In order to take a photo through your SCT you need an SCT-to-T adaptor. A one that is often used is Celestron’s T-adaptor for Schmidt Cassegrains (their 93633-A). However currently there is a shortage of some accessories (due to Covid19) including this useful and popular item.
An alternative to the Celestron accessory is Baader’s Universal Photo-T adaptor, which is much more than just an “ordinary” SCT-to-T adaptor. The unit comprises two separate Baader components:
- 2958500A: This adaptor that allows you to convert the Celestron NexStar4, C90 and Meade ETX rear male thread into 2″ SCT male thread so you can use SCT-threaded accessories with these telescopes. This part also includes an internal thread so you can screw in and use a 1¼“ filter.
- 2958500B: This is an ultrashort 7mm optical path length adaptor which converts the 2” SC male thread of the above part to T-2 male thread to allow e.g. a camera to be attached to a Celestron NexStar4, C90 or Meade ETX telescope. This part can of course be used on its own on the rear of an SCT/HD telescope to attach a female T-threaded accessory.
Mating the above two items together forms the Baader Universal 2-in-1 combined T-2 Photo Adaptor MAK & SCT telescope with 1.25″ Filter Holder.