Does anyone know the actual specification for the threads for 2" and 1.25" EP filters?
I measure the 2" filter thread at 48mm (assumed*) x 0.6mm pitch and the 1.25" filter thread at 28.4mm x 0.6mm pitch. 28.4mm is an odd metric size, but it is very close to 1 1/8" which makes sense, but 0.6mm equates to 42.333 threads per inch, which is a strange imperial size
. Maybe it's 42 TPI? 0.6mm thread gauge fits but it could be a better fit...
*ID measured at 47.5mm, but I know 2" filters are often talked about as 48mm. Unfortunately, I don't have a 2" filter to measure the OD of the external thread.
The reason is I want to make an adapter so I can screw a 1.25" extension tube into the back of my 1.25" to 2" EP adapter... this will allow me to push my Staranalyser up the baffle tube of my C11 to maximise dispersion while maintaining focus
. At least that's the plan
...
Al.