Congratulations on purchasing Apertura Collimation Knobs for the Celestron Edge HD 8 SCT, which are designed to improve your experience under the night sky by allowing for easier, tool-free collimation! Whether it’s just a quick adjustment on the fly during visual observations or a more discriminating collimation for imaging or high power use, these knobs are up to the task.
While the factory Phillips screws get the job done, they can be bothersome to adjust at night when compared to thumb screws. These solid steel Apertura Collimation Knobs make the adjustments quick, easy, and tool-free.
In this video, we'll demonstrate how to install your new Apertura Collimation Knobs.
This kit is compatible with new production Celestron 8” Edge HD Schmidt-Cassegrain Telescopes (SCTs) only and is not compatible with other models or sizes. While we have done our due diligence in ensuring that these screws will fit your telescope, it is still important to check one of your factory collimation screws against the replacements in this kit, and we will talk about this more later.
Please read all instructions and be sure that you completely understand them before removing any screws from the telescope. If you have any questions or are unsure of the procedure after reading the instructions, please contact one of our Gear Experts. We would be happy to speak with you about the installation of this product.
The only tool that you will need to perform this installation is an appropriately sized Phillips Head Screwdriver for the removal of the factory collimation screws. We’ll start by placing the telescope in a well-lit area and making sure that the front of the scope is easily accessible while being sure that the scope is secure. You can use the mount to hold the telescope for this procedure, and this is the method that we suggest!
We will want to carefully remove only one of the collimation screws with the Phillips Head screwdriver, taking extra care not to slip and scratch the corrector plate with the screwdriver. Control the tool with both hands when it is near the telescope, as to help prevent any accidental damage to the corrector plate. Do not unscrew all three screws at once; we will only remove one screw at a time. Be sure not to touch the ether two screws while one is removed. This will help to ensure that the collimation will be as close as possible after the procedure.
Once you have the first screw removed, you’ll want to match this screw against the threads of the replacement thumb screw provided in the kit. The threads should mesh together well, with an even amount of light (if any at all) being seen between the two sets of threads. If the two fasteners do not appear to have the same thread pitch and size – STOP. Do not install the thumb screw in your scope if the thread size does not match. Please contact us if this is the case and we would be happy to talk with you more about your scope and what the correct collimation screws might be for your application.
We will also want to check the thread length from the factory screw to the replacement. To do this first install a single included washer on each of the Apertura Edge HD 8 Collimation Knobs. Then, take the factory screw and the replacement screw and fully overlap the threads to make sure that the head of each fastener lines up with the end of each screw. Once we are sure that the replacement screw matches the factory Phillips head screw, we can proceed with the Installation.
Replace the removed collimation screw with the new Apertura Collimation Knob, being sure not to over tighten it. Only apply gentle pressure when initially installing the Apertura Collimation Screw. If you encounter any significant resistance whilst threading the Apertura Collimation Knob into place, stop immediately, remove the screw, check the thread for debris or damage, and retry. If you are unable to install the screw please check the replacement screw against the factory screw again.
After the first Apertura Collimation Screw has been installed, remove the next factory Phillips head screw. Remember not to turn either of the other two screws while one is removed. Repeat the process outlined above for each remaining screw.
Now that the installation of the collimation thumbscrews has been completed, we’ll need to check the collimation on the scope. It is very likely that it will need to be adjusted but with the new Apertura Collimation Screws, this should be a much simpler process now! Please do not hesitate to reach out to our support team for any assistance or guidance in using this product.
Clear Skies!
Proceed to “Collimating Your SCT”
If you have any questions or are unsure of the procedure after reading the instructions, please do not hesitate to contact one of our Gear Experts. We would be happy to speak with you about the installation of this product.
This Article was Last Updated on 07/25/2023
