Used Orion ED 120mm refractor

This is an Orion 120mm ED refractor in only fair condition overall.  This model is probably about 15 years old, give or take.  Let's start with the tube:  it's in rough shape.  It was left out in the sun, A LOT, as previously black metal fittings have faded completely to bronze.  It also has rusted in certain spots, which indicates that it was left outside and dewed over and then not wiped down.  Looking inside the tube, there is no baffling whatsoever.  The previous owner was not kind to this scope.  

HOWEVER, regardless of the poor treatment of the tube, the optics are clean and clear and in very good shape.  The objective lens cell is completely removable with the dew shield - the whole assembly just unscrews. There is some spotting of the coatings in between the two lens elements, and a few specks of dust, but otherwise, the optics are clean and clear.  See the photos.  

If you can get past the poor condition of the tube itself, the optics will still be able to deliver you some stunning views/data.  

We have taken all of these significant condition issues into account in the pricing.  As a result, this scope is an absolute steal at only $450!!!

This is the bare OTA, with no diagonal, finder, or eyepieces.  It includes mounting rings attached to a Vixen dovetail that has rust on it.  It also has a focus motor, which we have not been able to test.   

Because of the size of this telescope, we cannot ship it to you:  it is available for in-store pickup only.  There are no returns on this item.  

The Orion 120 ED makes up with aperture what it make lack in perfection, and yet with the 900mm focal length the useful fields of view are broad enough and the high power performance good enough that anyone who buys this should be pleasantly surprised.

This Apo can 1. deliver the light gathering and high contrast resolving power necessary to reveal many celestial objects with a very natural almost three dimensional appearance, 2. can provide a wider span of Field of View than any Reflecting or Catadioptric design with an aperture that can show similar detail, and 3. can cross to well above the critical 200x minimal threshold of planet and lunar observing that reveals subtle details and changing features from night to night.

The 120mm ED approaches 280x in term of light gathering power over the unaided human eye and this is about a 1.44X increase over the throughput of its smaller cousin the Orion 100mm ED. It is possible to glimpse the entire "Messier Catalog" and a number of "Hershel Catalog" deep sky objects even from reasonably moderately light polluted suburban skies. One of the finest advertisements ever published for the smaller 4 inch Apo telescope is the book Deep-Sky Companions: The Messier Objects by Stephen O'Meara. To produce the highly detailed drawings of these deep space objects Stephen observed with an older generation TeleVue "Genesis" telescope of 500mm f5 with Fields of View approaching 5 degrees! This book is among the best advertisements for the versatile, readily transportable fast refracting telescopes. He equipped the telescope with only a modest selection of accessories: TeleVue 22mm "Panoptic" eyepiece 23X, 2.85 Degrees Actual Field of View), a 7mm Nagler eyepiece (71X, 1.08 AFOV), and a TeleVue Barlow lens to increase the magnification by 1.8X. The 120mm ED views can surpass those shown in O'Meara's book although it can not attain as wide a field of view as the Genesis, but for many who seek their first practical Apo the 120mm ED will do nicely. And if one is willing to step up to the effort of setting up a German Mount, then this is even more reason to put manageable aperture on that platform.

Company Seven recommends the 120mm ED for variety of applications including:

• Astronomy
  • versatile low to medium power visual telescope (16X to 300X)
  • photo-guide telescope
  • astrograph (with optional Field Flattener/Telecompressor better than 3 degrees!)
• Terrestrial
  • Low Power, Wide Field Terrestrial observing
  • Use as a versatile Ultra-Telephoto Lens (720mm f/6, 900mm f/7.5 or greater)

ED Glass the air spaced doublet objective lens of the 120 mm ED is designed to provide precise optical color correction, and it is multicoated to improve contrast and transmission across the visual spectrum. The objective lens incorporates an Extra-Low Dispersion Fluorocrown FPL-53 extra-low dispersion "ED" optical glass from Japan; this is a glass crown element developed under laboratory conditions. Colors of the spectrum have differing wavelengths, to see this notice how in a normal optical glass prism the red and blue rays are bent at slightly different angles as they pass through. This dispersion results in color fringing that when looking through a telescope or telephoto lens usually appears as a slight violet halo around one object that contrast one against the other, and this can cause an overall lack of sharpness. In camera normal and wide-angle lenses this is imperceptible or can be corrected with other techniques, but telescopic lenses magnify the variation in focus between red and blue light rays. So the camera lens making companies (Carl Zeiss, Nikon, and Canon) pioneered Extra-Low Dispersion glasses and Fluorite crystal technologies to solve this problem. This ED glass material provides reduced chromatic aberration over similar f ratio achromatic designs in portions of the spectrum from the D (yellow), through C (red), F ( blue) and G (purple) Fraunhofer lines.

Left: Business end of the Orion 120mm ED OTA (91,020 Bytes).
Click on image to see enlarged view (363,312 bytes)

This technical materials improvement improves one of the critical aspects of refractor performance: reduction of chromatism. This means when one looks through the 120mm ED to a study a black bird contrasted against a light blue sky, or a green leaf in the distance, or the planets or Moon overhead then there is no perceptible false color fringing or violet halo around these objects; the colors are more properly rendered and finer details are seen. And since the colors ore more precisely brought to focus, then the color intensity is better - the more subtle variations in the tonality of the bands on Jupiter are more obvious, and fainter stars may be revealed than in a similar aperture achromatic telescope.

What does it do? the Apochromatic refractor has been the traditional choice of visual astronomers. The combination of thermal stability, best view per pound of telescope, clear high contrast images, and apparent brightness can surpass more bulky designs such as the 8" Catadioptric and Newtonian telescopes. And the versatility of field of view and range of magnification is unrivaled by all other telescope designs.

This portable telescope provides stunning lunar and planetary observing; it can clearly reveal the major changing features on several planets through out observing seasons. You may imagine you are seeing details on the moon as if you were in orbit - even though the smallest object you could see with this telescope will actually be about 6 kilometers in diameter! And yet it is so compact and lightweight that a child can manage it.

The focal length of the 120mm ED is made even shorter, and the image quality improved with the optional focal reducer offered by Company Seven to our 120mm ED customers. This photograpic accessory delivers a wider field of coverage at f6 for terrestrial or astrophotography. These and out other Telecompressors provide added versatility for CCD imaging too!

2 inch Focuser aside from good performance at higher magnifications the telescope is quite at home sweeping the Milky Way, or Comet hunting. This is an easily manageable telescope with the unobstructed 120mm light gathering power and fields of view to recognize many of the popular bright deep sky objects. Tease subtle details out of the Great Nebula in Orion, see the spiral nature of the Andromeda Galaxy. Seek out more deep-sky wonders including Star Clusters, and Planetary Nebulae, etc. Try a TeleVue 55mm Plossl eyepiece on for size, working at 16x provides a true field of 2.9 degrees. The combination of field of view and light gathering power will make hunting the large deep sky objects very rewarding, even more so with optional light pollution rejection filters. Or take the plunge into awesome perfection of the TeleVue 35mm Panoptic at 26X showing 2.45 degrees - suitable for astronomy and nature watching, with a view that is crystal clear across the entire field of view!

Notice the innovative arrangement of the Crayford style Focuser and Lock; this a low maintenance friction drive which eliminates the conventional focuser's use of a Rack and Pinion and need for lubricants. The four adjustable set screws applies pressure to the Focuser Pinion to attain the proper adjustment of the friction control, this adjustment is critical. And a Drawtube Lock is also provided for astrographic applications.

120mm ED telescope lightweight, yet adequate mechanical construction of metal and aluminum:

• Machined Aluminum, Satin Black Painted Front Cell
• Cast Aluminum, Gray Textured Painted Focuser
• Rolled Steel, Metallic Gray Painted Optical Tube
• Fully Baffled with interior finished in AR Black
• 2" diameter rack and pinion focuser. Moves with smoothness and precision, with no hint of backlash or play
• Focuser draw tube includes reducer to accept furnished 1.25" (31.7mm) accessories
• Focuser tension adjusting/locking screws permit the user to secure focus with heavy loads attached (such as a film or CCD camera) so that focus will not accidentally change over the course of an exposure or viewing session
• Quick Release Bracket for optional Orion Finder
• Dew Shield - threads on and is easily removed
• Slip on Lens Cover with 52mm diameter on axis Aperture Stop