Disclosure - TelescopicWatch is reader supported. If you buy something via our link, we may earn a commission.

Celestron 21061 AstroMaster 70AZ Review

Celestron’s AstroMaster 70AZ promises to be a fully-functioning telescope for under 150 dollars in price – and a refractor on a tripod, at that. So does it deliver? 

Continue to read this Celestron 21061 Astromaster 70AZ refractor telescope review to find out. 

Basic Features

  • Aperture: 2.76 in. (70mm)
  • Focal length: 900mm
  • Focal ratio: 12.86
  • Mount: Manual Altazimuth
  • Focuser: 1.25″ Rack-and-Pinion

Overview

The AstroMaster 70 is a 70mm f/12 achromatic refractor, using a standard Fraunhofer configuration with crown and flint glasses for the objective lens. The long focal ratio means that there is little in the way of chromatic aberration (false color), although not the near-zero that a 60mm f/15 refractor or the like provides.

The scope has an ample length dew shield, which also serves as a light shield to boost contrast – though it isn’t really painted a good flat black on the inside.

The AstroMaster 70 has a 1.25” rack and pinion focuser which is mostly plastic. It works well. The red-dot finder is attached to the left side of the focuser and is more than adequate for a small scope such as a 70mm refractor.

My main complaint about the optical tube is that, like most of the AstroMaster scopes it seems, it can’t be balanced if you have anything remotely heavy on the focuser. The dovetail plate which attaches to the mount is too short to slide it for balancing and the scope has no tube rings – the dovetail is directly attached via some screws in the tube.

Reviewing The Attached Accessories

The AstroMaster 70 comes with a cheap, mostly plastic Amici diagonal designed to be used for terrestrial viewing. If you’re wondering about the odd shape of the diagonal and the strange grip that seems to be built in, it’s because Celestron has figured out that people tend to grab the diagonal and use it as a handle, and they designed it accordingly to be a little more suitable for that function.

The Amici prism produces a bright spike on bright stars and the planets and isn’t very high in quality. A proper diagonal would cost nearly half the price of the telescope, however, and Celestron does bill this scope for terrestrial viewing, so I’ll give it a pass.

The AstroMaster 70 comes with two surprisingly decent Kellner eyepieces – 20mm and 10mm, giving 45x and 90x magnification respectively. 45x is a little much for low power with a 70mm telescope, however – a 25mm or 32mm eyepiece would be better.

AstroMaster 70's Mount Capabilities

The AstroMaster 70’s mount is basically a glorified camera tripod, although not with a fluid head (thank goodness – it would be impossible to use if it were such a thing). There is a panhandle and there are simple locks/clutches for both the altitude and azimuth axes.

This would work fine with a short, fast 70mm telescope, but the configuration of this mount presents two problems with such a long refractor. For one, the scope will only be balanced at certain altitude angles – the rest of the time you have to tighten down the altitude lock. Ever wonder why more expensive alt-az mounted scopes have those weird angled sides? It’s to keep the center of mass of the tube at the center of torque of the mount. The AstroMaster 70’s mount doesn’t do this. The effect is exaggerated by the long tube, which provides a longer moment arm and thus a greater difference in torque depending on how high the scope is pointed.

Second, without slow-motion controls, you’ll struggle to keep objects centered or even in the field of view at all when tracking at high power. This isn’t helped by the fact that the tripod isn’t the most stable, as the legs are quite thin – though it works well enough, especially considering the price.

What All Can You See?

If you can get over the mount issues, the AstroMaster 70 will show you Mercury and Venus’ phases, a wealth of detail on the Moon, Jupiter’s cloud belts, moons, and maybe the Great Red Spot, Saturn’s rings and the Cassini division in them (the latter requiring good seeing) as well as its moon Titan, and Uranus and Neptune will be hard-to-find colorful dots.

Outside the solar system, the 70mm aperture limits you to a handful of deep-sky objects such as the Orion Nebula, some open clusters such as the Double Cluster and M35, and the Ring Nebula. There’s also countless double stars to explore if you’re into that. Otherwise, that’s it. The scope is simply too small to show you a lot of deep-sky objects.

Pros

  • A functional refracting telescope on a tripod for not a whole lot of money
  • Decent optics and accessories
  • Usable for terrestrial viewing

Cons

  • Mount is not the steadiest and is not suitable for an astronomical telescope
  • Low-power eyepiece isn’t low enough
  • Diagonal is mediocre optically

What's The Bottom Line?

To wrap this Astromaster 70AZ review up, while it is a complete working telescope, due to the limitations of the mount and accessories I would not recommend the AstroMaster 70. There are better telescopes (albeit mostly tabletops) in its price range, and you will become too frustrated with the mount for it to be worth the trouble.

Leave a Comment

Author Bio