TPO 2" SCT Focuser - Crayford Dual Speed

This is an excellent focuser and as usual, OPT did a great job helping me and making sure the item was expedited.

Just tried this focuser on the back of my C9.25. It works great - solid attachment - and rotatable, what a bonus not having to adjust the diagonal all the time. I put a 2 Explore Scientific Diagonal in the focuser and it works very smoothly. A really nice piece of equipment! Well done OPT.

For years I struggled with focusing my SCT, particularly when photographing the moon and planets. With this focuser it’s become much easier to achieve proper focus. Focusing action is very smooth and accurate and load capacity seems adequate for a heavy dslr. Even when tension is increased to hold the camera it’s very easy and smooth to achieve focus. On the other hand, this thing is heavy!! And being long also displaces the CG further back making balancing slightly more complicated (I had to place a counter weight at the front of the tube). Also, you need to be careful with the screws that allow rotation of the body as they can be slightly loose and will let the focuser fall if not secured with the thumbscrew. But once you get used to its workings I found it to be a bit of a blessing. You can detach the ring from the focuser, screw it onto the rear cell and then reattach the focuser. It’s much easier than rotating the whole focuser onto the rear cell. Just remember to tighten the thumbscrew!! All in all I’m exceedingly happy with this focuser

I recently bought a used Celestron C8 which from the documentation that came with it dates the scope from 1984. The optics on this scope are good but I was constantly having issues with fine focus. This scope was modified in 1984 with a Tuthill Star Trap tracking module (which still works very well) and an updated focuser. I had been reading about issues with older C8’s and mirror focus issues and everyone seemed to feel that a secondary Crayford type of focuser was the solution. I saw this TPO Crayford focuser and read reviews on OPT. It looked like the way to go, and indeed it was. Visual viewing was markedly improved much to my surprise. What I thought was in focus I now realize was not as sharp as it could be. While we have poor seeing conditions in the inland empire area of southern CA, this focuser was exactly what this telescope need. A huge improvement. OPT of course is the best at customer service. Thank you OPTcorp

This is a well built unit that is also big and heavy. The quality of the movements, the locking devices and markings are all good but the most important thing to know is that if you have a small SCT such as the Nexstar SE4 or SE5, do not purchase this item as it will not fit on small OTAs. The available space between the focus knob for the primary mirror and the SCT threads on the back of the OTA is to narrow, this prevents the focuser from reaching the threads without the use of an additional extension tube. If you are able to find an extension then be sure to calculate your back focus or you may create another problem.

Most of our research instruments are RC telescopes, but we do have one original C-14 that we use for a number of different projects. Likewise, we use several different instruments of varying weight from small and large format CCD cameras to heavy CCD spectrographs on it depending on our project and research needs. This TPO 2” focuser handles the weight of all of them without any instrument sag. The fine movement allows for quick and easy refining of the focus. Moreover, it allows me to get the rough focus using the C-14’s focus knob and then lock the primary in place so there’s zero image shift across the sky. Remainder of the focus is done with the TPO SCT Focuser. Plenty of adjustments to make the setup solid. Excellently designed. If I were forced to purchase another SCT, this gem of a focuser would be purchased with it.