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Celestron Deluxe Tele-extender for Nexstar Telescopes
Celestron Deluxe Tele-extender for Nexstar Telescopes
Manufacturer : Celestron
Amazon Price : $61.95
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Avg. Customer Rating:3.5 of 5.0
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Product Description
Increases Schmidt-Cassegrain telescope effective focal length more than 10,000mm Fits over telescope eyepiece For use with 35mm SLR cameras T-ring not included Attachment that allows a camera to be attached to Celestron Nexstar telescopes
Product Details
  • Brand: Celestron
  • Model: 93643
  • Number of items: 1
  • Dimensions: 2.00" h x 3.00" w x 5.00" l, .40 pounds
  • Product Features
  • Increases Schmidt-Cassegrain telescope effective focal length more than 10,000mm
  • Fits over telescope eyepiece
  • For use with 35mm SLR cameras
  • T-ring not included
  • Attachment that allows a camera to be attached to Celestron Nexstar telescopes
  • Customer Reviews

    Most helpful customer reviews

    3 of 3 people found the following review helpful.
    1Returned for a more flexible/functional model
    By Eric E.
    I really wasnt impressed with this item. I bought this since it is listed in the instructions that came with my celestron edgeHD800 telescope as the accessory to buy to do eyepiece projection photography. The way it secures to the scope is really not that secure and i dont trust it to hold an expensive camera on the back of the scope. It only uses 2 screws that are supposed to tighten it to the rear of the telescope tube but the walls of the tube are not parallel, they taper slightly and i felt that this would not secure well. Metal on tapered metal with nothing to grip. I wrapped electrical tape around the tube actually to give it something to grip. I couldnt even get one of my eyepieces to focus with this. I ended up returning it and getting a varimax pro which is about doible the price but much nicer in my opinion. This may work for other model scopes. It will not hold any eyepieces that are too large, couldnt even get my explore scientific 1.25" pieces in it. A plossl fits but thats about it. You also have to use only one screw to secure your eyepiece due to the design and i did not like that at all.

    1 of 1 people found the following review helpful.
    3Three stars - it will do the job intended - ...
    By Loretta Phipps, L P
    Three stars - it will do the job intended - why 3 stars? the so-called security slot, the setscrew too large for slot, the screw hole for slot mounting drilled at angle to axis of cylinder so no matter set screw head size still would not have worked.- but since I can't imagine the rationale(?) for this slot cover anyway I just threw it and the screw away. But since it was there it should work. Rule still in effect- buy three things made in china, at least one will be defective.

    1 of 1 people found the following review helpful.
    3Would suggest a better description of the requirements particularly attachment details
    By Ricky Juarez
    Found that it only fits if I use a Barlow lens which makes the setup even higher, awkward and causes imbalance with my Celestron 127 SLT. That particular telescope does not have weights to counter balance. Would suggest a better description of the requirements particularly attachment details.

    See all 10 customer reviews...
    Editorial Reviews

    From the Manufacturer
    The Deluxe Tele-Extender for Schmidt-Cassegrain telescopes is a hollow tube that allows you to attach a camera to your telescope with an eyepiece installed. By using the Deluxe Tele-Extender in combination with an eyepiece, you can increase your instrument's effective focal length to well over 10,000mm. And this corresponds with a matching increase in image size. This technique is known as eyepiece projection photography. The following formula can be used to determine approximate effective focal length:

    EFL = telescope focal length/eyepiece focal length x DF (the distance from the center of the eyepiece to the film)

    The Deluxe Tele-Extender is used for high-power lunar, solar and planetary photography as well as for extreme terrestrial photography. It fits over the telescope’s eyepiece (even large eyepieces such as those in Celestron’s Ultima line), and connects to the visual back of the telescope. Optional counterweights will be necessary to properly balance the telescope when using the Tele-Extender.

    To use the Deluxe Tele-Extender, remove the diagonal from your telescope and insert an eyepiece directly into the visual back. Place the Tele-Extender over both the eyepiece and the visual back, then attach your 35mm SLR camera to the back of the Tele-Extender using a T-Ring. The Tele-Extender’s built-in safety device will help prevent your eyepiece from becoming accidentally dislodged.

    There are a few things to keep in mind when using this accessory. First, the image you'll see through your camera’s viewfinder will be upside-down. Secondly, due to the extremely high magnifying effect afforded by this accessory, you'll get best results by taking extra care to prevent camera and telescope vibration, to ensure accurate polar alignment, and to use under good seeing conditions.

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