LP Filters, EQ2 RA Drive Motors, Field Flatteners, Sky-watcher Star Adventurer

[Leon-Fleet]

So I've got my first Scope, a second hand Konuspaace 114mm Newtonian 500mm, and an Eq2 mount to go with my Nikon D90, and now I'm after some accessories to finish off the package. I've also got the Sky-Watcher Star Adventurer Pro Astro Photo Bundle and I am trying to figure out the best arrangement of it all. 

I've been looking at Light pollution filters, Ideally clip in but they seem to be out of my budget for now. I'm not sure where to find screw-on filters that will attach to a T-ring or camera while my camera is attached to the scope. hope I'm making sense, I don't know the correct words. where can I buy these online? 

I'm also considering getting a Skywatcher RA Single Axis Economy Motor Drive. however I've heard that these create a wobble so might not be suitable for imaging, with long exposures?  Has anyone any experience using these while Imaging? Ideally, I'd use the SA to do the tracking but don't know if it can hold the camera and scope? again any advice would be great! 

And finally Filed Flatteners, I'm confused as to where these go, when the camera is attached to the scope...  are they necessary or can the Image be flattened in processing?  

thanks in advance! 

[Cornelius Varley]

Before purchasing any more equipment, especially the field flattener as this will probably not fit your telescope, check as to whether your telescope will reach focus with the camera, most budget telescope don't without some modifications ( ie moving the primary mirror closer to the secondary or using a barlow lens to push the point of focus outwards).

[Leon-Fleet]

oh! thanks, Peter, that wasn't something I had thought would be a problem. 

cheers