What Eyepiece Should I Buy For My Telescope To Help Me See Jupiter

Hi all,

My Telescope is a Celestron Astro Master 70AZ. its specs are:

Aperture - 70 MM
Focal Length - 900 MM
Highest Useful Magnification i believe is 165x but im not sure

for information my telescope go to this link.
http://www.celestron.com/c3/product.php?…

i currently have 2 eyepieces a 10MM and a 20MM. when i look at Jupiter it seems small and distant with out any detail. i can only just make out 2 red storm bands on a very clear and dark night. i would like to buy a new eyepiece but im not sure which would be the best. i want the planet to seem closer and bigger so i can see more detail like the red spot.

Thanks Joe,

Best and most useful answer will get max stars.

Do you know what "Highest Useful Magnification" means? You can only magnify so much, depending on the aperture of your scope, because the aperture determines how much light the primary collects. A good rule to followw is that the maximum practical magnification for a scope is its aperture in inches multiplied by 60, or aperture in mm multiplied by 2.4. That's assuming your scope has good optics, and you're under a dark sky, and your scope has cooled down to the surrounding air temperature.

So the maximum magnification in excellent conditions for an excellent 90mm scope is about 165X, depending on what you're looking at. If you try too much magnification with a telescope, the image will be bigger, but it will be unclear. That's because you're magnifying not only the object, but the flaws in the scope, the movements of the atmosphere, etc.

Your 20mm will give you 45X, and the 10mm, 90X. So, a 6mm will give you 150X, about as high as you can go if everything else is good. A problem is that shorter, high power eyepieces have a narrower field of view. The object will be shakier as you try to move your scope, and will move out of the field quicker. Eyepiece quality can also make a difference to the performance of a telescope.