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Old 13-08-2020, 09:17 AM
DwightHuth (Dwight)
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DIY Barlow

I made my own Barlow DIY lens using plumbers tubing for a sink. The tubing is hard plastic and easily fastens to the eyepiece using the twist connector.
The tubing is seven inches from the bottom of the eyepiece to the top of the lens that can be screwed into the bottom of the tube opposite the eyepiece.

What type of magnification am I getting with the seven inch DIY Barlow Lens?

Here is a photo of the DIY Barlow Lens.

https://i.ibb.co/s1Z9Cqh/20190824-203804.jpg

This photo is the DIY Barlow being used as an extension without the lens.

https://i.ibb.co/WVK07Lg/20190824-180334.jpg

Last edited by DwightHuth; 13-08-2020 at 09:24 AM. Reason: Added correct image size
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Old 13-08-2020, 11:25 AM
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Merlin66 (Ken)
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You donít mention the focal length of the Barlow lens.
You can measure this by marking a card with a circle twice the clear aperture of the Barlow lens.
Point the lens towards the Sun, when the image fills the circle, the spacing is the focal length.
To get x2 magnification the eyepiece/ camera should be positioned at 1/2 the Barlow focal length behind the lens.
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Old 16-08-2020, 12:15 AM
DwightHuth (Dwight)
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The length of the tube from the bottom of the eyepiece to the top of of the lens is 7". I have a 3x and 5X Barlow in my kit already. Would my DIY Barlow be similar to staking a 2X and 5X Barlow on top of each other?
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Old 16-08-2020, 07:45 AM
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Merlin66 (Ken)
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Dwight,
You need to measure the focal length of the barlow before you can calculate the magnification.
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Old 17-08-2020, 10:56 AM
DwightHuth (Dwight)
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Quote:
Originally Posted by Merlin66 View Post
Dwight,
You need to measure the focal length of the barlow before you can calculate the magnification.
I just realized that I will have to put a lens in the DIY tube in order for it to be an effective Barlow Lens. Right now the tube is nothing more than an extension tube.

Does anyone know of any good Barlow Lens and where I can purchase them from?

The overall length of the tube is 5 1/2 "

I would have to take a guess, but the focal length of the DIY would the length between the bottom eyepiece lens to the eyepiece in the Barlow.

The length between the eye piece and the Barlow lens will eventually be five inches.
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