Celestron AstroMaster 90 EQ Refractor Telescope Review


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Price is a major factor to consider when you’re in the market for a refractor telescope.

If you don’t want to settle for a 70 or even 80 mm refractor, then consider the AstroMaster 90 EQ telescope with its 90 mm aperture that doesn’t break the bank.

It’s a great size for a beginner and obviously has increased light grasp than a smaller model.

With an EQ mount, you can also manually track objects, so you can keep that target within your field of view.

It may not be as easy for beginners to master EQ movement, but you’ve got to start somewhere if you want to one day learn how to track and take snapshots of the sky.

However, with the low price comes compromise.

It’s not a do-all, see-all kind of telescope, and it certainly is not your astrophotography champ.

Here’s the good and the bad.

Zooming in…

✔️ Best Feature: Good optics

Worst Feature: Mount and tripod

👌 Ideal For: Celestial Viewing, Terrestrial Viewing, Lunar & Planetary Observation, Bright DSO Viewing, Limited Astrophotography, Kids, Beginners

  • Optical Design: Refractor
  • Aperture: 90 mm
  • Focal Length: 1000 mm
  • Focal Ratio: f/11
  • Eyepieces Included: 20 mm, 10 mm

Our Verdict: Refractors are one of the most revered optical designs in the telescope industry, but they’re a lot more expensive than other designs. The same can be said about EQ mounts. Well, the AstroMaster 90EQ combines a refractor telescope with a manual EQ mount in an inexpensive package ready for lunar and planetary observation for amateur and aspiring astronomers.

Who is the Celestron AstroMaster 90EQ Best Suited to?

The AstroMaster 90EQ is an entry-level telescope designed for beginners. It checks a few things off the list for a beginner looking for specific features. These include refractor design, EQ mount, and included accessories.

Even though this excellent telescope under $300 is mainly marketed towards adults, it would easily suffice as a family telescope for viewing the moon, planets, and even land-based objects. An erect image diagonal is included to provide terrestrial viewing.

Intermediate and expert users will find flaws with the AstroMaster but none that can’t be resolved or worked around. As an entry-level, lightweight, and affordable refractor, beginner users will find value and will acquire new skills with this telescope.

How Does the Celestron AstroMaster 90EQ Perform?

The AstroMaster 90EQ provides great seeing for a cheap refractor. Its slow focal specs and small aperture show that its strong suit is within our solar system for great views of individual features on the moon and planets. Its aperture is on the small side at 3.5”, but as a refractor, it promises strong resolution and crisp images with some compromise on color fidelity.

You can see Saturn with some of its moons. Jupiter and its moons and cloud bands. DSOs may be difficult to achieve as the AstroMaster just doesn’t have the aperture to gather enough light to resolve details. You will be able to see the brightest DSOs and possibly capture images of small planetary nebulae.

Of course, acquiring better seeing will be easier to do when you have quality eyepieces, perhaps a Barlow lens, and can observe from a dark location with minimal atmospheric and light pollution.

When it comes to build quality, it passes the bar. It has a steady and price-appropriate mount, but you will want an upgrade down the road.

Features & Benefits

Good OTA

The 90EQ is one of the refractors in the AstroMaster series. As a refractor, it has closed optics, collimation is rarely needed (if at all), and it has good contrast. With a slow focal ratio of f/11, it will make a great lunar and planetary telescope for beginners on a budget looking for a refractor. The scope has multi-coated optics and the larger aperture allows for more light grasp than its smaller refractor alternatives.

One downside is the fact that the dovetail is extremely short. This makes it difficult for balancing the very long tube, but Celestron includes counterweights to help with balance. You’ll only need one counterweight for most purposes, but if you add extra weight like with a heavy eyepiece or camera, you’ll need the other counterweight.

Additionally, the dovetail is attached directly to the tube, so there is no possible way to rotate the tube for easier viewing positions especially when looking through the viewfinder.

Accessories

There aren’t a whole lot of accessories included in the buy, but what is included works appropriately with this setup. The 20 mm and 10 mm eyepieces provide 50x and 100x magnification respectively. The 20 mm will be your low-power, wide-field eyepiece and the 10 mm Kellner will be your high-power eyepiece. Seeing quality is good for the price and is as expected in this buy even if the diagonal dims the seeing somewhat.

Having just mentioned the diagonal, yes, a 90-degree erect image diagonal is included with the AstroMaster telescope. Its angled design is ideal for astronomical use, but it also provides correct orientation for terrestrial viewing. This is a convenient feature for beginner users who may want to use the telescope as a spotting scope.

A StarPointer finderscope is a red dot sighting tool with a much wider field of view than what you can see through the eyepiece. You use it to find objects, but it may get awkward to use when viewing near zenith as you will be forced to move super low.

EQ Mount

The 90EQ model has a CG-3 equatorial mount. It provides manual EQ movement for tracking an object in the sky to counteract for field rotation. To make minute adjustments, both the RA and Dec axes have slow motion controls. The tripod is steady and durable with its three legs, tightening knobs, and center bracket. To reduce any shaking you may experience, make sure the tripod is on a solid and level surface.

Limited Astrophotography

The AstroMaster is not going to be your starter astrophotography telescope, but you can take amateur shots of the moon and planets with a smartphone and adapter. You could use a webcam-style CCD camera for planetary imaging.

Even though the scope has an EQ mount for manual tracking of a sky target, you’ll need a clock drive for motorized tracking. The 90EQ is compatible with motor drives but the entire setup will only be good for capturing photos of the moon and planets.

What about a DSLR camera? You will need to upgrade the mount to a finely-geared and heavy-duty one to prevent strain and inaccuracies from the weight of additional astrophotography gear. Additionally, with its slow-ish focal ratio, it will take longer to capture images.

Limitations

Mount & Tripod

The unfortunate part of the tripod is its plastic parts. They can break easily even if you’re not rough with it. Additionally, most of the wobbling can occur when you have the tripod legs fully extended, and with such a long tube, you may very well need that height from the tripod if you’re an adult and like to stand while observing. Additionally, because the CG-3 mount is a light-duty mount, making various adjustments to the telescope may cause the setup to wobble.

The slow-motion controls have said to be quite rough to adjust. Admittedly, they’re not as smooth or accurate as they could be. A little silicon grease could help with this. It’s not the most trustworthy tripod available but considering that better mounts cost more than the entire AstroMaster telescope itself, it suffices as a recreational mounting system for amateur use on a budget.

Popular Questions

Is the Finder Scope Removable on the AstroMaster Telescope?

The AstroMaster 90EQ comes with the StarPointer red dot finder scope. It is not permanently mounted to the tube. It mounts to the tube via a dovetail bracket and two screws that keep the finder in place. You will be expected to mount the finder to the tube. You can replace it if you desire a different one.

Is the Image Upside Down Through the AstroMaster 90EQ?

No. The AstroMaster 90EQ comes with a 90-degree erect image diagonal that provides correctly orientated images when viewing through the eyepiece. This makes it a suitable alternative spotting scope for observing land-based targets or birdwatching. In the sky, image orientation is inconsequential.

Is the Celestron AstroMaster Good for Deep Sky Observation?

Unfortunately, the 90EQ model is a not a good deep sky telescope. It has a small aperture that limits the amount of light grasp needed to see faint DSOs (Deep Sky Objects). If you are interested in seeing deep space bodies with no astrophotography benefits, a large aperture Newtonian reflector on a Dobsonian-style mount may be the best way to go for the money. The AstroMaster 90EQ is good for seeing only the brightest DSOs such as the Pleiades, Orion Nebula, and the like. It performs better for lunar and planetary observation.

Is the Celestron Telescope Portable?

The AstroMaster 90EQ is a portable scope, well, as portable as can be for a telescope. The tube length is 36” and the total assembly weight is 27 lbs with the mount and tripod. Even though it’s less than 30 lbs, the long tube can make it awkward to transport. It’s best to detach the tube from the mount/tripod assembly and haul it in two pieces.

Conclusion

The AstroMaster 90EQ from Celestron is a decent entry-level telescope that allows you to own a refractor with EQ movement while sticking to a budget.

It has many good features and benefits but is not without flaws.

If you’re expecting deep sky viewing and the possibility of having maximum astrophotography benefits, you’ll be sorely disappointed and it’s obviously not for you.

If you’re after an affordable refractor that’s good for occasional viewing with the family for both terrestrial and celestial use, good seeing for the moon, eclipses, and the planets, you may be well-matched with he AstroMaster.

With good care, some know-how about telescopes, and possibly some better accessories, the AstroMaster will perform better than expected.

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