20x80 Light Weight Binoculars
Submitted: Tuesday, 4th July 2006 by Malcolm Shackleton
The binoculars arrived in my sleepy little village of Wongarbon (near Dubbo, NSW) two days after shipment. They came with a soft green case, a metal tripod adapter and instructions.
My first impression was that they were truly lightweight, I was surprised at how easy they were to handheld for a while as I gave them a quick "first light" at the scenery outside my front door during the day. The image was crisp and bright but I did notice some eyestrain due to a small interocular misalignment; this was easily fixed, however, by adjusting the left setscrew above the prism housing; only a small tweak of the adjusting screw was needed to merge both images. This was done at night using a star.
For the price I did not expect the binoculars to perform as well as they did the first night out with them. I mounted them on a camera tripod and was so absorbed with the views of so many DSO's through them that I was a little late for work (I was on night shift).
Saturn's rings were easily seen even though the planet was low in the west. The disc of Jupiter was obvious and the equatorial bands could just be discerned. However, these binoculars excel at deep sky observing. Omega Centauri was partially resolved as were other prominent globular clusters appearing very grainy. The Sorpious/Sagittarius region was stunning.
I have observed with these binoculars every night possible since i've had them. About 75% of the field of view is crisp and stars are pinpoints within the usable field. Bright objects show a little bluish?violet residual chromatic abberation but this is by no means intrusive. As with all binoculars I have looked through in the past, there is a degree of spherical undercorrection though much less than I expected and quite acceptable.
The excellent images these binoculars provide are a credit to the manufacturer?? and the price,$149, is incredibly low. These binoculars actually perform better than other, more expensive instruments I have looked through in the past. I am sure the good performance is due in part to the relatively long focal ratio, approximately f/5 as compared to the usual f/3.
Numerous galaxies can be observed through the 20x80 LW's but, surprisingly, some smallish planetary nebula are within its range: NGC 5189 in Musca for instance, which one would not usually think of as a binocular object but it stands out fairly well with averted vision. The Sombrero galaxy, though tiny, could be discerned with its sombrero shape and the Dumbell nebula (couldn't they think of a better name?) was beautiful; hourglass shaped with criss cross diagonal dark lines across it.
Is there a downside to these binocs? well, yes: the centre focussing support which holds the eyepieces is a little mobile; too much eye pressure puts either eyepiece out of focus. I have found though that when observing it is best to isolate ones bod from the binocs as much as possible, rolling the eye cups back allows you to view without touching the eyepieces thus avoiding both body shake and defocussing. This method, to me, is also more comfortable.
There is also the problem of the binoculars oscillating if they are just mounted with the bracket alone, the barrels need to be supported as well to avoid this. Once again this is easily remedied by placing a bar under the barrels on a mounting plate (see pic).
In summary, the 20x80 LW binocs are excellent value for the money and are to be recommended, (though perhaps not for a beginner who should start with something like 10x50's).
Spherical and chromatic abberration, though present, are minimal and unavoidable (due to short f/ratio and the fact that prisms introduce both to an optical system to some extent).
Mounted on a camera tripod these nocs are very convenient. Just pick the whole thing up by the tripod handle and go outside; my 8" scope is now temporarily redundant.
Much more can be seen through binoculars than some magazine articles would have you believe, it just takes patience and experience, the 20x80 LW's are exceptional in this regard; no telecope can give the same perspective to observing as these binoculars can. Learning how to observe and gaining experience are just as important as the instrument itself, perhaps more so. The 20x80 LW's, to me at least, are a main instrument in their own right. Who knows, you may find they override "aperture fever".
Cheers to you all