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  1. #1
    lamphater's Avatar
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    Default Need help w/low Magnification



    I am thinking I would like to buy a very low mag, wide field eyepiece for scaning large areas of the sky. I was thinking of the 41mm Panoptic.

    I am not sure if this will work with my scopes.

    10" -F4.7 F/L 1200

    102mm -F6.9 F/L 710

    My thoughts after reading reviews is that this eyepiece works well on longer focal lengths like in SCT's and Mak's.

    What is the deal here?

    Is it as simple as one of those extenders for more backfocus?

    I am sure some of you can help me here and advice would be much appreciated.

    Thanks in Advance, LAMP

  2. #2
    RussL's Avatar
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    Default

    Lamp, I think it'll work. It will indeed give you low power, about as low as you can go. From what I've read the catch might be in the wide apparent field of view. In a fast scope, there's a lot of curvature going on, moreso than in a slower scope. I've heard tell that that is why a wide eyepiece has to work harder, so to speak, to keep things sharp as far as possible off axis toward the edge. I guess the eyepiece also has more curvature going on than one with a narrower field of view. Wish I could tell you more, but I don't know the technical part well enough to say for sure.

    Mainly, I've heard that wide eyepieces work best in longer focal ratio scopes. Yet, many folks use them in fast scopes with good results. Just be aware of the possibilties.

    However, I've also heard it said that in order to beat the odds it helps to pay a lot for the eyepiece since it costs more to make one that will be as optimal as possible. You can't go wrong with a Panoptic, if you can get one. I hope someone who knows more will come along to say this better. These are just the general comments I've heard, and I hope I'm remembering it right. I don't have a wide eyepiece--yet. But I'm gonna be getting some for my f5. It it's a tad blurry at the edges, I wont mind. I just like having that view there whether I'm looking directly at it or not.

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  4. #3
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    Default

    Hi LAMP,

    The Televue Panoptic eyepieces provide excellent views in my F/4.964 telescope. This past week a friend of mine brought his 35mm and 27mm Panoptic eyepieces over and we compared the views to my Televue 32mm Widefield eyepiece. The Panoptics provided slightly better images with stars quite sharp to the edge of the three degree wider field of view.
    The 41mm Panoptic eyepiece will work very well with your 102mm F6.9 telescope. It will provide a bit too large of an exit pupil in your 10" F4.7 dobsonian telescope. A 35mm Panoptic eyepiece will be much better suited for your dobsonian.
    It is okay to have an exit pupil larger than that which your eye will admit. The drawbacks are that objects will look like they are being observed with a smaller aperture telescope and that in a reflector the diagonal mirror will be much more obvious in the eyepiece.
    A general rule of thumb is to take the number 7 and multiply it by the focal ratio of your telescope. If you are located in a lot of light pollution or if you are significantly older than twenty years of age then you might be better off using the numbers 6 or even 5 as the multiplier instead of the number 7.

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    WOW,

    Two very informative posts from Russl & Star Drop!!
    Thank you both for the free education. This Forum is a great place for me to learn.
    Great stuff guys, just keep it comming.

 

 

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