F 6.3 or F 3.3?

What is better meade f6.3 or f3.3 focal reducer for a 6" f7 scope.It is for my meade DSI(I am asuming that it screws into imager)

Also on another matter, does anyone know what is the name of the mount on the celestron C150 HD scope, I am trying to get drive motors.I think it is a CG-4/EQ3 mount.

Brian --

I'm not sure either one is going to be what you want. They both screw onto SCT threads, not filter threads, so I don't think they'll attach to the DSI (it's a 1.25" eyepiece barrel, right?).

They're also made to flatten the field of an SCT, so I don't know how well they'd work for a Newt or refractor (at least a 6" f/7 certainly doesn't sound like an SCT).

A company called Atik makes a 0.5 focal reducer (which would reduce your f/7 to f/3.5) that screws into filter threads. It's probably more along the lines of what you're looking for (and cheaper). I think Ian King Imaging sells them.

-- Jeff.

Hi Brian,
Jeff is right about the sct threads, to use these you need sct adapters.
Also the f3.3 is quite a difficulty piece of gear to use apparently, it comes with spacers, these are needed in order to achieve focus. It'll probasbily work on a DSI but not with film or DSLRs are you get serious vignetting.
also a F7 scope would become a F2.1 system, I dont know if it would hold up optically.

I guess I should have told you what I wanted to do, I am still learning so I am getting things wrong sometimes. :oops:
I have a meade DSI and I want to image a wider field of view.

Jeff a 0.5 focal reducer sounds like what I need alright. :idea:

Thanks guys

Jeff I looked up Ian King Imaging www.iankingimaging.com/show_products.php?category=17 and I found what you were on about (second product down).It said that newtonians would not be able to achieve focus with it, any suggestions :