Star Trails

Advice very welcome!

I post this, not in the hope of lots of 'stars' (no pun intended :)) but because night photography is not something I am very familiar with and this was the first time I have attempted star trails. Having been to two parties yesterday evening, I ought to have headed straight to bed after I had posted my blip but I made the mistake of looking outside..... I could see that the sky was clear and I realised that today I would have little chance to get my blip as the family were coming to lunch and then rain was forecast. I set my tripod up on the balcony, switched to manual and pointed the camera roughly in the right direction before clicking the shutter and leaving it to do its stuff for the next 15 minutes or so whilst I got ready for bed. I made several attempts and none of them were earth shattering but I quite like the patterns in this one. Of course, I changed the exposure etc in the RAW image - otherwise you would be seeing a much darker image (see the original jpeg version in my extras, if you are interested). However, there are lots of coloured dots - also in the original, but more difficult to see - which I assume are noise as they are too evenly spaced for sensor dust. So my question is - how can such coloured spots be avoided???

Thank you so much for everything, as always! I hope you've had a great weekend!


Ann :))