Orion AstroView 120ST

5.0 An Affordable Rich-Field Refractor

Low price, excellent optics, did I say low price?

For that price, I can't think of any!

I was looking for a scope to replace my beloved 10.1” Dobsonian. I’ve been getting older and the big scope was not much fun to move around any more. I found a great scope in Orion’s Astroview 120ST EQ refractor.

The 120ST has a 120mm (4 3/4-inch), 2-element objective lens with an f/5 focal ratio, which provides a wide field of view essential for Deep-Sky observing. It sits atop Orion's Astroview EQ German equatorial mount on an aluminum tripod. It comes with 2 of Orion's Sirius Plossl eyepieces: a 25mm for a magnification of 24x and a 10mm for 60x. It also includes a 6x30 finder scope and a "polar alignment" scope. The entire package sells for $519.95, a lot less than other short-focus refractors.

The images obtained with the 120ST are typical of short-focus refractors. Bright objects, especially planets and the moon are surrounded by violet halos due to the chromatic aberration inherent in even the best of achromats. But I didn’t buy this scope to look at planets or the Moon.

This scope was designed for viewing Deep-Sky Objects and this is where the scope really performs. The 600mm focal length makes for a beautifully wide field. Using the included 25mm eyepiece, I was able to view the Double Cluster in a single eyepiece field with lots of room for it to breathe. Using my trusty 30mm Tuthill Plossl, the field was almost 3 degrees across! I immediately replaced the useless, un-focusable 6x30 straight-through finder with an EZ Finder reflex sight. This scope doesn’t need a magnifying finder!

The 120ST provides beautiful views of DSOs. The Dumbell Nebula, M27 was prominent, courtesy of the higher contrast refractors are known for. The globular cluster M13 easily resolved into stars almost to the core with the included 10mm eyepiece. Though it wasn't designed to be used at high magnification, the 120ST easily split both components of Epsilon Lyrae with a 10mm Plossl and my 2x Barlow for a magnification of 120x.

Orion’s Astroview EQ mount, their “next up from the bottom tier” equatorial mount provides a solid platform for the 120ST. I found the aluminum legs pretty stable when extended up to ¾ the way out but I doubt I’ll ever be using them more than halfway extended. I like the hinged center brace for easy leg folding. The equatorial mount has easy to handle lock levers and very smooth motion. Slow-motion controls are very smooth with no backlash. I did notice that there was about a degree of play in the mount’s Declination axis. An email to Orion’s support department got me a reply in less than 24 hours explaining how to easily get the slop out.

In conclusion, the Astroview 120ST EQ refractor is a great scope for Deep-Sky observing at an excellent price.