Quote:
Originally Posted by E_ri_k
Thanks Allan. Yeah that all makes sense. I was using the formula of the AP website to calculate the distances. The reducers FL-distance to sensor/reducers FL, so (305-D)/305. My understanding was that 101mm is the optimum measurement, to give a .67x reduction, but the greater the distance, the greater the reduction? Or did I understand that wrong 
I am am planning on using the reducer in front of my ONAG. So I need to get some adapters and threads and things, because everything is a different thread of coarse  but I'll be able to make it 101mm pretty easily I think.....
So by your picture, I'm guessing the camera goes on the end of your extensions?
Erik |
Eric
Read David Cortners website about the ccdt67 and spacing as he has got it down to f5 with different spacing and still gets round stars
http://www.davidcortner.com/slowblog/20110815c.php
You are correct in that the camera goes on the end of the T spacers. If I use the Qhy then the setup as shown is used as is but if I use the QSI then I remove the 30mm spacer and I'm set to go.
Allan