Hello I recently purchased a new celestron telescope and set it up last night to use for the first time. I live in UK, around 8/9pm-ish I took my telescope outside to view Venus in the western sky as it was v bright, perfect opportunity. After finding Venus and increasing the focus I realised that there was something like a large black circle in the centre of the bright blue/white ring of light. Before focussing, it appeared to be just v bright light. I am wondering if anyone can explain to me why this black circle appeared on / in front of Venus. I thought it looked like a moon, which is obviously incorrect but it looked that way. Is it possibly sulphuric clouds of Venus absorbing light? Any information/help is much appreciated happy observing, all!