltraBlock UHC filter. It doesn’t “filter out” light pollution but rather increases contrast on nebulae, making them appear brighter against the background and bringing out subtle detail. This filter works great with the StarBlast, which will show you huge swaths of sky containing regions like the North America, Veil, Lagoon, Trifid, Swan, and Eagle Nebula. Even under a dark sky, the UHC brings out more contrast by darkening the sky background.

What can you see?

The StarBlast is optimized for wide fields. It’s primarily made for low-power viewing of nebulae and star clusters. That being said, it’s a pretty good lunar and planetary instrument too.

Even from the suburbs, the Veil Nebula is fantastic with an oxygen-III or UHC filter. The Milky Way is very fun to explore, in both summer and winter. Open clusters are a joy with this telescope. Under dark skies, the many dark nebulae that cross the summer Milky Way are great, challenging objects to hunt for with the StarBlast. The Andromeda Galaxy’s dust lane is an easy catch with a wide-field scope like the StarBlast, though few other galaxies will present any meaningful detail due to the StarBlast’s small aperture. Bright emission nebulae like Orion, the Lagoon, and the Swan look magnificent, especially from dark skies or with a UHC filter.

At high magnification, Jupiter’s Great Red Spot and cloud belts are no problem. You may just be able to spot Jupiter’s moons and their shadows crossing the planet.

Saturn’s Cassini Division is easy to spot on a night of good seeing, as are a few of its brightest moons. Venus’ phases are easy, and Mars will show a few dark regions and the ice cap when it’s at or near opposition. Uranus and Neptune, if you can find them, are little more than star-like bluish dots with the StarBlast.

Optical Design:Newtonian Reflector
Mount Design:Alt-Azimuth
Focal Length:450mm
Focal Ratio:f/4
Focuser:1.25" Rack-and-pinion
Fully Assembled Weight:13 lbs
Warranty:1 year limited

Zane Landers

An amateur astronomer and telescope maker from Connecticut who has been featured on TIME magazineNational GeographicLa Vanguardia, and Clarin, The Guardian, The Arizona Daily Star, and Astronomy Technology Today and had won the Stellafane 1st and 3rd place Junior Awards in the 2018 Convention. Zane has owned over 425 telescopes, of which around 400 he has actually gotten to take out under the stars. These range from the stuff we review on TelescopicWatch to homemade or antique telescopes; the oldest he has owned or worked on so far was an Emil Busch refractor made shortly before the outbreak of World War I. Many of these are telescopes that he repaired or built.

3 thoughts on “Orion StarBlast 4.5 Astro Reflector Reviewed – Editor’s Choice”

  1. The eyepieces aren’t plossls. I’ve seen several mentions of both being plossls, and I did take the 17mm apart to confirm it. There are definitely 2 doublets in 2 groups. I guess they could be some other similar design, but they definitely aren’t Kellners, MA, SMA or RKE.


Leave a Comment