National geographic 40 mm telescope

Joe Lalumia aka TelescopeMan

• 3186 Answers
• Posted on Jan 04, 2009

SOURCE: National Geographic NG70CA Telescope .... help with

Your small telescope will never get beyond about 100 power --- the maximum resolution is calculated as 50 times aperture under perfect conditions!

Use the eyepieces with the LARGEST numbers only and don't use the barlow.

SOURCE: I need instructions for the National Geographic Rock Tumbler.

Complete instruction manual to be found following the following link: http://www.sbdirect.biz/_download_files/NG09.pdf (my son also lost the instructions and I had to search the web to find another copy...

Joe Lalumia aka TelescopeMan

• 3186 Answers
• Posted on Jun 18, 2009

SOURCE: no manual for national geographic NG6005N telescope

You won't find a manual for that small telescope --- however Meade probably has one similar to yours-- go here and download a manual for free-

http://www.meade.com/manuals/index.html

SOURCE: PNY bonus of National Geographic download

Here's the correct link for your free downloads...

http://nationalgeographic.pny.com/

SOURCE: NATIONAL GEOGRAPHIC TELESCOPE NG76AZ where

Do NOT attempt to look at the Sun through a solar filter! These can crack from the heat and you will be blinded instantly.

Most telescopes use a standard fitting eyepiece with a 1.25 inch outside diameter barrel. You can measure the mount where the eyepiece goes to make sure that yours is this size, then search on eBay or Amazon for "1.25 eyepiece" and you will find many available. None of these will be made by National Geographic, but any make will fit.

The other variable will be the focal length of the eyepiece, which is what determines it's power. The power of the scope will be the focal length of the main objective divided by the focal length of the eyepiece, so a 9mm eyepiece will give a higher magnification (and be dimmer and harder to focus and find objects) than a 20mm eyepiece. It is usual to have two or three different focal length eyepieces for viewing different objects.

You will find a large variation in prices, which is partly due to the difference in quality and type of construction of the eyepieces. Kellner eyepieces are simple and cheap, whereas Possl or orthoscopic ones are more complex and cost more. There are reasons why people will pay more for the better eyepieces. Avoid eyepieces marked with the letters "H" or "SR" before the focal length.