Binoculars, What is the Minimum



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Date: 3-17-2003
Abstract: Which binoculars are best for which users.  The author explores different models that he has had experience with and offers advice.

Having accumulated 4 pairs of binoculars, 3 of which were purchased specifically for backyard astronomy, I have come to some conclusions about binoculars and their use to observe the night sky. Before I begin I should make it clear that none of these 4 pairs coast more than $150 to buy, so I'm not able to talk about premium binoculars such as the
Fujinon or Miyauchi or other high-end binoculars, but those are probably outside the realm of interest for this site in any case.

First, here is a quick list of the binoculars referred to in this article:

Tasco 10x50 Model 2023 (had these for years; really cheap; have recently seen this same model for sale, new, for $40!)
Nikon Action 12x50
Pentax PCF V 16x60
Orion 15x70 LW

The old Tasco 10x50 binocs are just fine for giving a broad view of the night sky, but you can't see much of individual objects such as the Messiers. I used these quite a bit as a finder for my telescope before adding to my binocular collection. They're light weight, purely hand-held, have an unusually wide & pleasing field of view, and the optics are more than satisfactory given the very low price.

More recently I acquired the other 3 binoculars shown above; the first of these new ones for me was the Pentax 16x60. These have been OK, but they have a very narrow field of view and there is something a little funny about the views of the night sky which make them not entirely pleasing. Perhaps they are slightly out of collimation, perhaps not, but whatever the case, they have been used less and less recently.

Next came the Nikon 12x50s, purchased mostly because they were available, used but in pristine condition, at a good price, and they have the tripod mounting threads, something not present on the old Tascos which these were intended to replace. Optically these are a bit
better than the old Tascos, but they didn't knock my socks off.

The most recent addition, the Orion 15x70s, purchased used but in good condition, have, alone among these 4 pairs of binoculars, provided me with what I was looking for all along. Even though these are the light weight Orions, they are always tripod-mounted so as to avoid the inevitable shakes. These are the binoculars which have caused the Pentax 16X60s to remain in the case, despite the increasing seagull-distortion effect on stars in the outer 30% or so of the field of view.

The most important conclusions I have drawn from my experience with these various binoculars are:

1. For viewing individual night sky objects such as the Messiers, other asterisms and simply to bring more of the celestial wonders to your eyes, BEGIN with 15x70 binoculars. Even at a touch lower power, the light-gathering ability of the 70mm objectives seems to be significantly
greater than that of the 60mm Pentax binocs and deliver the kind of binocular views of the night sky I'd been hoping to achieve. To tell the truth, the 16x60 Pentax binocs are going to be sold; they are good & will serve the buyer well--until he or she tries a 70mm or 80mm pair!

2. Keep a pair of low-power, wide field binoculars like the 10x50 or 12x50. These are wonderful for scanning the heavens, locating specific areas and brighter objects, and serve well as a hand-held spotting scope when working with a telescope. And they are of course also very good for daytime, terrestrial observing.

In other words, if I knew at the beginning what I know now and had no binoculars at all, I would buy a pair of 10x50 or 12x50 binocs, plus the 15x70s, and that would be that. Binocular aperture fever will likely take me to an 80mm pair and perhaps even to the monster 100mm level, but for someone new to binocular astronomy who also doesn't want to spend a huge amount of cash, I'd suggest cutting out the middle man and start with at least 15x70 binocs for satisfying night sky observing. Orion, Oberwerk and a few others offer 15x70 binocs, so check 'em out.

Submitted by Chris Rasmussen

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