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Eyepieces to increase power for FirstScope #31041

Need our opinion on a telescope Optics Planet has on sale, go ahead and ask! Post some hints and tips on various telescope brands and configuration.

Eyepieces to increase power for FirstScope #31041

Postby opticsplanet.com on Tue Oct 12, 2004 12:12 pm

From: Caitlin

What lens should we buy to increase the power of the FirstScope? We have the 10mm and 20mm that came with the scope.
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Eyepieces for Firstcope

Postby opticsplanet.com on Tue Oct 12, 2004 12:22 pm

Hi Catlin

The magnification you get with an eyepiece is determined by dividing the focal length of the telescope by the focal length of the eyepiece. For your Firstscope, the focal length is 1000mm. The 20mm eyepiece, therefore, gives you a magnification of 50x and the 10mm eyepiece a magnification of 100x.

To increase the magnification of your first scope you have two options.

First, you can purchase an eyepiece with a focal length of LESS than 10mm. For the firstscope, a good choice would be the Celestron E-Lux 6mm, http://www.opticsplanet.com/celestron-t ... eries.html.

Second, you can purchase a Barlow lens, such as the Celestron Omni, http://www.opticsplanet.com/celestron-t ... enses.html which fits between the telescope and your eyepiece. This will double the magnification of your current eyepieces, which in effect turns your current 10mm eyepiece into a 5 mm eyepiece and your 20mm eyepiece into a 10mm eyepiece.
----------------------
Your personal optics expert
Joanie (Jne) K
http://www.OpticsPlanet.com
Phone: (888) 263-0356
Fax: (847) 574-6820
opticsplanet.com
Site Admin
 
Posts: 4044
Joined: Tue Sep 23, 2003 11:18 am
Location: Prospect Heighs, IL