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  1. #11
    Gadget63's Avatar
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    Bob maybe it's my eyes or something else wrong with me, but I tried the big doughnut alignment and never had much success. I'd get the alignment successful statement but when I'd slew to any object, I'd be lucky if it were even near the eyepiece. Once I bought the illuminated recticle eyepiece, my alignments have always been precise and no matter what I slew to during the evening, it will always either be dead center, or very close to it.
    Celestron NexStar 8 SE, Heavy Duty EQ Wedge, Celestron 8mm-24mm zoom eyepiece, Celestron eyepiece/filter accessory kit, Celestron power tank, Telrad, Nikon D80 DSLR camera with T-adapter and focal reducer, Celestron 80mm guide scope, Celestron Neximage, Celestron Nexguide, Celestron CGEM-DX EQ mount!

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  2. #12
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    Quote Originally Posted by Joe Lalumia View Post
    For alignments -- Yes. For collimation -- no.
    I want to disagree with this in the most subtle way.

    If you are not used to placing an object (star) at the precise center of a big FoV then the cross hair EP will help on this. And you cannot correctly collimate any scope unless the star is at the precise center of the FoV.

    However, I fuly agree that the final fine collimation (using absurd magnification) looking at how the diffraction pattern collapses towards focus is the correct way to achieve precise collimation. No cross hair EP is required for this (nor are cross hair PEs tipically high poer EPs).

  3. #13
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    Don,
    I have a Meade Astrometric reticle. It's very useful if you want to calculate diameters of objects and offsets. Apart from that, the lower section is very useful for guiding (which I don't do yet). The middle scale is what I use to calculate Polaris's offset from the CP. I just center Polaris in the scale..and then adjust the mount to offset Polaris the correct amount (40-41 mins) from the CP to get a close Polar Align. If you have a Polar Scope, this is not necessary, just use the Polar Scope. The other thing the center scale is useful for is for drift alignment, but you can do the same with any double line illuminated reticle EP. For those who don't know what the Meade EP looks like, here's a pic:



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  5. #14
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    Default Centering

    Quote Originally Posted by Bob327 View Post
    Joe is correct an illuminated eyepiece will be of no help when collimating and to be honest not much of a help (if any) when aligning...just defocusing the star so it appears like a big fat donut in the eyepiece makes centering a star a piece of cake...

    Compare centering a pancake on a dinner plate against centering a grape on the same plate...

    Bob G.
    Nice tip! Thanks!

  6. #15
    Joe Lalumia's Avatar
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    The center of the field collimation is just not true. All you are trying to do by re-centering the star during collimation is to place it in the center portion of the eyepiece where any eyepiece aberrations will not affect the collimation.

    Again-- you do not need an illuminated eyepiece for collimation only for alignment (some people use them some don't) and or for drift alignment for astro-photography.

    Just bring the star back toward the center away from the edges of the eyepiece.


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  7. #16
    Bob327's Avatar
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    Quote Originally Posted by Gadget63 View Post
    Bob maybe it's my eyes or something else wrong with me, but I tried the big doughnut alignment and never had much success. I'd get the alignment successful statement but when I'd slew to any object, I'd be lucky if it were even near the eyepiece. Once I bought the illuminated recticle eyepiece, my alignments have always been precise and no matter what I slew to during the evening, it will always either be dead center, or very close to it.
    You have an impressive list of equipment..But I am assuming you have problems with the 8SE when on its OEM Alt/Azm mount...

    I have to ask you how it is balanced on the dovetail, what your goto approaches are set at, and what EXACTLY are the last TWO individual direction buttons you ALWAYS..repeat ALWAYS touch LAST ...

    The right button should always be hit last... but depending on the other stuff (balance approach settings etc) you may have to touch either the Up or Down button to center the star in Altitude before you hit the right button ... it all has to do with the inherent slop in the spur gears ...Backlash settings can only remove MOST of the slop

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  8. #17
    Gadget63's Avatar
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    Bob, thanks for the compliment on my equipment! I am slowly but steadily upgrading since I just love the photography aspect of this hobby. As for your questions, yes it's only when I use the alt/az mount.
    I always make the right and the down buttons the last ones i touch when aligning. If I miss the mark I start again but always right and down last.
    balance on the dovetail was always a little bit rear heavy. i remember reading somewhere to have a little weight towards the back.
    A always had a major problem with the mount mysteriously rebooting and losing my alignment if i tried to adjust the backlash or goto settings on the mount. I had updated the firmware for the motor and the HC but upon reading here, I downgraded the HC to the previous version prior to 4.20 and still had the same problems. When I explained all this to tech support at Celestron they gave me an RMA to send the mount back since it's under warranty. I admit since getting my new mount I will only be using the alt/az when I travel on vacations or if I am not setting up for photography.
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