15.02.2022 T-S collet-style 2"-1.25" eyepiece adapter.

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 Tuesday 15th grey and breezy.

 The new eyepiece adapter turned up in the post. Finally I have an eyepiece clamp which will work on the grossly undersized, Orion Cheshire collimation eyepiece. 

 I have tried several 1.25" fittings with bronze bands and three compression screws. The Orion barrel was always far too small to grip and align with the focuser. 

 The new clamp uses a large knurled outer ring to squeeze the clamping ring evenly all round. Moreover it has no projecting thumbscrews to prevent the fitting entering a 2" extension or focuser.

 These images are absolutely awful! I took them in the darkened dome with flash. The SW wind was to strong to open the dome.

 I shall take better pictures in daylight tomorrow.

 

 

 

16th 40F, overcast and raining.

Due to the weather I took these pictures on a southern windowsill with flash. 

The 2" to 1.25" adapter is a sturdy lump of solid metal. Its 2" fitting provides new options for a firmer hold on cameras, binoviewers and solar wedges.

 

 The underside of the adapter. 2" plug fit with M48 filter thread. The 1.25" internal eyepiece fitting should be self centering and is remarkably secure. No damage to sensitive surfaces either. I haven't yet tried it with an undercut eyepiece.

 

 

 

 The bronze clamping ring is split and has a small screw to prevent rotation. At a second attempt the outer, knurled ring came off without effort. I presume it depends on the compression adjustment prior to removal. Or, the tension on the large "washer?"

I sense the device is using differential threads and pins to achieve its purpose. Not unlike my short range, helical focuser.  Putting it back together was a puzzle at first. 

The large "washer" is only threaded internally. Smooth on its outer rim. It is not captive under the knurled ring but fits inside it on the upper surface. It is threaded onto the smaller hub diameter, by finger friction and is non-rotating. The knurled ring is threaded onto the larger diameter of the inner hub. Factory assemblers might have used a rubber, friction cup to tension the large washer.

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