Componon-S 150mm mounting thread - 42mm

[walter23]

For anybody interested (if anything for archival purposes, in case someone in the future searches the site) I learned this week that the mounting thread on the older componon-S 150mm (M42x.75, or 42mm thread) is actually the same as the photographic / astronomical T2 mount. You can find T2 locking rings or T2 retaining rings at astronomy supply stores for much less than the cost of a retaining ring ($40 from B&H, more for a custom machine job).

For example, here (http://www.alpineastro.com/eyepiece_adapters/eyepiece_adapters.htm#Threaded%20Couplings).

[Nick_3536]

The last 150mm lens I bought was about $40 including a ring. In todays market it makes more sense to just buy a replacement then fight a common lens.

[Donald Qualls]

And the last 150 mm *I* bought was $180, including shutter and retaining ring.

I think it's useful to know that those lenses (is that the lens in a barrel, or in some particular shutter?) use the same thread as a T mount (especially since I have a couple T rings already on hand, acquired for use with my telescope).

And if that's the case for a Componon-S, it might also apply to my 135/5.6 Vivitar VHE, or to my 105/5.6 Vega with internal color filtration.

[Gregory Jones]

Does that mean I can screw my Componon-S 150 into a T-mount adapter, and then screw the adapter into an Omega D2 lens disk and the setup will actually work? The thickness of the adapter won't cause focus problems or vignetting? Much as I love SK Grimes, I'd prefer a $10 adapter to a $60 custom-drilled disc.