Which eyepieces I can use it for best viewing experience using my existing telescope?

  • Telescope: Orion 09843 SpaceProbe 3,3 inch aperture(76mm), 700mm focal length, eyepieces - 25mm and 10mm focal lengths
    Hi, I am very happy and excited to see moon craters, Jupiter and Saturn. And planets like Mars, Venus, and Uranus are just looks
    like a brighter star but not able to see its surface color. Similarly Jupiter looks like white small ball
    instead of an orange surface. I am very much excited and want to go bit closer. So please guide me list of eyepieces that I can use with this scope at least to see Jupiter surface and big moon craters.

  • user5569

    user5569 Correct answer

    7 years ago

    Every scope has a minimum and maximum useful magnification (minimum on your scope is 18X and maximum is 152X - from specs on Telescope.com). Anything outside of those numbers will compromise your ability to see well through the scope. To figure out how best to make use of your scope within the restrictions of useful magnification, you need to start with how to calculate magnification from focal length.

    The magnification is equal to the focal length of the telescope divided by the focal length of the eyepiece. For example, your 25mm eyepiece would allow you to get 28X magnification (700mm / 25mm = 28X). Using the same formula, your 10mm eyepiece would allow you to get 70X magnification. For an easy way to get close to 152X, you could purchase a simple 2X Barlow. (700mm / 10mm) * 2X = 140X. For now, start with your 25mm eyepiece and get used to the night sky through it. You can always step it up a bit with other eyepieces later.

    So you want to see Jupiter? I think you should just barely be able to make out the dark bands in the atmosphere around 100X (so maybe a 6mm or 7mm eyepiece for your scope). You will definitely be able to see the Galilean Moons though. And speaking of moons, you should get a moon filter to cut down on the brightness when looking at our Moon. I've found it's best to observe the edge of the Moon where light turns to dark. The shadows created along the craters and mountains are magnificent to see. Enjoy!

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Content dated before 7/24/2021 11:53 AM