Sep 30 2008
Is it possible to put a monocular in front of a binoculars’ eyepiece to boost the binoculars’ magnification?
Simsim asked:
I have a 7×50 Orion Scenix Astronomy pair of binoculars. I’m not happy with the 7x magnification.
I thought that if I can get a tiny monocular, say 3X20, then I can put it in front of one of the binoculars’ eyepieces. Hopefully getting a 7*3=21x magnification.
I have a 7×50 Orion Scenix Astronomy pair of binoculars. I’m not happy with the 7x magnification.
I thought that if I can get a tiny monocular, say 3X20, then I can put it in front of one of the binoculars’ eyepieces. Hopefully getting a 7*3=21x magnification.
Is this possible?
Any recommendation on the monocular(aperture, magnification, brand etc)
Thanks in advance.
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3 responses so far
The focal length is an important factor. It would never work, because monoculars are not designed to focus on such a short length. I don’t know why you’d be unhappy with 7 power for astronomy, however. Most astronomical objects that you can’t see with extreme magnification are seen with light-gathering instead.
While this is theoretically possible, the image would be so dim as to be worthless. Enjoy your binoculars for what they are: a tool for wide-field views of space, and save your money for a telescope, properly designed for more magnification.
Yes, BUT the way you’re trying to boost your viewing experience is all wrong. When the magnification of a lens system increases, (which is one way of thinking of telescopes, or binoculars), the field of view decreases with a decrease in the brightness of what is being viewed.
I also own a pair of 7-power 50mm. binoculars.
This will maybe give you an idea of what I’m talking about.
Let ( n )= the number of objective lenses gathering the light in.
Let ( D )= the diameter of the Objective lenses in millimeters.
Let ( M )= the Magnification of the Objective lenses.
You have a 7-power 50-millimeter pair of binoculars and you want to put a 3-power lens into this system to bump the magnification up to 21-power.
In your case currently,
( n )=2,
( D )=50, and
( M )=7
then n times ( D squared )/( M squared )= the apparent brightness
therefore ( 2 times 50 squared )/(7 squared )= (2 times 2500)/49
=5000/49 which gives an apparent brightness of about
***( 102 )***
when you increase the magnification of the system from 7 to 21 as you’re thinking, then,
( n )=2,
( D )=50, and
( M )=21
therefore ( 2 times 50 squared )/(21 squared )= (2 times 2500)/441
=5000/441 which gives an apparent brightness of about
***( 11 )***
therefore when you increase the Magnification of the system 3-times its current value you decrease the apparent brightness and also the field of view about 10-times, leaving you with a much dimmer image than you started with.
For the apparent brightness, and the field of view to stay the same, whatever amount you increase the Magnification by, you’d also have to increase the Diameter of the Objective by.
At one point I owned the following telescopes, a
8-power 10mm.apparent brightness about ***1.56***
15-power 30mm.apparent brightness about ***4.00***
30-power 30mm.apparent brightness about ***1.00***
20-60-power 60mm.apparent brightness about ***9 to 1***at its minimum magnification, it yielded the brightest image of them all.
22-150-power 60mm.apparent brightness about ***7.44 to 0.16***at its minimum magnification, it yielded the 2nd brightest image, and at its maximum magnification, it yielded the dimmest image of them all.
To do what you’re trying to do, you’d have to increase the diameter of your objective lenses by the same amount you’re trying to increase the magnification. And this doesn’t even take into account either the focal lengths of the lens system of your binoculars, or of the monocular which you thought of using.
I hope this information helps.