Focuser Draw Tube Lengths

[scarp15]

Hi, myself and another SGL member are currently investigating upgrading the stock focuser on our 300p flextubes.

This has led to looking into moonlite focusers, as the converstion kit provides a problem free installation fit.

We would like to clarify the variations on draw tube lengths, as Moonlite focusers provide a range from between 70mm to 38mm of travel? The stock Skywatcher focuser is I believe approx 75mm. For visual the 50mm is recommended, however what are the implications for various lengths such as - will the focuser require to be relocated, and how if at all will this affect the focus.

Thanks

[Merlin66]

The prime focus position won't change....you may need a couple of extension tubes to get the maximum coverage of eyepieces...

[scarp15]

Hi Merlin66, Thanks for the info, which eyepieces - high power / low power, might benefit more with the addition of an extenion tube?

[Merlin66]

I can't honestly answer that!

If I assume you will have 55-60mm back focus made available for a DSLR/ CCD etc and the travel on the new focuser is roughly 30mm, you'll need probably a 25mm and/ or a 40mm spacer to allow your eyepieces to come to focus.

Hope this makes some sense.....