8 inch sct focal reducer questions
Posted 06 January 2013 - 01:09 AM
The last question I have is regarding guidescopes. Right now I have the celestron 80 guide scope and have it piggybacked to the top of the c8 (or at least I will once I decide on a guide camera). What is this that I read about flexation and needing to lock the mirror. Is the celestron 80 to big for a c8 and should I go with he orion 80? (I can still return the celestron)
Posted 06 January 2013 - 09:42 AM
With any focal reducer you will need to maintain a certain amount of spacing behind the reducer. If you are talking about the f6.3 SCT reducer/corrector it will require about 110mm to achieve the full .63x reduction factor. You can reduce the spacing down to about 75mm or so (with the corresponding lowering of the reduction factor - to about .8x or so).
If you put the focuser between that reducer and the eyepiece you may have too much spacing.
If you put the reducer on after the focuser you'll need both 2" barrel to SCT adapter and spacers (or a diagonal) but you will also have to watch the amount of focus travel you still have. In some configurations you may find that some eyepieces won't come to focus behind the reducer if the reducer is moved back from it's position right against the rear cell.
Posted 06 January 2013 - 10:08 AM
Posted 06 January 2013 - 10:47 AM
Posted 06 January 2013 - 11:25 AM