I am trying to get a good as possible, my back focus for my camera/flattener.
I want to do some more testing with spacers that are less than the 5mm metal M48 spacers. I have purchased a set of very small spacers that include 3mm, 2mm, 1mm, and .5mm. Of course these are too thin to have screw threading but just get put between the metal M48 spacers. The problem is my telescope can accommodate exactly the metal spacer opening. When I add the <3mm spacers I have purchased, I am not able to slide the flattener/M48 tubes into my telescope because the <3mm spacers are oversized.
I can add these smaller spacers on the side where the Metal M48 screws into the camera so it does not have to be inserted into the telescope but it takes way from the threading from camera to metal M48 tubes. I'll go 1mm but no more as there won't be as much thread available to screw into the camera.
Is there any source to get small spacers that do not extend past the M48 metal tubing?
Thanks for any help.