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  1. #1
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    Default 35mm, 68 degree TFOV, in Dob8, M31?



    I tried to do my best to fit big objects like M31, M41, M44, and of course M45. I have bought 35mm (68 degrees wide angle)

    I have Dob8 (1200mm). So,this will give a magnification of 34X (with exactly 2 degree apparent field of view).

    Do you think that I can fit M31 Andromeda galaxy with 2 degree apparent field of view? or am I going to see only the core as a small white dot?

    I calculated the exit pupil, it is 5.9
    This means that No one can see better unless his pupil is dilated to 5.9mm, is this correct?

    Anyone has this type of piece? I think it is valuable WA EP for this telescope with perfect magnification and perfect true FOV. Pleiades will be really fascinating by this EP.

  2. #2
    Joe Lalumia's Avatar
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    Galaxies are TOUGH no matter which one -- usually you can only see the bright core. UNLESS you are at a very very dark sky observing site.

    In my 10 inch DOB I can get the entire double cluster and almost the entire Pleiades star cluster in the field of view using a 68 degree GSO 42 mm superview eyepiece. I can only see the core of M31.
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  4. #3
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    Hello Abdu,

    the M31 galaxy does not fit with its full extent even in my binocular 25x100. However, you my fix one of those galaxy arms, and the star cloud NGC 206.

    Best

    JG
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    Default

    Quote Originally Posted by Abdu View Post
    I tried to do my best to fit big objects like M31, M41, M44, and of course M45. I have bought 35mm (68 degrees wide angle)

    I have Dob8 (1200mm). So,this will give a magnification of 34X (with exactly 2 degree apparent field of view).

    Do you think that I can fit M31 Andromeda galaxy with 2 degree apparent field of view? or am I going to see only the core as a small white dot?

    I calculated the exit pupil, it is 5.9
    This means that No one can see better unless his pupil is dilated to 5.9mm, is this correct?

    Anyone has this type of piece? I think it is valuable WA EP for this telescope with perfect magnification and perfect true FOV. Pleiades will be really fascinating by this EP.
    M31 is more than three degrees wide, so no, you won't see the whole thing. However, even with a true FOV of three degrees, you would not see it all because it is too dim. You are just going to see the core. On a clear, dark night with a good wide angle eyepiece and dark-adapted eyes, you might be able to make out some of the spiral with averted vision.

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  8. #5
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    Default

    Yes, M31 is really disappointing, we really do need a dark sky.
    I can also use my 9X and 5 degrees finder if I am in really dark site.
    Many thanks

  9. #6
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    Hello Abdu,

    dont give up with the M31. Lots of training is required to fix anything in this smudge. It took years, to fix the outer spiral arm with 25x100, and later even with 15x85.

    Best

    JG
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