http://www.telescopebuyingguide.com/blog/how-can-you-determine-the-focal-length-of-a-telescope/ Thu, 17 May 2012 20:07:30 +0000 http://wordpress.org/?v=2.7 hourly 1 http://www.telescopebuyingguide.com/blog/how-can-you-determine-the-focal-length-of-a-telescope/comment-page-1/#comment-2552 Geoff G Mon, 19 Apr 2010 07:40:27 +0000 http://www.telescopebuyingguide.com/blog/how-can-you-determine-the-focal-length-of-a-telescope/#comment-2552 When the Moon is back in the evening sky, point the telescope at it and measure how far the image of the Moon is from the end of the focuser. Then measure the distance from the end of the focuser to the objective lens. Adding the two together will give you the focal length. Zeiss made fine refractors with and aperture of 110mm and a focal length of 1650mm. I used one of these as a teenager, and it was one of the finest telescopes I have ever used. If this is such a telescope and in good condition, I would be interested in purchasing it. The catalog below may help you identify it.<a href="http://www.healthstorebargains.com/srch/srch.php?q=xtreme"> Geoff G</a> When the Moon is back in the evening sky, point the telescope at it and measure how far the image of the Moon is from the end of the focuser. Then measure the distance from the end of the focuser to the objective lens. Adding the two together will give you the focal length. Zeiss made fine refractors with and aperture of 110mm and a focal length of 1650mm. I used one of these as a teenager, and it was one of the finest telescopes I have ever used. If this is such a telescope and in good condition, I would be interested in purchasing it. The catalog below may help you identify it. Geoff G

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