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Old 13-05-2019, 04:41 PM
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Ukastronomer (Jeremy)
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Ukastronomer is offline
Join Date: Jan 2019
Location: Llandysul, WALES, UK
Posts: 1,211
Originally Posted by mental4astro View Post
Hi Jeremy,

I'd say that looks like a barlow lens. My GSO barlow has a lens that looks just like that one - see pic below. Wind it into an eyepiece and see what happens - BUT DO NOT FIT IT ONTO THE END OF THE QUARK.

If you have one of those 1.25" focal reducers, you also wind it into the eyepiece and then the whole lot into the Quark. Do not fit the reducer onto the end of the Quark.

The reasons for not placing it onto the end of the Quark are 1, the light entering that lens may be too intense and cause it to heat up, 2, the location of the reducer will mean you won't have enough in-travel with the focuser even if the lens did not heat up.

I often use my 1.25" reducer with my Quark, and always by winding it onto the end of the eyepiece. Sometimes I also replace the barlow lens with the reducer lens of the barlow tube assembly to get an even greater magnification reduction. But be aware that this does not really give you a wider true field of view as this is governed by the aperture of the Quark itself. The magnification reduction the focal reducer provides will concentrate the image into a smaller size, which can help make it easier to see some details.

My "Quark kit" contains 25mm and 32mm plossls, a 1.25" focal reducer, & the tube of a shorty barlow sans the barlow lens. I also make use of the aperture stop cover that the scope's dust cover comes with as stopping down the aperture of the scope is another useful tool. I will often use all of these during a session with my Quark and ED80.


WOW OK then, won't do that, thank you
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