Synchronising Binoculars & Telescopes for Shared Viewing

Found an Amazing Object with Your Binoculars or Telescope? Share its Location Without Pointing and Explaining :-)

Identifying the Need & Defining the Problem

A ranger trying to explain the location of an interesting object to a tourist with binocularsI've often found myself in the following situation, for example when bird watching. I see something interesting, maybe a kingfisher under a tree some distance away, I use my binoculars to get a closer look then try to explain its location to my friend so he can look too, with 'his' binoculars.

The problem is that by the time I've managed to explain its location with lots of pointing and gesturing - "Its near that brown tree, the one with green leaves..." ;-) it's often too late and the object (kingfisher in this case) has disappeared!

I wanted something that would allow my friend(s) to share my viewpoint literally and to enable them to instantly locate and pinpoint the same object at which I was looking. This way, when one of us found something interesting, the other(s) could share it too, without several minutes of discussion and gesturing ;-) This is even more important of course when bird watching, since you don't want any unnecessary noise or commotion.

This is an idea I've had for about thirty years but I never got around to making a prototype and it may well have been invented by now. I have done a little research and I couldn't find anything relating to it, but if you are interested in taking up this idea, please carry out a more thorough research before investing any further time in it, in case it has already been patented or manufactured.

I developed (on paper and very roughly) a number of ways to achieve the desired functionality and also realised that the same technology would also be useful for sporting and other events; for use at sea in helping to share the location of people and boats in distress; and many other applications where two or more people need to quickly focus on the same object using binoculars or telescopes.

There are a huge range of binoculars and telescopes available of course, budget and expensive. This idea could be developed as an add-on to many of these instruments or it could be manufactured into a specialised range of products.

I also realise that a lot of handheld and other portable technology is available these days which could provide a solution to this problem (motorised tripods + CCD cameras + control equipment + tablet PCs, smartphones and such) but this is hardly practical for a hobbyist or amateur and would most likely be prohibitively bulky and time consuming to use.

Meeting the Need & Providing a Solution

Binocular and Telescope Viewpoint Synchronisation - Possible Methods.

  1. HMC5883L 3 axis magnetometer/compass.
  2. GPS.
  3. Laser guidance.
  4. Ultrasonic SONAR dual frequency for x and y relative positioning.

These are just a few of the potential methods which may provide a solution to this problem. In all cases some form of intelligence would be required in the form of a PIC or ASIC and some code (or even software for a more advanced/expensive version). Also, a communications link between devices (binoculars) would be essential, perhaps dedicated RF or standard bluetooth etc.

A man trying to explain the location of an interesting object to a group of bird watchersIn each case, the electronics, sensors and cells etc., need to be designed into an add-on unit and kept as small and light as possible.

Each set of binoculars would require a synchronising unit, so it should be easy to attach and use.

The alternative is to manufacture the system into a specific range of binoculars, perhaps with an audible alignment tone for pinpointing or even a mini heads-up display superimposed on the field of view.

In the case of an add-on unit an audible indicator would be a more realistic option for allowing an adjacent person to locate the same object (similar to the way a metal detector is used to pinpoint the location of a coin), using a pair of small earphones.

A magnetometer may be able to give a rough idea of an object location but is probably not accurate enough to be practical.

Commercial GPS although typically used for tracking and location ID is not accurate enough for this application.

Laser guidance would be excellent and relatively easy - a small portable visible red laser attached to each pair of binoculars. When a person is looking at an object, a second person can simply locate the red dot! However, projecting laser light all over the place (particularly when bird watching) is not recommended and therefore this method is not practical.

A more promising method would be to use a dual (two different frequencies to determine the relative x and y coordinates of the source binoculars) ultrasonic SONAR (similar to that used for vehicle parking systems) link for exchanging the relative positions of each pair of binoculars. Instead of trying to determine a finite position in space relative to the earth or an object, simply align one pair of binoculars with the next one; as long as they are fairly close together (within a metre or so) each user will see the same target area and object in the centre of their field of view.

Uses / Applications

  • Bird watching.
  • Sports events.
  • Search and rescue - particularly at sea or in the mountains.
  • Astronomy.
  • Most shared outdoor activities that require binoculars/telescopes.


Unfortunately this idea is very much a theoretical one. Only the problem/application is real in that it would be really useful for two or more people using binoculars/telescopes to be able to view the same object, without needing to explain its position verbally and/or with gestures :-)

Here is a typical 3 axis digital compass module but without experimentation I can't say whether it would prove to be accurate enough, in terms of compass bearing.

In order to monitor the elevation component of an objects position, a digital inclinometer module could be used. These are generally quite accurate and have a high resolution which should be more than adequate for this product idea.

Creative Commons Attribution 2.0Ranger and tourist photo by kind courtesy of U. S. Fish and Wildlife Service

Creative Commons Attribution 2.0Group of bird watchers photo by kind courtesy of Marjorie Lipan

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