This is a rewarding, varied walk with (hopefully) some excellent views. We will visit the observatory then descend well-maintained paths to the A472. After crossing the road there is a long steady ascent (100m) up a narrow lane.
At the top we will find ourselves in open country and will continue upwards to the top of Mynydd Eglwysilan. Our route then takes us across more wild open country to the top of Cefn Eglwysilan.
You can see most of the Bristol Channel from there.
Next lots of downhill on the Rhymney Valley Ridgeway Walk towards Nelson then back into Parc Penallta and quite a long steady climb back up to the car park.