Omega Centauri is not visible from the UK - M13 is in Hercules and is rising nicely in the east at this time of year. It's good and bright and globular clusters like this show up pretty well through light pollution and can cope with high magnifications (unlike galaxies, where there's not enough contrast with the background darkness).
At this time of year I'd say M13, M92 (another globular cluster in hercules), M81 and M82 (galaxies in Ursa Major - at low magnification it's cool to get both of them in the same field of view); if you have a good clear southern horizon it may be worth having a go at some of the nebulae and clusters in Sagittarius. Can't remember the M numbers but I think 15, 16, 17 and 22 are down there. Also the wild duck cluster in Scutum is a good dense one - I think that may be M11.
As for guides, I reckon the best one around is "Turn Left at Orion" by Guy Consolmagno (the keeper of the Pope's collection of meteorites) and some other guy. It shows things season by season and tells you how to find them (well, your scope should do that for you) and a bit about them, and had drawings showing what you should expect them to look like, so you won't be expecting Hubble-quality colour images.
Omega Centauri is not visible from the UK - M13 is in Hercules and is rising nicely in the east at this time of year. It's good and bright and globular clusters like this show up pretty well through light pollution and can cope with high magnifications (unlike galaxies, where there's not enough contrast with the background darkness).
At this time of year I'd say M13, M92 (another globular cluster in hercules), M81 and M82 (galaxies in Ursa Major - at low magnification it's cool to get both of them in the same field of view); if you have a good clear southern horizon it may be worth having a go at some of the nebulae and clusters in Sagittarius. Can't remember the M numbers but I think 15, 16, 17 and 22 are down there. Also the wild duck cluster in Scutum is a good dense one - I think that may be M11.
As for guides, I reckon the best one around is "Turn Left at Orion" by Guy Consolmagno (the keeper of the Pope's collection of meteorites) and some other guy. It shows things season by season and tells you how to find them (well, your scope should do that for you) and a bit about them, and had drawings showing what you should expect them to look like, so you won't be expecting Hubble-quality colour images.