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Erecting Eyepiece for Meade LXD-75

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  • 04-04-2011 9:40am
    #1
    squonk
    Registered Users Posts: 9,101 ✭✭✭


    Could anyone recommend an erecting eyepiece for use with a Meade LXD-75 Newtonian? One of the LIDL scopes actually.

    I traded up and sold my LXD to my neighbour who now wants to have a go at using it for terrestrial viewing. I never used it for that. I've an erecting prism for my new scope but that's not suitable for the Newtonian. Any recommendations you'd have would be appreciated, especially if you own a similar scope and have used an erecting eyepiece with it. I'd like not to have to make a best guess and ebay/buy something without being sure it'll do the job as it's my neighbour's money, not mine!

    Thanks for any help you can provide.


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    #2
    Popoutman
    Registered Users Posts: 1,363 ✭✭✭Popoutman


    Not really possible.
    The eyepiece orientation and the observer's orientation to the tube will determine the apparent orientation of the image in a Netwonian when looking at terrestrial objects.

    I've found that there are certain orientations that come close to 'level' but the contortions required makes it hard to keep looking.

    Personally I've just learned to switch off the requirement for 'level' and I kind of rotate the expectations for the image in my head, and it works for me. Then again I've ~20 years of looking in Newts..


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    #3
    squonk
    Registered Users Posts: 9,101 ✭✭✭squonk


    I know what you're saying and I do know that we probably can't do level, but I'd settle for not upside down in relatively normal viewing. There sin't going to be much to do about a crooked image.


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    #4
    Popoutman
    Registered Users Posts: 1,363 ✭✭✭Popoutman


    it's worth trying an erecting prism aligned so that the eyepiece is pointing along the scope axis away from the primary mirror, so that the viewer's eyes are looking down towards the primary mirror cell, and the focuser is parallel to the ground.
    You may have to use the 2" focuser with a 2-1.25 adapter in order to get the in-focus required. At least the 6" LXD75 OTA has the capability to do this.

    Newtonians are unfortunately just not the most suitable for terrestrial viewing.


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    #5
    squonk
    Registered Users Posts: 9,101 ✭✭✭squonk


    Thanks Popoutman. I'd try that except that the person isn't that used to scopes yet really. I'd like to keep it 'uncomplicated'.

    Am I correct in thinking that eye pieces exist that are similar to the Meade4000 barlow lense and are essentially a corrector sitting at the bottom of a 1.25" barrel that you can then fix your eyepiece into? Something like that would be ideal as I fear the gentleman in question isn't going to get very deep into astronomy and wants to just look at the moon, a few planets and what's going on out to sea.


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    #6
    Popoutman
    Registered Users Posts: 1,363 ✭✭✭Popoutman


    Those are only suitable for scope with the eyepiece and focuser at the rear of the scope, but if the user is willing to accept that these will only rotate the image 180 degrees with a little loss in quality then it's an option for sure.
    Another option for those types of scopes with the focuser at the back (refractors, SCT) is the likes of this 45degree diagonal : http://www.opticsplanet.net/meade-928-45-erect-image-diagonal-prism.html or a 90 degree Amici prism diagonal.
    However none of these will work as expected with a Newtonian.


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