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  1. #1
    Mitchel1870's Avatar
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    Default Help! Orion XT10 Dob trying to connect to 35mm SLR



    Hi,

    New to this. Recently got a used 10" Dob Orion XT10. I am trying to connect my old Pentax 35mm SLR to it. I bought a Pentax K mount and a Celestron T-adapter (1.25"). I connected the Camera to the k mount then the t-adapter to the k mount and dropped it into the telescope. My tried to see how it focused on some trees down the street and I couldn't get it to focus in. Then I noticed I could pick up the basketball backboard in my nextdoor neighbors yard really nice so it seems my maximum distance for focus is about 40 ft or so. I wanted to take pictures of the moon, what piece do I need to get to focus out to 250,000 miles or am I doing something wrong.

    Also any 10 Dob owners get much detail on Saturn? I am going out at 9:00 pm at nights and having a hard time focusing or see detail. I know this year is a bad year to see the rings but I am not seeing much detail. It looks like a glow in the dark sticker for me. Is the atmosphere unsettled at 9:00 pm to see good detail?

    Mars was a orange dot with no detail.

    Any help is greatly appreciated.

    Ben

  2. #2
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    Default SLR and 10" Dob Orion XT10, need help

    Hi,

    New to this. Recently got a used 10" Dob Orion XT10. I am trying to connect my old Pentax K1000 35mm SLR to it. I bought a Pentax K mount and a Celestron T-adapter (1.25"). I connected the Camera to the k mount then the t-adapter to the k mount and dropped it into the telescope. I tried to see how it focused on some trees down the street and I couldn't get it to focus in. Then I noticed I could pick up the basketball backboard in my nextdoor neighbors yard really nice so it seems my maximum distance for focus is about 40 ft or so. I wanted to take pictures of the moon, what piece do I need to get to focus out to 250,000 miles or am I doing something wrong.

    Is there a lens I need to put into the t-adapter?

    Ben

  3. #3
    AustinPSD's Avatar
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    Default

    No lens is required (or for that matter, available) in the T-ring.

    Your focuser may lack sufficient inward travel to bring the camera into full focus.

    With that in mind, if you can focus on an object 40 feet away, you should be able to focus on an object at infinity.

    Go here for more information/help:

    Measuring Newtonian Reflector Back-Focus Distance
    CGEM 800 HD, NexGuide, Orion XT8 Limited Edition, Oberwerk BT-100, Canon 20D/20Da/T3i/60D/5D Mk III, various eyepieces, adapters, geegaws, widgets, and tiddlybits

  4. #4
    Mitchel1870's Avatar
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    Default

    It is acting like a set of macro lens but instead of a 3ft max range it is 40ft. I just can get anything to focus out over 40ft. I think you are correct about the inward travel. The celestron adapter (#93625) has about 1 inch of tube that fits in the eyepiece and another inch of black anodized aluminum that does not go in (~1.5" in diameter). So basically with out replacing the telescope with one that allows 6" of inward travel, I won't be taking any pictures unless I do it afocally.

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    Default

    If you're handy with a bandsaw or Dremel tool, you might be able to shorten the barrel end of the adapter to just what's required to engage the focuser's retaining thumbscrew, and buy yourself a little distance elimination.

    There are also potentially shorter adapters from:

    DIGITAL CAMERA ADAPTERS FOR TELESCOPES - Largest Selection!

    Is this a film, or digital camera?
    CGEM 800 HD, NexGuide, Orion XT8 Limited Edition, Oberwerk BT-100, Canon 20D/20Da/T3i/60D/5D Mk III, various eyepieces, adapters, geegaws, widgets, and tiddlybits

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    Mitchel1870 (04-15-2010)

  7. #6
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    Default

    It is a film camera.
    I contacted Orion and they suggested a special 2" Crawford camera mount that has no tube length to it. I think it will give bring me 1" or more closer to the secondary mirror plus maybe another .25" since the 2" to 1.25" coupling section needs to be removed from the focuser. It is nearly flat, just enough to fit in the 2" opening and enough threads to connect to the camera. For $12.95 it is worth the try.

    The did say that the telescope is optimized for optical viewing.

    I know Dobs are not great for astrophotography (unless i go another $1000 for a special tracking platform) but I was hoping for some cool moon photography.

    Thanks for your help.

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    Default Update?

    Quote Originally Posted by Mitchel1870 View Post
    It is a film camera.
    I contacted Orion and they suggested a special 2" Crawford camera mount that has no tube length to it. I think it will give bring me 1" or more closer to the secondary mirror plus maybe another .25" since the 2" to 1.25" coupling section needs to be removed from the focuser. It is nearly flat, just enough to fit in the 2" opening and enough threads to connect to the camera. For $12.95 it is worth the try.

    The did say that the telescope is optimized for optical viewing.

    I know Dobs are not great for astrophotography (unless i go another $1000 for a special tracking platform) but I was hoping for some cool moon photography.

    Thanks for your help.
    I have an XT8, and I'm thinking I will run into the same problems. Did the adapter allow enough inward travel, or have you had to settle for Afocal photography?

 

 

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