Hello Lem, welcome to IIS.
Unfortunately the scope you have linked to is not really suitable for deep space photography due to it having an Alt-Az mount(Altitude-Azimuth), images shot with these suffer from something called field rotation. A half decent Equatorial Mount is needed for half decent photo's of Deep Space Object's(DSO's).
The star tracker you ask about is probably the next practical step from the star trails you have been doing, and allow you to do Widefield photography, the simplest and cheapest tracker would be a
barndoor tracker/scotch mount if you are handy with the tools, or with a bit of cash instead, something a bit better like a
Polarie or an
Astrotrac
It might be worth reading
this article about astrophotography.
Good luck and enjoy the road ahead
