Most Celestron finders are the same as Sky-Watcher, and have 11 fine threads cut into the rear of the finder tube.
However some are different and we now have a separate adapter for those Celestron finders with 8 coarser (1mm) rear finder threads. Simply remove the eyepiece and holder to check.

[SPC900 / SPC800 to Sky-Watcher and GSO to C & T adapters are also available ]

Please contact us prior to purchase if you are unsure

Focus is achieved in the same way as using the finder visually, by screwing the objective in and out, then locking final position with the knurled locking ring. It’s best if focusing leaves star images slightly enlarged, as this gives auto guiding software a better chance of accurately determining the image centroid.

Our tests have confirmed online calculations that guiding is successful to the limits of what seeing allows. Because of the light weight, stability is excellent as long as screws are tightened properly and cables secured to prevent drag. I only recommend off axis guiding for scopes that are found to be prone to mirror movement or significant differential flexure over the course of your usual exposure. Even then many large SCT owners have been able to take 10 minute exposures or more without visible issues, so its always worth trying for the ease of use and low cost.

Using the finder as a guide-scope reduces the weight and complexity of your imaging setup, and the wide field of view guarantees finding suitably bright guide stars in every part of the sky.

The post Sky-Watcher & Clones to C Mount Adapter for Right Angled Finders appeared first on Modern Astronomy.