Concentre visus question

[bottletopburly]

I ordered a concentre visus from Apm telescopes Germany which has arrived  one question for anyone using a concentre there is a small hole on the side of the barrel can anyone tell me of its purpose? Is it to let light in or for fitting an led ?  managed to find the sphertec pdf instructions online no reference to it mentioned, surprised that it came with no instructions, no end cap to protect the clear Perspex nose piece and no  protective tube considering it’s quite expensive for what it is . 

[johninderby]

It is so you can shine a light inside to illuminate the circles. Tried an led but it gave an irritating bright spot. Did see a thread on a German forum where they used a mini task light and it seemed to work better. Think it will work better with a more difuse not too bright light.

 

[bottletopburly]

Just now, johninderby said:

It is so you can shine a light inside to illuminate the circles. Tried an led but it gave an irritating bright spot. Did see a thread on a German forum where they used a mini task light and it seemed to work better. Think it will work better with a more difuse not too bright light.

 

Thanks John for clarification 👍.

[johninderby]

I’m thinking an led with a diffusing lens might work to avoid that bright spot. 🤔

[bottletopburly]

1 minute ago, johninderby said:

I’m thinking an led with a diffusing lens might work to avoid that bright spot. 🤔

I wonder if a small red led would work?

[johninderby]

Wonder if I could adapt one of these? 🤔

https://www.ebay.co.uk/itm/LED-Illuminator-for-finderscopes-polfinders-illuminated-reticle-eyepieces/164223780343?hash=item263c8005f7:g:9YkAAOSwdYFe0QZA

Edited November 19, 2020 by johninderby

[runway77]

 

[Cup of Tea]

On 19/11/2020 at 06:46, johninderby said:

It is so you can shine a light inside to illuminate the circles. Tried an led but it gave an irritating bright spot. Did see a thread on a German forum where they used a mini task light and it seemed to work better. Think it will work better with a more difuse not too bright light.

 

John, try the led again but first give it a good scouring with some Emery paper. This’ll give you a much more diffuse light.