Yugant - That looks good mate.. Guiding looks great, and the focus is spot on..
Yes I think a Coma corrector is worth investing in.. Newtonian reflectors really require coma correction..
As for light pollution filters.. I recently acquired a IDAS LPS P2 filter off the forums, I was amazed at how well it controlled light pollution from my home, 25km away from Brisbane CBD...
You've done well so far, The next steps are to take longer exposures and stack them together. You could essentially take say, 50~100x15sec exposures and stack those, but you will do better to take longer subs.. Even if you only go out to one or two minute exposures, you will be amazed with what you get!
Good going mate... You're on your way now!