Orion Model CT-80 f/5 Achromatic Refractor: A Small Telescope Capable Of Showing Hundreds Of Deep-Sky Objects Even The Entire Messier Catalog From A Dark Site
The telescope reviewed and discussed here is the Orion CT-80, an 80 mm achromatic refractor. However, it is no longer available following the closure of Orion Telescope and Binoculars in June 2024. Many other 80 mm refractors are available, including apochromatic (APO) and extra-low dispersion (ED) models, which are particularly well suited for astrophotography.
This 80 mm refractor telescope was a surprise birthday gift from my son, Brad, which makes it especially meaningful to me. Because of its sentimental value, I have no desire to replace it with a premium doublet or triplet.
This telescope was sold as an optical tube assembly only, without any accessories. I have always used an amici diagonal for use with refractors primarily for sketching deep-sky objects, scientifically correct.
Note: I did a review of this “very diagonal” for Orion, which was posted on their site until their closure.
When comparing the view to a premium enhanced mirror diagonal, I could not detect any noticeable difference. Test objects included double stars to evaluate resolution, as well as nebulae and galaxies to assess contrast. An excellent diagonal for anyone who wants to observe deep-sky objects with a scientifically correct, non-mirrored image.
An example as following of a correct oriented pencil sketch, indicating the cardinal points.
The Orion CT-80 has a beautiful pearl-white clear coated paint job and was ready to use out of the box. The scope works extremely well with a Vixen GP equatorial mount. The telescope and mount, including a three-pound counterweight can all be carried outside in one trip.
A good quality equatorial mount is just as important as the telescope.
From the “Observing Handbook and Catalog of Deep-Sky Objects” by Luginbuhl and Skiff regarding using a couple of 60mm refractors in the survey for the handbook…
“Despite its comparatively small size, this sort of instrument is quite useful for deep-sky observing. From a dark site all of the objects in Messier’s list are visible, and some of the best views of galactic nebulae are obtained with these telescopes at very low power.” Luginbuhl and Skiff
When focusing the telescope on planetary features or double stars, they would “snap into focus” which is an indicator of good optics.
My first target was the beautiful double star, Castor in Gemini. I started with 33x, but this was not enough magnification, but with the employ of a 2.8x Barlow, increasing the magnification to 93x the double was cleanly separated.
The next object was the trapezium in Orion. The four primary components were crisp and clean even at 33x. When increasing the magnification to 93x, the four primary stars were a beautiful sight indeed. The Orion Nebula appeared very bright with excellent contrast.
Galaxies M81 and M82, located in Ursa Major, have long been among my favorite galaxies. At 33× magnification, both fit comfortably within a generous 1.8° field of view, making for a truly beautiful sight!
Observing this pair brought back memories from more than forty years ago, to 1977, when I first viewed them through a 4.25-inch f/10 Edmund Newtonian on an equatorial mount. The portability of this telescope and mount will likely allow me to enjoy more frequent deep-sky observing sessions. It’s wonderful to revisit old favorites while making new memories under the stars.
Explore posts in the same categories: Orion 80mm CT-80 Refractor
