Losmandy rail where a Vixen was?!

[deanm (Dean)]

I have a C11 XLT: can I replace the Vixen dovetail with a wider Losmandy?

I'm not keen on OTA drilling!

Dean

[mithrandir (Andrew)]

Originally Posted by deanm

I have a C11 XLT: can I replace the Vixen dovetail with a wider Losmandy?

I'm not keen on OTA drilling!

Dean, you just need the bar, a set of blocks and cap screws. They go straight into the holes the Vixen style bar uses. This is Bintel's listing but it doesn't say if the screws are included. The Celestron ones from the old bar may not be long enough.

There are also a set of holes in the other side of the OTA for another bar. The short screws in the holes are just to keep them clean. They don't hold anything in place.

[deanm (Dean)]

Many thanks indeed, Andrew - I wasn't sure at all about the occupied holes : youve cleared this up!

Dean

[g__day (Matthew)]

My C9.25 CF has an interesting arrangement of screws. From memory the upper and lower body had one screw in the front (to mate rails top or bottom) and a choice of four holes at the rear (two always plugged). This allows one to set up for wide or thin rails.

As stated the Losmandy D rails mate really well and are very secure.

I do recall having to drive all over Sydney, eventually out to Parramatta to the third and largest specialty screw stockist I could find. The screws used where very unusual - American gun sight screws I was informed. They had a very unusual pitch and thread width (certainly not any normal metric or imperial screw). Normally I thought you just matched length and size - but oh no - I could match that, plus pitch 8 / 32, but the thread width was distinctly unusual.

Check closely on the screws you may need. If not included and of the right length you may have to search long and hard to find a stockist.

Oh and cut them to the right size - make sure a re-fitted screw won't hit the mirror when you move it in or out or you might be able to damage your main mirror! I cut mine to lenght by measuring them first, then you screw a bolt or two one and use these bolts to hold them firm in a vise; then use a hack saw to remove the excess length. Then you lightly file the ends, take them out of the vise and finally screw the bolt on and off twenty or thirty times until the end is smooth and it goes on and off with no roughness.

[mithrandir (Andrew)]

Originally Posted by g__day

I do recall having to drive all over Sydney, eventually out to Parramatta to the third and largest specialty screw stockist I could find. The screws used where very unusual - American gun sight screws I was informed. They had a very unusual pitch and thread width (certainly not any normal metric or imperial screw). Normally I thought you just matched length and size - but oh no - I could match that, plus pitch 8 / 32, but the thread width was distinctly unusual.

Matt, Bintel had the right screws, pitch and length, to attach a Losmandy bar to my C8. I forget if they threw them in or I had to pay for them. There's a place just down the road from home that probably has them too.
I have bars on both sides of the OTA - Losmandy to the mount and the Orion one with the guide scope package on the other.

[Merlin66 (Ken)]

Dean,
I got a replacement Losmandy dovetail for my C11, complete with screws etc. No additional holes, just use the one's already there.

[deanm (Dean)]

Many thanks Ken & others - I know where I'm going!

Dean