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Binocular Mount Degrees of Movement

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#1 Diego


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Posted 18 May 2004 - 09:22 AM

I'm having trouble understanding the degrees of movement specified on different bino mounts. Some are specified as 4 degrees of movement while other have 5 & 6.



#2 EdZ


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Posted 18 May 2004 - 10:07 AM

here's an explanation of the Six Degrees of Motion of a parallelogram mount.

The 3 motions typical of a straight in front parallelogram are
(1) Swing on the tripod = Right Ascension (rotation of the parallelogram around the vertical axis post on the tripod),
(2) Parallel arm adjust = standing height (this the parallelogram exercising up and down) and
(3) Mount head tilt = Declination or altitude. This is pointing the binoculars, or target aquisition that remains on target even when you move motion 2. It's what allows you to show someone else an object by raising or lowering motion 2. Of course, if you swing motion 1 left or right you'll need to swing back to the object. But the position of motion 3 will put you right back on target.

These are the three motions you get with a Virgo Skymount or any similar "stand in front of" mount. The Universal Astronomics Unimount also provides these three motions, although it achieves the 3rd motion a little differently.

You stand to the side of the UA Unimount Basic and it provides motion 3 with a large L bracket for the binocular mount platform. In addition, the UA Basic provides a 4th degree of motion. This separates the UA Unimount Basic from all the rest of the straight in front parallelogram mounts.

(4) Rotation - The 4th degree allows you to stand in one spot and sweep back and forth in addition to up and down, without swinging the whole parallelogram arm on the vertical axis post. This is done by providing an axle for the binocular L adapter screw plate to rotate left and right (actually fully around if you had small binoculars attached). If you're mounting a larger binocular with a center post, like a 20x90 or a 22x100, this screw plate, instead of have the L adapter screwed into it, has the post screwed into it and still provides the 4th degree of motion.

This 4th degree of motion is the single most important motion to allow seated viewing. Try seated viewing with a Virgo Skymount style pgram and attempt to view an object 20° or 30° to your left or right. What happens? Just to get the binoculars pointed at that object off to the side, you need to swing the entire parallelogram arm on the tripod. That puts the back end of the binoculars in mid-air about a foot or so off to the side of your chair.

You can add even more versatility to the Unimount Basic. A 5th degree of motion can be added by purchasing UA's articulated Deluxe L adapter rather than a rigid L adapter. For me this was a easy decision. Since I would have needed to spend $16.95 for a deluxe rigid L adapter and the UA deluxe with added motion was $29.95, I opted to get the additional motion.

(5) Plane Tilting - using an added Deluxe L adapter. Only for binoculars that need a typical L bracket, where the screw attaches to the binocular at the front of the bridge. This provides a screw with a swivel. Although it is screwed into and securely attaches the binoculars, it allows you to swivel the binoculars at this joint, like a plane tilting its wings. This provides for tilting your perspective to the field of view.

Going one step further, the Unimount Light "Deluxe" offers even one more range of motion.

(6) Articulation - Forward and rearward mount head movement. The 6th degree of motion in the Unimount Light Deluxe adds an elbow to allow the entire head, where the head attaches to the parallelogram arms, to bend forward and back. This allows you to literally bend, twist, swivel and cavort to any conceiveable position in the sky. It also gives more leeway in tripod placement alongside the chair. With this motion, there isn't any place you can't point the binoculars, all without moving your reclined or seated position.

this is a UA Unimount head that allows you to get two additional degrees of motion beyound the three basic degrees
The UA Unimount Basic head provides motions 3, 4 and 5.

With this head mounted with the elbow joint, you still only get five degrees of motion, but a different five than above. Above doesn't have the elbow. this doesn't have the deluxe L bracket.
The UA Unimount Deluxe head provides motions 3, 4 and 6.

If you put the Deluxe head with the elbow joint and the articulated L bracket on the same mount you would have all six degrees of motion. With all six, you can lay back in a recliner chair and look at any spot in the sky that you can turn your head towards, without ever lifting your head from the headrest. The binoculars will tilt, angle and swivel to any position that your eyes are tilted and pointed.

With this newer style UA Unimount head, head tension balance for any size and weight binocular is effortless. You can balance a 10# 25x100 such that swivel and tilt are smooth tilt is with one hand, swivel is with one hand and sweeping can be pushed along with your eyebrows.
The NEW UA Unimount head with slotted connections


#3 Rusty



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Posted 18 May 2004 - 09:24 PM

Think of the axes as providing two complementary features, location and tracking. The first three are really intended to get the binocs in front of your eyes, and the rest are to allow you to conveniently sweep them around without repositioning yourself or the entire mount. :bigshock:

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