Hello from England

[Thedirtycat]

Hello. Got my first DSLR a couple of weeks ago. Over the last few years I've seen some amazing pictures and love some long exposure pictures so a few times used my old canon camera to do some long exposures that were blurry as I had no tripod.
Recently I was outside watching a meteor shower and though it would be amazing to take a picture of the sky. I knew nothing about setting but realised I needed to put the iso to the max setting of 1600 and longest exposure time of 15 seconds to actually see any detail but it looked really bad (huge amount of noise).
So as my girlfriend was over and we were going lots of places I though I'll just go for it and get something good and went for the nikon d5300 as it was fairly modern, quite low noise and high iso and decided the flip screen might be useful for astrophotography.
So far my nightshots have been coming out with loads of red in them but I heard that you have to turn the VR off on the kit lens to stop that.

Also was wondering what is a good upgrade? I was looking at the sigma 18-35mm F1.8 as its low F number should be good for astrophotography and it seems like its super sharp even at F1.8 unlike a lot of other lenses I've looked at. Only problem is, is that it doesn't work on full frame and was wondering if its better to go for other lenses that are cheaper and then saving for cheaper full frame like the d600 as they are so much better at high iso?