Hi All,
With my new Orion Eon 110 F/6 arriving within the next week or so, the next part I want to add is a field flattener. Its a little more difficult than normal as I have the added complication of the Orion Adaptive Optics unit. (See diagram below)
The A/O unit has 48mm threads front and back and adds at least 42mm to the imaging train (plus adaptors).
Most of the flatteners seem to have about a 50 to 60mm back focus requirement which means they would pretty much have to go on the front of the QSIwsg camera because that is its internal back focus length. BUT... they also often seem to have a 2" tube on the front which means I have to add another female 2" tube holder between the Camera and the adaptive optics, that's a lot of extra length in the train.
The ideal flattener would be one with threads at both ends so I can either put it where the Spacer is between the Camera and the AO or the other option is this one:
https://www.teleskop-express.de/shop...-5-to-f-8.html
It would screw straight onto the front of the Ao unit and has a back focus distance of 109 so I guess it would be ideal for this setup. Its pretty pricey though and I have not found any reviews for it.
Also I don't know much about flatteners, wouldn't the "curvature" on each type of scopes focal plain vary? So are ideal flatteners adjustable in some way?