DSLR to a LightBridge
Someone asked: “Has anyone had difficulty focusing a DSLR to a LightBridge? I bought the appropriate adapters but cannot focus on any subject. It would seem that the LightBridge focuser extends too far away from the secondary. It seems the obvious answer is to install a focuser with less length. ”
Yesterday I was also trying to focus my DSLR Canon EOS Rebel XTi (EOS 450d) through my Meade Lightbridge 16″, but it was not possible. I haven’t still bought any T-adapter, because I was not sure it could reach the focus. Indeed it doesn’t reach it even without any adapter.
Maybe changing the focuser to a zero profile one could work. Or maybe not.
There is a trick to find out where the focal plane is exactly. When seeing the Moon, remove any eyepiece from the focuser and project the light into a cardboard perpendicular to the focuser axis. When the Moon gets clear and focused, there it is exactly located the focal plane at prime focus.
Knowing the distance from the CCD camera to the T-adapter it is possible to find out if a low profile focuser could reach the focus for prime focus astrophotography.
Computer Physics Lab 
2009/06/19 at 12:30 am
I have gotten it to work, I use a 2x. Barlow and for some optical craziness it comes to focus.
2009/09/17 at 12:35 pm
I’ve tried with a 1 1/4′ 2x barlow but it didn’t work (mine is a 12′). Do you mean a 2 inch lens? Someone suggested a 2 inch to me but I haven’t tried that yet.
2009/06/19 at 1:11 am
Good to know it. I will try it. Thanks!
2013/11/17 at 2:20 pm
Hi, I have the 16″ and with a 2x barlow, it focuses correctly (at twice the zoom, so the moon is no longer places in a single frame of my DSLR). I assume that If I use a 0.63x focal reducer it won’t do the trick, but I still haven’t tried it.