55mm Back Focus limitations

[SB (Chris)]

Hi everyone
With rotation assistants now becoming more common I’m realising that the 55mm back focus standard is becoming a bottleneck as it wont be long before electronic rotators will released and automated into software I’d imagine. But how would they fit into an imaging train with an OAG and filter wheel taking up the bulk of the 55mm?

Does this mean there will be a migration to Petzval refractors that allow longer backfocus?

Chris

[Joshua Bunn (Joshua)]

Hi Chris,

The place for the rotator would be before the reducer/corrector, and therefore not consuming any of that 55mm backfocus.
Regards Josh.

[SB (Chris)]

Originally Posted by Joshua Bunn

Hi Chris,

The place for the rotator would be before the reducer/corrector, and therefore not consuming any of that 55mm backfocus.
Regards Josh.

Hi Josh
Thanks. I have a manual rotator at that location on the Esprit. It works well with the new ASIAIR rotation assistant. It would be so good if is this was automated. However I think that it’s unlikely a company would create an automated rotator for each scope model and more likely to release a generic rotator to fit in the backfocus part of the the imaging train.

The automated process would involve taking shots, plate solving, comparing position, repeating etc then recalibrating the guiding if using an OAG.

Just having this new manual rotation in ASIAIR is fantastic - hardly any cropping when using a OSC then shooting same target with Mono narrowband (same size sensor) and combining the stacks.

Chris