SW SKYMAX 150 thread size

[focaldepth]

Hi all,

This a frequently asked and answered question on SGL and other sites but I still can't find the answer.

I have a SW Skymax 150 and want to fit a Borg helical focuser. The Skymax has had several thread sizes over the years, mainly a 2" SCT and a Mak thread of M44.5mm.

However mine has a 66mm diameter thread size onto which screws the 2" eyepiece tube, used by the diagonal.

The 66mm thread may be removable but will need a very big hammer to loosen it.

 

I do not know the manufacture date of the scope as I bought it second hand.

 

Does anyone know what this thread size is or if it can be removed with enough force?

It dose have holes for a pin wrench, just too big for any I have at the moment.

 

[Avocette]

The 66mm thread seems to have been unique to the SkyMax until in recent years the SCT thread replaced it. I don't think you should attempt to budge it - better to get hold of one of the special adapters to fit this thread and convert to SCT, at around £40 a unit last time I asked. 

[focaldepth]

1 hour ago, Avocette said:

better to get hold of one of the special adapters to fit this thread and convert to SCT, at around £40

Great where from?

[triton1]

Flo have them at the top of the page.Not in stock apparently.

[focaldepth]

Thanks but I had already tried FLO. Their's is the 44.5mm one and they don't stock it. I need to know what the 66mm thread size is called, or a stockist of a 66mm version.

I am happy to buy one or get one made but I need to know what size it is as it aproximatley 66mm. I can measure the outer diameter and the pitch but I don't know what nominal size it should be. The pitch is about 1mm, I'll search for my thread gauges to get a better guess. For now I assume M66x1mm.

Any one else encounterd one before?