A binocular chair is most suitable for cruising through star fields at up to about 20x. The Milky Way Lounge zero gravity binocular chair components have been fully tested with 10×50, and with 16×70 (shown here). An 82mm fieldscope, which zooms from 20x to 60x, has also passed our nighttime viewing test nicely. Lightweight 20×80 also perform well.
A general guideline for astronomy when compared to daytime usage, is that aperture (light gathering) is of high importance. In general, 50mm lenses are considered to be in somewhat of a sweet spot. However, as we age, our pupils may not dilate much at night. So for example, by choosing 10×50 rather than 7×50, the 50mm of available light coming into each lens, will be concentrated into smaller exit pupils. Less of the available light will miss one’s pupils.
For stargazing with binoculars, most choose individually focusing lenses, which tend to stay in focus, and are more rugged and waterproof. But these are not as appropriate for daytime use, such as for birding. For combined day and night use, choose binoculars up to 10x that have a central focusing knob which can quickly refocus both lenses together.
For mounting on a binocular chair it is convenient if there is a threaded mounting socket at the front between the two barrels. High magnification binoculars are always more challenging to stabilize on any mounting system. This is also true with a binocular chair. Actually a binocular chair can support these heavier binoculars, but the view through them may have an effect called “heartbeat”. This is where one’s pulse is transmitted through the chair and the mount, and then into the binocular view. A traditional mount for heavy high magnification binoculars like 25×100’s, is generally a sturdy tripod. The tripod provides stable views, but often at the cost of some discomfort, especially when the viewing elevation is increased.
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