The Optical Tube Of Infinity 70AZ
The Infinity 70AZ is a 70mm f/10 achromatic refractor in the standard Fraunhofer crown/flint objective arrangement, like most achromatic refractors sold today. The f/10 focal ratio makes the chromatic aberration pretty tolerable and it has little impact on the views, but you will notice it. Optically, it’s pretty good in quality keeping in mind that it’s a cheap 70mm achromat.
The scope has an ample-length dew shield, but it isn’t painted very well on the inside. I recommend roughing up the inside with some coarse grit sandpaper (the dew shield comes off the scope very easily – just pull) and spraying some flat black spray paint on it.
The inside of the optical tube isn’t painted the greatest and it isn’t baffled particularly well, so glare can be a problem with this scope on/around bright objects. Also, nearby stray light will have an easier time getting into the tube.
The focuser on the Infinity 70AZ is a standard 1.25” rack and pinion unit, with a tension knob to adjust the force needed to adjust it. This knob is nice because you can tighten the focuser with heavy eyepieces/accessories or lock it down completely if need be (for example, if you’re using it around children).
The Infinity 70AZ comes with two eyepieces: A 26mm Kellner (Meade calls it the MA for Modified Achromat but it’s basically a Kellner) giving 27x and a 9mm Kellner giving 78x. Meade also supplies a 2x Barlow allowing you to achieve 52x with the 26mm Kellner and 156x with the 9mm Kellner – the latter magnification is slightly above the limit of what the scope can technically handle. The 2x Barlow is mostly plastic but does seem to be at least usable, although it really isn’t much more helpful than a dedicated 12.5mm eyepiece would be.
The Infinity 70’s supplied diagonal is an all-plastic Amici prism allowing for correct left-right images. The Amici design inevitably produces a spike effect on bright stars and the planets, but other than that it works surprisingly well. Care must be taken in handling it as it is somewhat fragile and is easily damaged.
The Infinity 70’s plastic red dot finder is decent in quality and more than adequate for aiming a 70mm telescope.
The Infinity 70’s mount is a simple double-fork altazimuth design with a metal rod to assist in fluid altitude motion – a design which has been around on inexpensive refractors since the 1950s and is highly variable in how well it’s actually executed. While not the most aesthetically pleasing and lacking slow-motion controls, the long tube of the Infinity 70 makes it surprisingly tolerable to simply push the tube to move the scope. Tensioning on both axes can be adjusted with two large plastic hand knobs which increase the friction on the bearings.
If you’re concerned about stability, adding a sandbag or brick to the accessory tray and/or filling the legs with spray foam are cheap, easy and effective ways to dampen the scope’s tripod.
For similar prices to the Infinity 70, there are a couple of other options you might want to consider.
Zhumell Z100/Orion SkyScanner – Significantly more aperture, slightly better eyepieces, and no chromatic aberration.
Orion FunScope 76 – More aperture and easier to use than the Infinity, at the expense of not being able to provide sharp high-magnification views.
Aftermarket Accessory Recommendations
We’d probably recommend upgrading the Infinity 70’s mediocre diagonal if you can. The Celestron 1.25” prism is a great bargain.
A 6mm “gold-line” eyepiece will provide 116x with the Infinity 70, and is a lot more comfortable to use than the stock 9mm or 6.3mm eyepieces.
What can you see?
The Infinity 70 will show you a lot of detail on the Moon, Mercury, and Venus’ phases, the ice cap on Mars when it’s at opposition, as well as Jupiter’s cloud bands, the Great Red Spot, and its satellites. Saturn’s rings and its moon Titan are visible, and on a good night, some of Saturn’s cloud bands and the Cassini division in its rings may be spotted. Uranus and Neptune are tiny bluish dots that will be difficult to locate without a lot of time consumed.
Outside the solar system, you’re limited by the Infinity 70’s small aperture. The Orion Nebula and many bright open clusters can be spotted, along with Andromeda and a few other galaxies, but don’t set your expectations too high, especially if you live in or near a city. Globular clusters, in particular, are likely to disappoint with the Infinity 70 – or any small telescope – even under dark skies, being simply too small or dim to resolve with a telescope below about 6” of aperture. A few of the large planetary nebulae such as the Ring and Dumbbell will show detail, but don’t expect dazzling colors or easy-to-spot features.
There are also a fair amount of double stars and asteroids which can be spotted with the Infinity 70, though they will remain points of light (if perhaps colorful ones) no matter what magnification – or telescope – you use.