July 26, 2010


I purchased 4-inch (25x100) binoculars in July 2009 only for visual comet hunting. My purpose was carry them with me whenever I go out side the city to sweep the evening western skies after dusk. But I couldn’t use the binoculars at their full extent. The problem was that I was using them without a viewfinder. The binos magnifies 25x and has a FOV (Field of View) of 3 degrees. It was very difficult for me to find the object’s exact location whenever I stumbled upon them. It wasted most of time of my comet hunting sessions. Also the binocular was useless during 2010 Messier Marathon as I couldn’t find most of deep-sky objects. I believe in fast observation and spending much time in observation rather than wasting time in finding objects. Those who are using 25x100 binos must have faced problems of locating deep-sky objects and faint comets. They must have to star-hop to get on some particular deep-sky object.

I decided to solve this problem. Firstly I tried my telescope’s finders and tried to build some kind of support system to fix the finder. I wanted to fix the viewfinder on the central aluminum rod which joints two monocular but could not make it done. Finally I got solution while I was surfing the website of Indian Telescope Manufacturer, Tejraj & Co. I found that a bracket is available that can be fit over a telescopic tube. The bracket actually holds a view finder. I also found that a ringed bracket is available that can be fit over a 110mm diameter telescopic tube to support a view finder piggybacked. My Binoculars’ O.D. (Outside Diameter) is 115mm. The ringed bracket comes with two pieces (half-ringed shape) that joints each other with plastic screws. I ordered one bracket and one 7x25 straight-finder scope.

I received the parcel on 26-7-2010. After opening the packet, I tried to fix the bracket in the left sided monocular of my binos. It was rather shorter! However I could fix it with the help of a black wire that comes with cell phone’s charger. I carefully fixed the finder and set the binos on tripod stand.

-Rahul Zota

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