Narrowband filter use with an OAG

[justanothermidlifecrisis]

Hi,

I'm looking to shoot deep sky objects with narrowband filters.
My setup is ...

Redcat 51
ASI 183 MM 
ZWO OAG
ZAO EFW
ASI 120 MM mini

I control this setup with the ASI AIR Pro

The imagining train is SCOPE > OAG > EFW > Main Camera & the guide camera bypasses the EFW (& filters) as it's seated in the OAG

What I've come to realise is that the use of the OAG is a pain in the backside when changing filters.
When the filter change occurs  the main lens needs to be refocused but in the act of refocusing the main camera it throws the guide camera out of focus. Queue fiddling messing around with guide cam which is time consuming.

I think I've resigned myself to the facrt that I'm going to have to get a seperate guide scope but I'm also interested in people's experiences of using the ZWO EAF with ASIAIR Pro when using different filters.

Does it work well if I were to shoot a sequence of SHO Lights changing filters as I went.
Obviously I need to get more manually involved when shooting the calibration images but I'm hoping that some degree of automation can occur for the lights.

Any feedback/observations are gratefully received.

I've attached a recent image I collected of the North American Nebula using my Ha filter.
It's been stacked and stretched with no other processing.

Warm regards
Phil

[wimvb]

The guide camera doesn’t need perfect focus. In fact, some argue that a tiny amount of defocus is beneficial. Unless there is a large difference between focus positions for the filters, you may be ok. You can set the guide camera focus between the extreme focus positions for your filters

[ollypenrice]

If it doesn't work I'd just use a guidescope. An OAG with a small refractor strikes me as being a solution looking for a problem and creating one. But do you have a guiding problem if you don't refocus the guide cam? If you go for a mid-position compromise?

Olly