CCD Spacing question

[photosinferno]

Hi All,
Long shot I know but does any one know by practical experience - or can point me in the right direction - of the 'Spacer' distance for the William Optics Field Flattener 3 from the CCD/Sensor plane?
The schematics from WO seem to indicate 56mm - I just want to confirm that is what people have practically experienced :shrug:
The CCD I'm going to be using has 13mm of back focus inbuilt.


Many thanks
John

[graham.hobart]

Hi, I believe that is the same spacing that the WO IV and the hutech FR have i.e 56mm so in my (limited experience) you are correct- 56mm minus your CCD backfocus (taking into account any connectors or filters) is what you are left with to space.
I use approx 30mm spacers on my OSC CC with a reducer/flattener.
I don't think the spacing on flatteners is as critical as on reducers but I may be wrong.
Cheers
Graham

[photosinferno]

Thanks Graham,
That confirms what I thought- at least I can start in the right 'ball-park' :)

Many :thanx:
John