Review of Celestron 20x80 Giant Binoculars

I recently purchased a pair of Celestron 20x80 giant binoculars, and so had an opportunity to compare them with some Tento 20x60 binoculars I already own. They were the standard model (number 71014), which means they had no case, no center support, and did not come with an L adapter. I purchased the latter, and I tested them over a number of clear nights in a rural location with dark skies as well as on a few clear nights in an urban environment.

On all occasions I used my binocular mount, as 20 x binoculars cannot be held steady enough to be useful.

My initial impression was that they had less contrast than the 20x60s, but clearly I saw deeper, with almost twice as much of the Orion nebula showing sometimes. This was their best feature. I enjoyed cruising the galactic supercluster in Virgo, and such treasures as M83, Eta Carinae, NGC253, Centaurus A, Omega Centauri and the Magellanic clouds were, well, heavenly. I fancy I could even see some shape to M1.

Eye relief was a healthy 18 mm, somewhat luxurious compared to the Tento 20x60s.

The resolution of the binoculars was about equal to the Tentos; neither binocular can quite split the trapezium or split Alpha Centauri. There was some coma off axis, and also a small amount of astigmatism, but for such fast optics at such reasonable prices, these defects were definitely within acceptable ranges, and did not diminish my enjoyment of the views.

I was extremely disappointed, however, with the baffling of the optics. So disappointed, in fact, that I returned the binoculars for a refund. My enjoyment was constantly dampened by reflections of off-axis objects, and I think lesser reflections severely diminished the contrast. I don't know why these reflections occurred, but a polished metallic philips-head screw located halfway down each barrel on the side nearest the center join may well have been the culprit. The barrels were equally flawed; if I had a reflection in one barrel on one side of a bright star, I needed only to go to the mirror position on the other side of the star to experience exactly the same reflection in the other barrel.

A kind retailer lent me some Celestron 20x80 deluxe binoculars to try (model 71011). These came with a fine case, center support, and a well configured adapter for a tripod. The eyepieces are different from the standard model, I believe, and the eye relief is slightly less at 16 mm. The overall construction is more robust than the standard model.

The optics of the deluxe model have resolution indistinguishable from the standard model or the Tento 20x60s, and the field shows a bit more contrast that the standard model, but much less that the Tentos. The most pleasing thing about this model is the relative lack of reflections in the optics, compared to model 71014. I saw only one small reflection in all my extensive testing, and the effect was not serious. Happily, the retailer was willing to sell these at nearly the US price and I have bought them.

One word of caution. The new model number for the deluxe model is 71015. I do not know whether this new model suffers from reflections as badly as the new standard model, but I would advise caution, especially with respect to possibly reflective screw heads in the barrels. Test them before you buy, or buy from a retail outlet that will give you a refund if you are dissatisfied.

Clear skies.