Hi Ian,
The light pollution from a big city affects the whole visible light spectrum. Long exposure astrophotography is not possible with a bare “naked” sensor, it takes a few seconds to get a full white rectangle. Faint objects get completely washed out.
One of the best counter measures are the dual-narrowband filters. They block all the spectrum but two very specific bands tuned for the emission lines of Hydrogen Alpha (Ha) and Oxygen iii (Oiii), enabling the possibility of shooting those nebulæ from the City. That's how most of the urban astrophotography gets done.
Unfortunately, even with such filter, regular consumer cameras struggle to get most of the Ha signal due to an embedded filter they all have in front of the sensor that blocks part of the deep reds. It's not impossible by any means but it takes a lot more effort compared with a dedicated astro-camera.
Here's one shot with my Sony camera and a Ha/Oiii filter:
📷 1000374551.png
As I said on the previous post, all this is a lot to digest. It takes a lot of time, failures, frustration… and then it pays off. You need to enjoy the challenge and the journey.
Regarding the installation of the filter, it definitely needs to sit between the telescope and the camera. I'd recommend reaching out to other 71f users to see if you need a filter drawer or it can be directly attached to the back of the scope. I still recommend doing a step at a time to learn how all the pieces fit together.