Not sure how much back focus my camera has for a CC

[matt_baker]

Just received my new 130P-DS and came to realise that I have to screw the t ring directly onto the adaptor thread. No biggie until I get a coma corrector however how will I know if i have the required 55mm back focus to achieve focus?

I own a Nikon D3200

I'm currently thinking of getting a MPCC mk.3 instead of the Skywatcher one due the the reflection issues.

P.S please forgive me for being a newbie at this kind of stuff

[Ronclarke]

Can you not flock the inside of the 130PDS to stop reflections (that's what a lot of folk do!) 

 

Cheers

Ron

[rockinrome]

The camera body will have a symbol on it that shows where the focal plane is within the camera - it's like a circle split by a line [--0--].
You could also use a t-ring adapter so that the camera can be inserted similar to an eyepiece.

[michael8554]

Measure how far out the focuser is when the camera is focused.

Then rack the focuser all the way out and measure again.

The difference in the two measurements is the amount you have to play with when the CC is attached.

Michael 

 

[david_taurus83]

Hi Matt. I'm a bit confused by your question. What do you mean you need to screw the t ring onto the adapter? Doesn't the PDS have a 2 inch focuser? So if you get the MPCC it comes in a 2 inch nosepiece and M42 thread. The M42 end screws into the t ring and you insert the nosepiece end into the focuser as normal? The 55mm your talking about. Isn't that the recommended distance from the coma corrector lense to your camera sensor? The MPCC is designed so when you screw onto a Canon t ring it's already at the required 55mm. Not sure on the distance for the Nikon.