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Thread: Is this a normal collimation view Celestron 127EQ ?

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    Default Is this a normal collimation view Celestron 127EQ ?



    With MANY THANKS to the good folks who previously posted how to access the primary mirror on this thing I successfully applied a nice commercial center triangle to the primary mirror and installed a full set of Bob's Knobs to the telescope.

    I picked up a Cheshire Collimator and after a considerable amount 'knob fiddling' over a pair of work sessions I 'think' I 'may' be close to something vaguely resembling collimation? The following is my attempt to describe in words a picture I don't have, so be patient - lol

    Had it out over the weekend in pretty clear conditions and got a bright star ( no idea which one - lol) centered in the eyepiece. With the star adjusted to be way out of focus I see, slightly off center to the left and up, a dimmer clear disk reflection of the primary mirror with its three mounting points visible plus the vanes and center circle of the secondary mirror central to the image. Upon focusing the star the best I can for a clear image that earlier image slowly condenses disappearing into a centrally visible focused dot of light.

    Have I just described what someone who knows what they're doing expects to see or do I need to continue my feeble collimation attempts?

    All assistance greatly appreciated and best delivered as one would explain it to their family pet dog - lol
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    Default Re: Is this a normal collimation view Celestron 127EQ ?

    Firstly your scope has a corrector / barlow lens inside the focus tube so using a Cheshire or any other tool will be very difficult one has to remove the corrector before alignment of the mirrors (with it in place the image is too small ) once removed then collimate as a normal newtonian , remember to replace the corrector lens in the same position , ie dont flip it the other way round!
    Lots of videos around but perhaps someone can post what a star test should look like
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    Default Re: Is this a normal collimation view Celestron 127EQ ?

    Prior to using the Cheshire I did remove that lower lens, allowing for potential rookie mistakes, how can I verify if that Barlow is upside down?

    And is what I am seeing with an unfocused sky object typical?

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    Default Re: Is this a normal collimation view Celestron 127EQ ?

    I have found a couple seemingly very good interweb sites that provide easy to understand depictions of using stars to collimate and will try them the next time the telescope and I are together. In truth the unit was a gift to my married 45 yr old son who lives about 35 miles away...or as he puts it, I store MY telescope at his house - lol.

    The deeper my self-education in astronomy and telescopes goes, the more I kick myself in the backside over how little homework I did when I bought the 127EQ in the first place. There sure are a whole lot better ways I should have spent my money or saved a little longer to buy better. Live and learn. But being old and stubborn I WILL get this beast functioning as best it can; or beat it to death with a sledge hammer- lol

    I really should seek out some local astronomy club to bring the durn there and let the knowledgeable folks spend 10 minutes and make things right.

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    Default Re: Is this a normal collimation view Celestron 127EQ ?

    I've opted to Amazon up a laser collimator (will be here tomorrow) and will use that on my 127EQ mirrors. YouTube videos, especially those two British guys, make that method look simplest, easiest and quickest.

    Yes I know a bargain laser tool may itself need collimating, but believe it or not I already own a small roller bearing block dealie that will allow me to rotate the laser projecting on a piece of paper taped to a wall about 20' away.

    I'll still need to verify if I've got the corrector lens facing the right direction though.
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    Default Re: Is this a normal collimation view Celestron 127EQ ?

    If I remember correctly, the thicker lens element is towards the secondary.
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    Default Re: Is this a normal collimation view Celestron 127EQ ?

    It's a single lens - are you referring to having the convex side (assuming it has only one) toward the secondary rather than the concave side - again assuming that how the lens is crafted?
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    Default Re: Is this a normal collimation view Celestron 127EQ ?

    It should be a cemented doublet, if you remove it you should see a line of a thin and thick lens.
    I could be wrong of course, it has been awhile
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    Default Re: Is this a normal collimation view Celestron 127EQ ?

    I 100% trust YOUR expertise! I no doubt missed the glued double thing. I'll check it out. THANK YOU!

    You'd think by the time a guy survived to age 70, he'd be a lot smarter about such devices, but sometimes I feel like a monkey that was handed a Rubik's cube - LOL
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    Default Re: Is this a normal collimation view Celestron 127EQ ?

    I hate those things!!
    Another couple of points, when collimating the laser you only need to do maybe twice the focal length of the telescope.
    You will need to use the collimation cap to align/ center the secondary under the focuser before aligning the primary with the laser.
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    Mounts: Celestron SLT w/ pier mod & EQ-3 tripod, Celestron hypertuned CG-5 w/ tracking motor & Argo Navis, Manfrotto 028B w/ Stellarvue M2C, Manfrotto 055PRO w/ 128RC, TAL-1 HD EQ, Vixen SXP w/ HAL-130 SXG & half pier
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    Ya gotta keep this Apo/
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