Alstar Astronomical 2 inch M48-extension Tube Kit for Cameras and eyepieces - Length 5mm 10mm 20mm 30mm - M48x0.75 on Both Sides

I'm fairly new at astrophotography and knowing I had to have a certain mm from scope to camera is not always an easy job. I have bought two of these sets so far for my camera setup and they work great. One i use for 55mm backfocus and the 2nd for a 105mm backfocus and between the 2 kits i have just the right extension sizes. I highly recommend this kit to any astrophotographer.

All I needed was the skinniest one but they all look like they will work just fine.

For items like this, it's all about well-machined threads, and these are good. Very pleased.

Because the eye-pieces I have are different lengths, I needed to be able to adjust the distance between the telescope and camera so the eye-pieces are all the same distance from the sensor. These thread directly onto the "T-ring" adapter and allow me to change the distance in small increments to achieve optimum focus.

We used the Alstar 48mm extension set to increase the reduction of our telescope compressor by almost a full f-stop.

Great to have multiple spacers available when setting up rigs. They’ll come in handy.

Worked perfectly to get the right distance for my coma corrector.

Does just what it says. Good quality machining, no problems!

These are well-finished and reasonably sturdy extension tube segments. They thread smoothly and securely onto each other, and to other M48x0.75 thread items such as 2" astro filters. No burs or marring. Nice matte black finish inside and out, low reflectivity.