Anthony, Back when I went to school in the '70's, my science teacher said it was to cut down the amount of light entering the telescope. My mate said it did make a difference when viewing.
OK! I have another correction (I should learn my numbers) It was actually M42 I was looking at and not M55. Who cares what I was looking at? It's all fantastic viewing.
Jen, Thanks for the welcome. I'm a night owl anyway so the hours don't worry me. According to Stellarium, Jupiter and Neptune are up now (5:23am).
All my hobbies are expensive and I'm on a pension.