heath if your scope only weighs 5kg you could get away with a good fluid head - while in the US i bought one rated for 8kg, at the moment bhphotovideo.com have them for 99.95 - a great price -
http://www.bhphotovideo.com/c/produc...ford_FM18.html not a manfrotto but 80% the quality -has the counter balance tensioning spring to manage a heavy load - i ahve had big 25x100 binos on it at 5kg & handled them withnout slipage